It's taking some time, about 1 year so far, but I've been making some progress attempting to create a replacement for the 70's EFI "FIV". It mounts on the air intake throttle body and allows some air bypass, which raises the idle RPM until the vehicle warms up. The core years are 76-79 but some 75 Eldorados had EFI and it was carried over in California through 1980 because the 79 system was able to meet CA emissions in 1980.
The pictures are without the internals and I am probably still at least a couple of months away from a working prototype. I was pretty happy with how the housing came out and so I thought I would let others take a look.
The blue one was created to verify my model would fit. The black one with silver (tinned brass) terminals is my housing ready for internal electronics and the wax actuator. The black one with brass colored terminals is a broken original which Bruce Roe allowed me to borrow to create my model without taking apart my car.
Scott
Link to a great related thread:
http://forums.cadillaclasalleclub.org/index.php?topic=118518.0
What material are you using to 3D print with? If it's PLA, that will work for the prototypes but it will not stand up to the heat of the engine bay. You will have to at minimum go with ABS and you may want to have them professionally printed out of something else completely from some place like Shapeways. That's who I have printing my body fillers that I'm working on.
Hi Mitchell,
The blue one is plain PLA. The black one is an engineering grade high temp PLA. I don't know if it will be or can be the final material yet. The company I bought it from is 3D fuel. They produce in the USA and they sent me the complete specification sheet. I would need to look at it again to quote exact numbers but it was roughly in the same league as bakelite. As you are alluding to there is some risk with 3D printed material because generally not many are geared to a long time functioning part. Even nylon should be in the presence of moisture to have it's best strength. I've also noticed that some older car parts made from nylon break down and become brittle. There is a material from Zortrax which if as advertised may be up to the task. I have also considered having a mold built but there is a limited market for parts like this and at some point cost becomes a factor. I will add a high temp cut-out in addition to a 2 stage heating. The original material is not marked but it seems to obviously be some form of Nylon. Any thoughts are welcome.
Scott
These things are always tougher than they first appear. Glad to have
an owner take them on. Bruce Roe
Quote from: 79 Eldorado on February 03, 2020, 10:37:39 PM
Hi Mitchell,
The blue one is plain PLA. The black one is an engineering grade high temp PLA. I don't know if it will be or can be the final material yet. The company I bought it from is 3D fuel. They produce in the USA and they sent me the complete specification sheet. I would need to look at it again to quote exact numbers but it was roughly in the same league as bakelite. As you are alluding to there is some risk with 3D printed material because generally not many are geared to a long time functioning part. Even nylon should be in the presence of moisture to have it's best strength. I've also noticed that some older car parts made from nylon break down and become brittle. There is a material from Zortrax which if as advertised may be up to the task. I have also considered having a mold built but there is a limited market for parts like this and at some point cost becomes a factor. I will add a high temp cut-out in addition to a 2 stage heating. The original material is not marked but it seems to obviously be some form of Nylon. Any thoughts are welcome.
Scott
I'm more referring to the PLA material itself and my own experiences with it in under hood environments. Most FDM 3D printers will allow for other materials like ABS and other printing types like SLS have a multitude of material available. The main advantage of an SLS print would be the lack of a distinct layer structure that could cause weak points and cracking between the layer structure over time.
From the housing material side there is certainly more investigation needed. Based on the research I did I felt that there is a solution available and possibly a few.... the best solution is still not clear. It could be FDM 3D printed and might require an industrial type printer. As you mentioned another technology 3D printer may work better. I planned to ask more questions of experts and test. I was more concerned about being able to assess the aging of materials than initial properties. That's normally where the data is not so plentiful with thinks like 3D print material. Some of the FDM materials gain a lot of layer strength with post processing and the industrial printers can do a better initial job. The 3D Fuel material is worth investigating by specification but it needs to be tested in similar situations to actual. By description it's not your average PLA. I think injection molding in something close to the OE material still needs investigating further. A third option might be a metal housing with isolation for the electronics.
I tried to approach this by breaking it down into different tasks. The housing is only one. I put this on hold early in 2019 primarily because I was looking for a wax actuator which could work for a long time. The housing design needs to be customized to what is available. The electronics and control is another item. Even the terminals weren't perfectly obvious. The originals extend from the housing farther than most I've seen and there are so many male blade terminals finding the correct one is like looking for a needle in a haystack.
Anyway more to follow.
Scott
Quote from: 79 Eldorado on February 04, 2020, 11:54:39 PM
From the housing material side there is certainly more investigation needed. Based on the research I did I felt that there is a solution available and possibly a few.... the best solution is still not clear. It could be FDM 3D printed and might require an industrial type printer. As you mentioned another technology 3D printer may work better. I planned to ask more questions of experts and test. I was more concerned about being able to assess the aging of materials than initial properties. That's normally where the data is not so plentiful with thinks like 3D print material. Some of the FDM materials gain a lot of layer strength with post processing and the industrial printers can do a better initial job. The 3D Fuel material is worth investigating by specification but it needs to be tested in similar situations to actual. By description it's not your average PLA. I think injection molding in something close to the OE material still needs investigating further. A third option might be a metal housing with isolation for the electronics.
I tried to approach this by breaking it down into different tasks. The housing is only one. I put this on hold early in 2019 primarily because I was looking for a wax actuator which could work for a long time. The housing design needs to be customized to what is available. The electronics and control is another item. Even the terminals weren't perfectly obvious. The originals extend from the housing farther than most I've seen and there are so many male blade terminals finding the correct one is like looking for a needle in a haystack.
Anyway more to follow.
Scott
Don't forget that you can 3D print it in metal also.
I modeled all of the related parts even a simple portion of the throttle body to make certain the wax actuator pin is at the correct height. The plunger Bruce sent has a metal disk inside which the wax actuator pushes (see photo). It looks a little like the "dime" he's mentioned but he wasn't certain if he had modified this one. We both thought Cadillac may have placed a metal disk in the "plunger" for the pin to push against.
My question: If anyone has a spare or their car is apart to the point the dimension is easy to check could you measure the depth from the top of the flange to the bottom of the pocket (in the case of the part I have to the top of the metal disk)? I'm looking for confirmation of the dimension indicated by the blue arrow in the attachment.
Thank you,
Scott
PS: Yes I am aware 3D parts can be printed in metal. As I know the parts from professional sources are typically very expensive. In comparison there are a lot of businesses in this area which machine parts at a reasonable cost.
I don't have a proper depth gauge but using a std micrometer I measure it to be .750 in. The contact surface for the plunger is metal.
Phil
Thanks Phil. That's what I measured as well. The only other thing which could explain why the original pin seems longer than it should be is if it's slightly extended at the temperature which I'm measuring it. I'm measuring the pin at around 65-70 degrees F so if it's shorter at a colder temp that could explain it. I didn't want to trust the pin extension only because I assumed measuring a 40 year old part I would have no idea how much it changed over time. As well I measured two and one measured 7.17mm and the second 7.91mm at the same temperature. I think I'll try placing one in the refrigerator and see if it ends up getting shorter. Even if the old part does not get shorter that seems like a good explanation. One part I was looking at does reduce the extension between 68F dropping to 59F.
Scott
After 24 hours to equalize there was no difference in actuator pin extension at 45F.
Scott
I just received a sample of the wax motor. It's shown for now in the temporary part I printed. To make certain the final has the correct length I had this one custom made so that I can adjust the length with a machine screw threaded into the end of the pin and then lock it with a nut. I'm still working on the heating portion and the control. I found some parts which should work but replies have been slow.
Scott
Very impressive work. Bruce Roe
Thanks Bruce. I need to contact the place where I was trying to get the heating and control items from. If I had the parts I identified it could go pretty quickly but they have been slow to reply even before the pandemic.
One of the other members, "AFI", mentioned the Zinc oxide paste in the original. I strongly suspected that white "wax" or "grease" which can be found even in images of NOS parts was never actually in the wax motor itself. I think what he wrote confirms that. My plan as of now is to create a custom brass sleeve which assembles over the wax motor. The heating unit and temp sensors will be mated to the brass sleeve. I need the heating unit and the temp sensor before I can finalize the sleeve though. Due to the space available and availability of parts I may need to make the housing diameter slightly larger; maybe a few millimeters. The housing I printed for test fit is the same size as the original in the photo.
Scott
I put together a temperature sensor adapter harness to allow me to measure the sensor resistance easily with multi-meter probes without disconnecting the sensor from the ECU. I'm posting it here because my plan is to use it for this project. While I'm testing I want to measure as many parameters as I can at once.
It was a bit difficult getting 2 wires in each side of the Weather pack but I could reduce the gauge to make it a little easier. I have one of the old Radio Shack Multi-meters which I love. I have 2 newer ones which have some nicer features but the Radio Shack is my favorite. One reason is the probe style. It seems it's always easier to get them to stay in place when I'm doing a job which I should have 3 or 4 hands instead of two.
I was wondering if there is a block connector designed for putting the probes in. Every search term I could think of was so generic I couldn't find anything and since I had a lot of the Weather pack connectors I decided to use one.
Scott
Quote from: 79 EldoradoI put together a temperature sensor adapter harness to allow me to measure the sensor resistance easily with multi-meter probes without disconnecting the sensor from the ECU. I'm posting it here because my plan is to use it for this project. While I'm testing I want to measure as many parameters as I can at once. Scott
I do not think you can measure the the sensor resistance when
plugged in, because there are other resistors connected inside the
ECU and voltage applied when it is on. What you might do is add
a switch to your adapter, to momentarily disconnect at least one
side of the sensor from the ECU and to your ohmmeter. An alternate
method is measure the operating voltage using your harness, which
can be used to know the resistance. Connecting a few known
resistors to the ECU and observing voltage (no need to start engine)
will give enough points to make a transfer graph. Or I could try on
mine, not quite identical. Bruce Roe
Quote from: bcroe on April 05, 2020, 11:50:05 AM
I do not think you can measure the the sensor resistance when plugged in, because there are other resistors connected inside the
ECU and voltage applied when it is on. What you might do is add a switch to your adapter, to momentarily disconnect at least one
side of the sensor from the ECU and to your ohmmeter. An alternate method is measure the operating voltage using your harness, which
can be used to know the resistance. Connecting a few known resistors to the ECU and observing voltage (no need to start engine)
will give enough points to make a transfer graph. Or I could try on mine, not quite identical. Bruce Roe
Very good point Bruce. When I have a chance to get to my Eldorado I could see what it reads with the adapter connected and vehicle off. Maybe it doesn't add much information anyway. Before I thought of this I was thinking I would simply probe places with my IR pyrometer. I really just wanted to record temperatures so even with the extra harness I would need to back out the temperature.
Thank you as always for your valuable insight.
Scott
Quote from: 79 EldoradoThank you as always for your valuable insight.
Scott
Teamwork gets the job done. Bruce
I discovered something today...a part which seems is not needed and may even cause a failure mode. The other night I was reading one of the Cadillac Fuel Injection Diagnostic Manuals and I read the following: "A “latched†FIV is a condition where the retainer clip becomes “latched†below the seat, thus holding the valve in its closed off position, Fig. 2. To check for this condition, remove the valve and visually inspect."
I immediately thought that sounds like the retainer clip slipped down below the "Derby" (the sleeve where the plunger goes through see capture below). The interesting thing is I've been wondering how the assembly could let enough flow past it to work if the retaining clip is below the derby. That was the position it seemed it should be in because if not there seems to be no reason for the retaining clip. Once the clip goes past the edge of the derby there is only a fraction of a millimeter gap and when the actuator extends the plunger goes deeper closing the gap. The coil spring which pushes the plunger back up is pretty strong so the fractions of a millimeter could be slightly more if the clip deforms (it does deform/deflect some).
A couple of days ago while working with the plunger assembly I accidentally broke one of the legs off the retaining clip. I was in a panic because I'm sure it's a hard to find part and second because I wasn't putting a crazy amount of force on it when the leg broke.
Fast forward to today. I planned to measure assemblies in the spare TB Bruce loaned me. I realized I could measure the plunger depth from the bottom of the TB and I could compare the used parts to the actuator samples I had made. I decided to work on it today despite breaking the retaining clip because I questioned whether or not there was any functional reason for the retaining clip. Not only did I question the need I started to think it could break and fall into the intake manifold.
The only other function I can think of is as an assembly aid; keeping the spring on the plunger during assembly. I'm not sure that helps significantly. To assemble I placed the derby in the TB recess; I placed the spring on the derby; I placed the plunger on the spring and then I used the FIV heater to push straight down on the plunger flange. Once I pushed it to the proper depth I turned in CW 90 degrees and allowed it to come back up in the locked position (a locking tab is on the foot of the heater and there is a pocket in the TB which the tab sits in preventing rotation of the FIV heater) .
Based on the correct extended position the clip seems like a risky item. There just isn't a lot of room for error. I don't think I will run out and remove my clip but if I need to take the spring off I think I will remove the clip. My plan for the replacement is to remove the external switch and fragile arm. That's the only thing I can think of which might be at risk with the clip removed but even with the clip present you still need to compress the spring and turn the heating unit 90 degrees against the spring force (so it's still not really protecting the arm).
Unless something changes my mind I will recommend removing the clip if I am successful in creating a replacement. Keeping the clip is too much of an opportunity for a customer complaint for what seems to be a known, and avoidable, failure mode.
Any thoughts?
Scott
Just a couple random thoughts here. I wonder what current/power
at 12V your device will consume? This is not very critical as the
circuit is large enough to run 2 pumps. What matters is roughly
the right timing. I note a couple different parts numbers for the
small and big block engines, though it probably matters little.
Going backwards the Cosworth used a simple air valve that got
12V to add air, then abruptly closed at 125F coolant. Just a step,
maybe no worse that dropping off a carb linkage step. Cad has
an IDLE STOP SOLENOID in the throttle body, wired to add some
throttle air when the AC compressor is engaged. Probably not
enough, wonder if it could be used like the Cosworth? Bruce Roe
Quote from: bcroe on April 09, 2020, 02:20:53 AM
Just a couple random thoughts here. I wonder what current/power at 12V your device will consume? This is not very critical as the
circuit is large enough to run 2 pumps.
Bruce,
I'm trying to stay very close to the original draw. I calculated just under 1 Amp. My assembly will have some internal parts acting as the heat sink which will be a little different in mass so I may need to vary some but I intend to stay close to the original.
Quote from: bcroe on April 09, 2020, 02:20:53 AM
What matters is roughly the right timing. I note a couple different parts numbers for the small and big block engines, though it probably matters little.
I had one of the original actuator you sent measured professionally. I then found an actuator wax which matches the progression extremely closely. I am pretty happy with that part.
Quote from: bcroe on April 09, 2020, 02:20:53 AM
Going backwards the Cosworth used a simple air valve that got 12V to add air, then abruptly closed at 125F coolant. Just a step,
maybe no worse that dropping off a carb linkage step. Cad has an IDLE STOP SOLENOID in the throttle body, wired to add some
throttle air when the AC compressor is engaged. Probably not enough, wonder if it could be used like the Cosworth? Bruce Roe
I remember you described the Cosworth air valve operation. That seems like it would be pretty abrupt. I think that "Idle Stop Solenoid" would be pretty easy to set-up. It could be relay and a temperature switch used to switch the relay. I don't know if it would be enough but it's an interesting idea. I'm getting close to a drop in. I still need the heating elements and control. I have a couple of options I'm trying to follow. Sometimes getting samples has been an issue. I do think I found appropriate control means for each of them. Once I have some samples of the heating elements I still need to design the interface between the wax actuator and the element. My thought is a custom brass sleeve with possibly an extended surface like a heat sink because the space around the wax actuator is small and some of the items which need to be in direct contact may be too difficult to fit without making use of the adjacent cavity.
Any thoughts on that clip? I don't see any reason for it. Even if it was for high volume assembly for anyone working on their own vehicle (not on an assembly line) it seems like it has no value... only headache if it gets "latched" or breaks and falls in the intake.
Scott
These work just like many of the electric chokes? You get system voltage anytime the engine is theoretically on and it stays at full voltage till you shut the engine off? You mention the fuel pump circuit? Does this work like more modern systems where it won't stay on if the engine isn't turning?
Quote from: TJ Hopland
These work just like many of the electric chokes? You get system voltage anytime the engine is theoretically on and it stays at full voltage till you shut the engine off? You mention the fuel pump circuit? Does this work like more modern systems where it won't stay on if the engine isn't turning?
The 70s Cad cold idle air valve is on the same circuit with the
fuel pumps. And shuts off when they do, including shortly
after the engine stops turning. Off, it will take time to go all
the way back. But valve power comes out of the ECU on a
different pin, taking advantage of that has allowed saving so
many ECUs with burned out pump power pins.
As for the clip, this electrical type has no idea of how to deal
with unlubricated sliding surfaces. Bruce Roe
Quote from: bcroe on April 09, 2020, 02:20:53 AM
...I note a couple different parts numbers for the
small and big block engines, though it probably matters little.... Bruce Roe
Bruce,
I was able to search the GM parts wiki page for the Bendix PN on the FIV I had from you. It goes to a scan of the GM paper catalog. The Bendix number, 1181290, is listed as reference under GM PN 1606776 and it lists '76-79 "All w/E.F.I." (All meaning all motors and models). The next line does list a different PN for 1980. That PN is 1617956 and it also says "All w/E.F.I." (Meaning all 1980 as opposed to the line for 76-'79).
While I was researching this searched for any available photos I could find online. I did notice that the lever actuated micro switch on the side did have a different identification number on some versus others. I saw some with "E63" and some with "E62". When I dug further I found one number was capable of handling higher amperage than the other. The strange thing seemed to be the magnitude of the difference unless the source I found was wrong. I took pretty good notes and the E63 was listed as 0.1A and the E62 was a 10.1A version. Maybe there's something in that detail other than the maximum amperage because these FIV seem to need 0.92 Amps (at maximum nominal resistance). Anyway if GM had Bendix change the micro switch it would have almost certainly driven a different FIV assembly PN in my experience. That could be the reason for seeing other PNs. I doubt that's the difference for 1980 though because GM likely would have simply obsoleted a PN if that switch changed (not list two in the catalog).
I've also seen some photos of "white" (normally discolored to yellowish) plungers and others with black plungers. Maybe the color difference was associated with certain motors?
Quote from: bcroe on April 09, 2020, 04:38:21 PM
….As for the clip, this electrical type has no idea of how to deal with unlubricated sliding surfaces. Bruce Roe
I didn't catch why the clip would help that. Are you thinking maybe it helped center the "plunger" in the "derby"? I know when I assembled the parts once on the TB it was really easy to slip and "latch" that clip. The wax motor has good pushing power and the spring it relatively heavy for returning the plunger once everything cools down. I just have a hard time believing the clip could have helped.
Scott
Quote from: 79 Eldorado
Bruce,
I was able to search the GM parts wiki page for the Bendix PN on the FIV I had from you. It goes to a scan of the GM paper catalog. The Bendix number, 1181290, is listed as reference under GM PN 1606776 and it lists '76-79 "All w/E.F.I." (All meaning all motors and models). The next line does list a different PN for 1980. That PN is 1617956 and it also says "All w/E.F.I." (Meaning all 1980 as opposed to the line for 76-'79).
While I was researching this searched for any available photos I could find online. I did notice that the lever actuated micro switch on the side did have a different identification number on some versus others. I saw some with "E63" and some with "E62". When I dug further I found one number was capable of handling higher amperage than the other. The strange thing seemed to be the magnitude of the difference unless the source I found was wrong. I took pretty good notes and the E63 was listed as 0.1A and the E62 was a 10.1A version. Maybe there's something in that detail other than the maximum amperage because these FIV seem to need 0.92 Amps (at maximum nominal resistance). Anyway if GM had Bendix change the micro switch it would have almost certainly driven a different FIV assembly PN in my experience. That could be the reason for seeing other PNs. I doubt that's the difference for 1980 though because GM likely would have simply obsoleted a PN if that switch changed (not list two in the catalog).
I didn't catch why the clip would help that. Are you thinking maybe it helped center the "plunger" in the "derby"? I know when I assembled the parts once on the TB it was really easy to slip and "latch" that clip. The wax motor has good pushing power and the spring it relatively heavy for returning the plunger once everything cools down. I just have a hard time believing the clip could have helped. Scott
Maybe the clip keeps it from squeaking?
A 0.1 A switch is not adequate for the current, sounds like a
computer signal type. Maybe they figured it out and changed
it in production. I believe (in my collection of units with a
broken switch) I observed a couple somewhat different heater
resistances, presumed for different timing.
The Cad valve may be much smoother closing, but the Cosworth
keeps working.
Bruce Roe
Bruce,
Regarding the clip I think they just wanted the spring to be more compact/shorter during assembly.
I couldn't believe when I saw 0.1A on the micro switch. I wonder if what I saw was a misprint and maybe it was 1.0 Amp. They look so similar I couldn't believe one would be capable of 100x the current... doesn't seem to make sense but it doesn't matter now.
That Vega FIV solution may have lasted longer than most of their cars. Although to be fair the first and only new car my parents ever bought was a yellow Vega wagon. That particular car lasted over 200K miles. It was using some oil by then but it wasn't a disaster either.
Scott
Quote from: 79 EldoradoBruce,
I couldn't believe when I saw 0.1A on the micro switch. I wonder if what I saw was a misprint and maybe it was 1.0 Amp. They look so similar I couldn't believe one would be capable of 100x the current... doesn't seem to make sense but it doesn't matter now. Scott
The switch difference is probably just in the contact. Back then we
used a lot of switches (imagine rows of 24 for a 24 bit machine) in
computers, but the current was so tiny, it could not clean the contact.
They would oxidize over at 3V. So the contacts were gold plated, but
with very limited current capacity. Same for these in some aps.
Bruce Roe
Just a quick update: I was able to order components for a couple of different heating element and control schemes. Lead time is about 3 weeks.
The next piece I need to work on is a thermal mass/ sleeve to go around the actuator body. As well as providing some thermal mass it's also needed to provide enough surface for the heating and sensing parts. I didn't want to spend much time on that until I had some of the other items in hand but I may start on at least a version for one of the options.
Scott
I ran a baseline test on my car today. To me it seems normal. The RPM seemed to settle down in the time roughly reported in past threads but that said the current never got as high as I thought it would by voltage and resistance. It makes me wonder if one resistor after the mechanical switch is bad?
RPM provided by my timing light's tachometer, temp was taken at the water neck using a thermocouple (tried to make certain it was in contact but not 100% certain), DC Amps (reported as mA to be more visible on the same axis as temp) using a Hall effect sensing loop zeroed in place before starting. I was working alone so I had everything set-up but the timer started about 5 seconds after the actual start.
The temp in the photo to look at is the one labelled "KTC"
Not a big fan of this version of Office... I like the old graphing tool better but anyway it gets the point across.
Scott
Quote from: 79 Eldorado
I ran a baseline test on my car today. To me it seems normal. The RPM seemed to settle down in the time roughly reported in past threads but that said the current never got as high as I thought it would by voltage and resistance. It makes me wonder if one resistor after the mechanical switch is bad?
RPM provided by my timing light's tachometer, temp was taken at the water neck using a thermocouple (tried to make certain it was in contact but not 100% certain), DC Amps (reported as mA to be more visible on the same axis as temp) using a Hall effect sensing loop zeroed in place before starting. I was working alone so I had everything set-up but the timer started about 5 seconds after the actual start.
The temp in the photo to look at is the one labelled "KTC"
Scott.
Scott, is this a run of OEM parts, or the new components you ordered
in April? It looks like what is supposed to happen. The resistor current
I do not understand, I expect a higher start current and then a step
down as minimum idle rpm is approached.
Measuring current, my experience is that Hall clamp on devices have
poor accuracy at these low currents, and tend to start drifting (zero
set) before long. My preferred way is to insert a low value resistor and
measure the voltage drop across it (shunt). Perhaps I could send you
an adapter harness to insert in the heater feed, with a 0.1 ohm resistor
in the path you will see 100 mv across it per amp of current flow?
nice work, Bruce Roe
not very accurate at these
Hi Bruce,
That run was with the OEM parts. My car has always acted "normal" but my car is the only reference I have to this FIV type system.
I was also expecting to see exactly what you described. The meter I used does have a low set point, 2A, but point taken on the drift. The instructions say they need to be zeroed each time before measurement and I read that they are sensitive to magnetic fields. I did notice when I turned everything off there was a stray reading. I'm almost certain it read 0.126 Amps; so anyway not zero as was the case before starting. Given the car acted as it did it would be hard to believe it would have acted as nicely with only half of the heating.
I don't have any OEM type connectors to assemble an adapter harness but I like your idea and I could set it up if I had an adapter like you described. If you are willing to put one together I would certainly try it.
One of my friends said he might stop down this week in case I get in a situation where I wish I had an extra hand. I was fortunate the multi-meter was stable sitting but I would have liked to have someone watching as the car was started with the wires and monitoring devices instrumented.
I have everything needed to assemble the prototype now except the brass sleeve. Those are close. The temperature controller is a little different than what I was expecting but I think it will work.
As always thank you for your suggestions an your thoughts,
Scott
Scott,
A current shunt to aid your project may get there Thurs. You
can plug it into your wiring, read out the current accurately
with a DVM on 2 access wires. thanks, Bruce
Bruce,
Received and working perfectly! I only added a couple of connectors to the green and white wires so my DVM leads could plug in and stay put to avoid another reason to wish for extra hands :)
The place I got the thermal actuator from added 5mm to the lengths I told them I wanted to try. I guess better too long than too short but the pin they use is very hard steel. I broke a tap trying to thread it while making an adjustable version for trial. After breaking the tap I decided to get the closest brass rod I could find. I created the replacement pin by turning the rod down/cutting to length. I just tested the set-up you sent me with the first prototype on the kitchen floor. The replacement is drawing 0.9 Amps when it's on. The controller samples something like every 20 seconds and allows heating if the temp drops below the "on" set temp.
I likely need to do one more redesign of the housing because everything is very tight. The assembly was very difficult. I finally decided I would leave the top off for the trial. I think I will increase the height slightly but I will keep the terminals at the same height.
I also came across the comment in the 11x17" Electrical trouble shooting manual that the FIV should take between about 1.5 and 5 minutes depending on the conditions. My earlier trial with original 40 year old parts now seems as if it took too long even though my perception was the system was working properly.
Scott
Edit: Added photo with Bruce's harness hook-up for measuring current draw.
That is great work, hope I can continue to provide some assistance. Are
you planning to continue using the switch? It occurs to me there might
be an electronic way to reduce current after warm up. Remember the
color TV pic tubes, used a degaussing coil at turn on. It was fed through
some thermistors that heated up and changed resistance to turn it off,
no moving parts. Bruce Roe
Bruce,
There are some PTC heaters and I was thinking about using one with a fixed resistor to get the desired output. When it hits the proper temp the resistance would be so high it would essentially have no heating. I even bought some parts to try but the problem is space including mounting the heating device in thermal communication with the actuator. If I could dictate exactly the PTC heater size/ resistance maybe but there is a lot to pack in a small shape.
This set-up uses a smart controller and a temp sensor. I was able to select the programmed off temp and restart temp. That gives me minimal connections but the space is still tight.
I also had an idea for a dual stage but it required more connections and 2 separate heating elements. I also needed to extend my heat sink to mount everything. After I put this first one together I doubt I have room for the dual stage.
With this first controller design there will be no switching arm like the original. The number of on-off cycles is reduced by the staggered off-on temps. The controller is rated for millions of cycles. Now that I know everything works inside I can determine the time between switches. To make that time greater, decrease the number of switches, I made certain the heat sink was about as large as it could be. That also has an impact on the heat-up time. The first time I powered it on I didn't start from equalized to measure but after it achieved the target temp it seemed like the time before the next cycle was sufficiently long. I will probably take the measurements tomorrow. Now that I know the parts seem to be pretty stable I may try it directly on my car but the bench test is good to see if things seem to be working as normal.
I know I probably need to spend at least a day reworking the size to fit things a little more comfortably. It probably needs to grow only slightly but I may change how I secure the terminals when I do it.
You always provide great helpful ideas :)
Scott
Bruce,
I tested the FIV you had indicated as "OK". As you already knew the resistors checked out fine and the switch is working. I think the issue with these is the thermal paste is likely providing the thermal communication between the wax actuator and the heating element and when enough of that leaks out the thermal link is somewhat broken so it takes a really long time to heat the wax actuator.
So in this example I got good movement from the wax actuator (probably nothing wrong with the actuator). The total travel was about 4.3mm. The current shift due to the switch position finally occurred at 10min 19 seconds. I almost gave-up on it but it finally happened and it was obvious. So I think everything with that FIV works with the exception of likely there is little thermal paste still present. I was only bench testing it but I had it set-up in the spare throttle body with a depth gauge on the center of the "cross" (bottom of the plunger).
One other thing I noticed was the current was a little on the low side after starting at what I thought was slightly high. It started out at 1.19 Amps but within 4 seconds it was down to 0.94 A at 24 seconds 0.82 A at 46 seconds 0.79 A. There was some small drop after that every couple of minutes down to 0.66 A at 6 minutes where is stayed constant until just before switching. After the switch it went from 0.66A to 0.37 Amps. I haven't graphed the data yet.
I also tested my prototype with this set-up. I did it with the brass pin I made as well as the steel pin which came with the actuator. I think something slipped during the test with my pin. My pin is rough and I should try it again. I switched to the steel supplied pin to measure the travel and that was very close to the "OK" part. The target temp was reached in 1min 39 seconds. It was at least 80F here with a high predicted to be a record breaking 88F. Considering the Troubleshooting manual listed between 1.5 and 5 minutes I thought 1min 39 wasn't too bad considering the ambient and no airflow around it.
Scott
I ran the test with my brass pin one more time. It repeated the steel pin test. My dial indicator must have slipped during the first test. See graphs attached. The next test will likely be on the car with RPM. Since every original I have has a different pin length this first brass pin is a bit of a guess and I think I kept it just slightly longer than I expect it should be.
Scott
Have you somehow replaced the missing paste? Bruce Roe
Quote from: bcroe on May 28, 2020, 09:01:31 PM
Have you somehow replaced the missing paste? Bruce Roe
I haven't tried to replace it. I thought about it but the thermal paste I have is electrically conductive so I didn't want to risk trying it. Based on your question I bought some non electrically conductive paste which should work. When it arrives we can see what happens.
One problem with the original design is it seems the only thing stopping the paste from seeping out is a tight fit but it's obviously not that tight. Even NOS parts I've seen photos of show signs the white paste is coming out. One person even stated it was normal; while true still not ideal. My design very likely doesn't require any paste. I decided to use some to keep the thermal connection consistent but I added an o-ring on the gravity side. I even made certain the o-ring was compatible with alcohol containing fuel. My thought was worst case there should only be residual fumes from evaporation but I didn't want to take any chances.
Scott
It is evident to me, in an effort to quickly get out a then best state
of the art performance, they slapped together a lot of somewhat
revolutionary new stuff and did not do enough testing. With the new
digital designs in sight, no more effort went into fixing these. Now in
hind sight we are slowly working out all the bugs.
My ECU work has gotten more complex than a very simple repair,
because I also try to head off other potential future failures.
Bruce Roe
Quote from: bcroe on May 29, 2020, 10:30:14 AM
It is evident to me, in an effort to quickly get out a then best state of the art performance, they slapped together a lot of somewhat
revolutionary new stuff and did not do enough testing. With the new digital designs in sight, no more effort went into fixing these. Now in
hind sight we are slowly working out all the bugs.
My ECU work has gotten more complex than a very simple repair, because I also try to head off other potential future failures.
Bruce Roe
I think you're spot on with the comments... Thankfully the system was used for several years. I cannot image what would have happened if it was 1 year only.
While researching the o-ring for this I contacted a direct manufacturer expert and they recommended Flourosilicone since the most common fuel now has 10% alcohol. I think that material would be good for the fuel injectors seals as well. They are expensive even in quantity but not break the bank expensive. I still plan to do mine and I was thinking of copying the size in one of the kits and buying the Flourosilicone version of the same thing. I will need to remind myself which kit you thought had the correct sizes to reference.
I just went out and tested the prototype on my car with the brass pin I made. I thought I made it conservatively a little long but the pin on my FIV was longer than the ones you sent for reference (I'm sure the physical pin is the same; simply a result of temp and condition of the wax actuator I guess). I also checked the depth of my plunger seat because my car has the "natural" color version and I was measuring the black one you sent. They seem to measure the same (rim to where the pin pushes).
So my preliminary conclusion is it basically acts the same on the car as on the bench. The starting RPM was higher because my pin was shorter. I can also see I need to raise my idle RPM slightly. It was always a bit low but because it wasn't stalling I wasn't touching it. I couldn't believe it didn't stall this morning. It got down to between 460 and 470 RPM but one blip reading was even 435. I need to pull out the books and see what the idle RPM should be. When I started it (giving me ~3sec to run from the key turning to the passenger side and hitting record) was 1510 RPM and it increased very slightly for the first few seconds to 1560-70 before going back down as the pin extended.
Here's the graphical form of the data with the bench current as reference. Bench test shows pin length but I thought it would still be a reference so I added RPM to the secondary axis.
Scott
Looks like a good run. Your idle might have been set low before, to compensate
for a FIV that did not fully close.
Why does the current keep changing after the pin stops moving? Bruce Roe
Quote from: bcroe on May 29, 2020, 03:12:16 PM
Looks like a good run. Your idle might have been set low before, to compensate
for a FIV that did not fully close.
I suspect you are correct. I need to make some progress on a couple of non car related projects before I go back to it :(
I found the instructions in the "Big red book" 6C-98. It talks about a lock nut but at least on the TB you let me borrow it looks like a supersized version of a Q-Jet idle screw with only a spring and no locking mechanism (does not inspire confidence as easy as it turns). I guess it follows the same logic as the Q-Jet meaning tighter = slower. The book says 600 RPM in drive with vacuum plugged. I will need to get a helper to operate the brakes. I was expecting to see 650 but the Eldorado and Seville are lower; "C" car shows 650. Mine is very low if I'm getting mid 400's in Park.
Quote from: bcroe on May 29, 2020, 03:12:16 PM
Why does the current keep changing after the pin stops moving? Bruce Roe
It needs to maintain the set temperature. So once it achieves the "off" set point the controller just samples every so many seconds to check to see if the temp has dropped below the "restart" temp. When it samples it draws 0.04 Amps (Volt meter showing 0.01 Volts so maybe even lower as I do not have another decimal place). Once the temp drops below the restart you see the full 0.9Amps again but for a shorter time because it's starting from the restart temp and not ambient.
Oh I also checked the resistance of my original and switch open and closed yields almost the same value (26-28Ohms) so one of resistors is bad. That one eventually gets close to closing, even with one resistor bad, because the minimum RPM was getting down to around 540 RPM.
Scott
I sent my 3D models and drawings out for quote for the housing and cap as injection molded parts. That's the last real part I need. The quote did come back. I'm working through the details. It's not cheap but it seems like the best solution.
I should have an update in less time than it took to post this one. Home projects....
Scott
I ended up getting some professional 3D printed parts which Mitchell (MaR) was suggesting early in the thread. They were made using an SLS process out of glass filled nylon. The best material was only available in off white instead of black but the parts really look good and we made certain to print them in an orientation which would give the maximum strength in the critical direction. It's still not cheap but at least, unlike the injection mold, the brunt of the cost doesn't need to be spent before the first part is made.
I have one working in my own car now. I'm still tweaking the values based on tolerances and I'm working out the details to allow an abnormal operation shut-off.
The one in my car has the shortest extended length pin (actuator tolerance) and the slowest heating (heating element tolerance). I tried the tallest extended length and the fastest heating last night. It worked as well; RPM came down faster but to the same value. Because my plunger (the thing the FIV pushes against) was pushed farther than it had probably traveled in at least 30 of it's 40 year life the plunger got stuck on the residual carbon build-up. I cleaned it and after cleaning it worked as normal.
Also interesting is there is no wire clip on my car and no witness marks seeming to indicate it's been gone a long time. After studying these as much as I have I would recommend removing the clip and being cautious with FIV replacement if you still have a switch arm. The clip only seems to have the function of keeping the return spring partially compressed during install and removal. If you have a clip you risk the FIV becoming "latched" which is clearly stated as a failure mode in the Cadillac Electronic Fuel Injection "Blue book" and second they can break and you then run the risk of having a clip go through your motor.
Scott
An actual working replacement is pretty impressive, I wonder if the General
worked much harder to do them? Bruce Roe
Quote from: bcroe on August 13, 2020, 08:36:06 PM
An actual working replacement is pretty impressive, I wonder if the General
worked much harder to do them? Bruce Roe
Bruce,
I'm really pretty impressed at what they were able to do over 40 years ago. They had more available resources at their disposal though. I also think a lot of the credit needs to go to Bendix. They should have concentrated a little more on long term durability but the overall system design wasn't so bad when everything was working.
I ran 3 more tests tonight to cover the tolerance range of the actuators. I'm missing one test to fill the max RPM at start-up matrix. I finished the minimum stabilized RPM matrix tonight. I'm still zeroing in on the nominal pin but even with the range I used I would say every combination was probably acceptable; meaning I could have fine tuned with the idle screw on the front of the TB. I think when these are changed that adjustment will be necessary anyway. I also measured the total turns possible on the TB idle screw. From completely removed to fully seated it was 21.5 turns. I didn't check the total usable range but it's likely around 8 (fully closed to passage fully open).
The controller I'm using has some built in precautions for abnormal behavior. The three I have now are missing one of those available control schemes which I want to add. I will also adjust the resistance of the heating element some based on the necessary manufacturing tolerance and equalization time. Once I have the updated controllers and heating element I do plan to send you one to try.
Scott
My car has put-up with a LOT of testing. I’ve finally decided on what I feel are the final adjustments. I’m ordering 3 more of the key electronics, in what I believe is the final configuration, for a final verification before committing to a larger quantity to get the price down. The sample quantity prices are painful.
Other than testing I created a calculator which is able to estimate the heat-up time for a given resistance. I also used the CAD model, of the FIV assembly and the TB key parameters, to make a spreadsheet based math model for determining the best target for the actuator motion. The math model makes the position where the plunger overlap, relative to the actuator motion, more obvious. I can vary parameters and immediately see the bypass gap or overlap value. To explain the car RPM should plateau before the controller off command. That means there is overlap beyond the plunger initial close position, linear position when bypass equals zero, and the final plunger position. That’s important because it allows tolerance and it adds stability during control. I learned during this project that the tolerance of the actuator stroke is based on an internationally accepted tolerance; 10% of the total stroke.
My original, with one bad resistor, seemed tolerable at the time but it’s so much better now.
Scott
One of the forum members was having an issue with his '76 Eldorado convertible. Very nice dark brown color with white interior. He inspired me to write-up a removal / installation instruction sheet. It's a draft which I intend to add photos to but once it's done I will post it on the forum.
His car now has "proto3" with a custom length pin installed and working. He even took some photos while going through the procedure ( a couple are attached). The plan is to swap proto3 with one of the final versions once they are done. He was thinking about parking it for the season. I've been in the same situation where something cuts the season short and it's not a good feeling.
Scott
Very impressive, keep us informed on the trial. Some of us do not stop
driving 70s cars in winter. Bruce Roe
Bruce,
The member found me through you. Following the repair he is getting a lot more seat-time and he now feels safe driving his car. I think he will post an update directly.
As I posted the update the fact that you continue to drive your car, as some of us store them, was certainly running through my mind. I wanted to send you one of the three prototypes. My primary reluctance in sending one of my prototypes to you was my rather crude actuator pin. It works but I don't have a lathe so to test different lengths I used my drill press to turn down the closest diameter I could find to the required 4.6mm. I have a crude pin in my car but if I drop it while working over the TB I have only myself to blame.
For "proto3" I sent out I cut down the only original pin which was long enough to be the ideal length. I have 3 samples but the other two were ordered with intentionally short pins thinking I could thread them and use an adjustable machine screw with a lock nut. The pin material is 304 stainless and I anticipated needing "flats", to grasp it while threading, so the diameter I could tap was really small. I thought I could do it but the tap was small and the material was so hard I broke my tap after the third or fourth thread. Anyway I placed a larger "production" order for the wax actuators and I am within a couple of business days away from placing the order for the key internal electronic parts.
There are a couple of other parts I need but those parts are either the same or very similar to the prototypes. So other than the actuators and electronics I currently have enough parts to make 7 more assemblies. I think the timing to replenish the items I have 7 sets of will be similar to the actuators and electronics.
I'm anticipating having these available sometime in October. I don't think the timeline will slip.
Scott
Hi all.
I am the member who was fortunate enough to try out Scott's newly minted FIV piece. A little back story on my 76 Eldo...
It's a low mileage car at 62k miles. It gets driven only between late May and mid October, after which it is put away for the winter. I'm located in New England, so for reasons of salt and the fact that I winter in Florida, the car is parked in my well-ventilated, elevated barn and the battery is then moved to a tender in my basement. All told, I normally drive the convertible about 1,200 miles per summer season.
This year, upon first starting the car in late May, I noticed it would not idle down while in DRIVE. The motor seemed to be constantly revved at very high RPMs, and required heavy braking to keep her under control in the hills where I live. It simply was not safe to drive her and distance. Because of this, I drove it very little, and then only two or three miles to keep her exercised a bit.
Reaching out to Bruce Roe, he offered great advice and also mentioned Scott and his quest for a better FIV. The rest, really, is history. I am by no means a mechanic, but I can generally find my way under the hood of a car. Having very few auto repair shops here where I live, and knowing the rarity of the fuel injection system on these cars, I began my quest to fix the car mostly out of necessity. Otherwise, I'd not be able to enjoy Vivienne on those great summer days.
This FIV manufactured by Scott is the real deal. I was able to replace mine in well under 30 minutes. The only issue after replacing the part is then fiddling with the idle screw, which takes all of 60 seconds each time. This was a hit or miss situation, as I adjusted it over three days until I felt the car was right where she ran at her best. All told, the replacement of the FIV and idle screw finessing was very easy. I was apprehensive (to say the least), but Scott's directions and his new FIV make it an easy proposition. I feel very comfortable (and happy) driving the car. Monday I took her out in nice weather. I drove her 23 miles as I ran several errands. Stopping three times along the way, where she sat for five to ten minutes each time, she started right up and drove as one would hope! No more high idle and reining her in as I drove.
If the FIV is the problem, then Scott's piece is the answer. Feeling comfortable as I drive with the top down, Simon & Garfunkel in the 8-track, that's what it's all about for me.
I'm happy to answer any questions should anyone have any. Thanks so much, Scott!
Joel
Thanks for posting Joel.
The actuators arrived a week ago Monday (see photo attached). I replaced the actuator in one of my prototypes with one of the new ones. That sample was tested on my bench test, using the extra TB Bruce supplied, and it iworked as intended.
The last electronics part is later than I expected. All of the items I initially saw as difficult have been sorted but I've been working with the supplier to get the best wire available for the assembly. My first selection from their current supplier was not something stocked and thus there was a very large minimum order quantity. I did find an alternative supplier for the wire so hopefully things will start moving again more quickly.
Scott
The final part I was waiting for should arrive tomorrow the 9th of December so I should have another update soon. I want to try everything out with the parts I have before I order more of the custom brass sleeves I've been using.
Scott
The assembly with all of the final parts is finally done and ready to confirm! I'm including a photo of that first part. It's pictured still in a quick-clamp while the adhesive cures. The thing at the bottom of the FIV is an interface I 3D printed to allow the 2 halves of the FIV to be clamped with even pressure over the surface; needed to avoid the pin/actuator and distribute the load over both "feet".
The local company making the brass heat sink had some time on a machine so instead of modifying one of my prototypes I decided to wait until they had the final version. That was this morning. I approved the design today so I should have more heat sinks coming soon. I only have 7 housings left but I spoke to the supplier today to get more.
I'm pretty excited with the way the first one came out. I will wait the full 24 hours, full cure time for the adhesive, before testing it. Even though the cap sees no load I want to let it fully cure.
Scott
Lots of work there, guess it will be a while before trials are complete.
Bruce Roe
Bruce,
I've done so many tests, taken so many measurements, have so much data and have the TB area around the FIV modeled with an interactive workbook which tells me the gap/overlap. I should really just need to test it on my bench test and check the numbers against my existing data. I'll either do it tomorrow or Wednesday.
I patterned the resistance using one of the prototypes. I've already tested/verified the wax actuator and pin length. Those items are key. I did change the sleeve slightly for some added internal clearance but it was and still is a pretty significant heat sink. The final, hopefully final, design is modeled after the part I have in my car. The part in Joel's car is faster acting than what the final values targeted. The part Joel has still worked pretty well once I adjusted the pin length. There seems to be a fair amount of room for variation to have an acceptable part. The standard tolerance for the heating element was +/-10% which I think would have been ok but I was a little concerned and the supplier agreed to keep the parts I purchased within +/-6%. Joel's part was around 20% lower resistance than mine.
Scott
The first part is bench tested and it worked as expected. I'm attaching a portion of the test data summary. The first line is my "Proto1" and the second for this first sample.
If you take the gap at the beginning of the test and subtract the "gap" (negative because it's now overlap) at the end of the test you can get the total pin travel.
Scott
I took some photos after removal from the clamp and after testing.... See attached.
Scott
Quote from: 79 EldoradoI took some photos after removal from the clamp
and after testing.... See attached. Scott
That certainly does look professional and expensive. I suppose you are now into
calibrating things like the time delay, rod movement, and power usage? There is
plenty of 12V power available from the fuel pump circuit, I suppose the original
used that delicate switch to keep it from getting too hot. Bruce Roe
Hi Bruce,
All of the things you mentioned were part of the two years worth of testing. So I do have some excuse for taking so long :)
While I was testing I tested 2 heating units which were around 13 Ohm and one which was around 16 Ohm. What we need depends a lot on the mass and how well the heat is transferred to the assembly. As you suspected the pin length also complicated things.
There were a couple of major break through instances which helped. The first was when I decided to CAD model the entire section of the TB and the second was realizing that these wax actuators are only consistent equalized at a pretty decent load and after sitting under load for around 30 minutes. In fact months were spent because I was concentrating too much on the "cold" load as the spec point and made worse because I didn't realize how critical the load was as the design point. What was worse was I had been communicating to the a partial load just based on the spring constant and not really in the assembled/ compressed cold position. To get within their actuator design range it was even better to use the load at full compression. By that I mean the spring compression once the pin is fully extended and the plunger compresses the spring as much as it can.
The 3D model and resulting workbook I developed allowed me to perfectly spec the pin length I needed. The wax actuators follow a curve so once you know a single point the curve gives you the rest.
I then did a lot of testing at ambient, in the car and on the bench, and with part which had been in my freezer over night on the bench test. Using the time versus temperature, known resistance, and known voltage I was able to create another workbook to estimate time at other conditions and using different resistance values. The resistance heaters have a standard tolerance of +/-10% so I used the workbook to develop an acceptable range. As I mentioned the supplier also agreed to reduce the standard tolerance to +/-6%.
In the chart I posted the "gap" measurement my workbook calculates that from information entered regarding plunger distance from the bottom of the TB. The actual gap is impossible to see but since I modeled all of the parts I can simply use math to "see" the value.
So the draw during heat-up for the first sample was around 0.92 Amps. The range should always be between 0.86Amps and 0.97 Amps. Once under control the electronics simply sample and prevent anything significant from passing through to the heating element.
None of the major components was off-the-shelf so it worked out that I was able to find supplier who were willing to create custom parts just for this application. I'm really pretty happy with the way they came out. I picked-up more brass heat sinks this morning so I will soon assemble 6 more parts (limited by the number of housings I have until the end of the 1st of January).
Scott
I'm posting the instructions I originally wrote when I sent Joel one of my prototypes (see attached pdf). I've updated it and added some pictures... It's a lengthy read but I wanted to be thorough. I was thinking about even adding a second page of pictures. Anyway if anyone is interested please take a look and suggestions are welcome...
Scott
Now listed on our forum here:
http://forums.cadillaclasalleclub.org/index.php?topic=162989.0
Scott
Quote from: 79 Eldorado on December 25, 2020, 03:11:58 PM
Now listed on our forum here: Scott.
OK, why does the replacement part care about power polarity? The connector
is not really set up to control it. Bruce Roe
Quote from: bcroe on December 25, 2020, 04:06:15 PM
OK, why does the replacement part care about power polarity? The connector
is not really set up to control it. Bruce Roe
The internal controller wires, for the controller I used, were +/- specific. I think it's because the controller needs a very small amount of power to monitor even when it cuts the power to the heating element (around 1/100th of an Amp). I verified which was the supply on the original vehicle wiring if the connector was assembled in the normal position and I assembled the wires accordingly.
The original connector appearance is different from top to bottom but yes if someone twisted the wires inside the TB, pretty easy to do, they could flip the electrical connector upside-down and the terminals themselves would not error proof against it. I suspect if the wires are swapped there would be no damage but instead current would never pass because the controller has no signal to allow power to pass. The prototype controllers were very expensive and I only had 3 so I didn't want to push my luck reversing the polarity when it was clearly indicated.
Maybe I should add a photo which shows which direction the connector should be assembled but probably the best way to ensure the proper orientation is to check the wiring harness for ground with the car off. I didn't try that but I suspect ground will always be grounded.
Scott
Quote from: 79 EldoradoThe internal controller wires, for the controller I used, were +/- specific. I think it's because the controller needs a very small amount of power to monitor even when it cuts the power to the heating element (around 1/100th of an Amp). I verified which was the supply on the original vehicle wiring if the connector was assembled in the normal position and I assembled the wires accordingly.
The original connector appearance is different from top to bottom but yes if someone twisted the wires inside the TB, pretty easy to do, they could flip the electrical connector upside-down and the terminals themselves would not error proof against it. I suspect if the wires are swapped there would be no damage but instead current would never pass because the controller has no signal to allow power to pass. The prototype controllers were very expensive and I only had 3 so I didn't want to push my luck reversing the polarity when it was clearly indicated. Scott
So that brings the question of, what is this controller? Proprietary? Bruce
Quote from: bcroe on December 25, 2020, 05:27:53 PM
So that brings the question of, what is this controller? Proprietary? Bruce
Yes, as I recall they made it a point to say that. I bought it based on specification and I asked a lot of durability and logic questions prior to making the decision. It uses a temperature probe to provide controller feedback. If the probe breaks it's error proofed to not pass power. It's programmable in their production to a set temp to cut power and a second temp to reset. Customizing the range you can basically set-up the device to avoid constant cycling. Since my heat sink has decent mass it also helps keep things stable. I verified with the supplier that it would be capable of many millions of cycles. I would need to dig for my assumptions but I basically determined the cycles with an extreme user. It was something like assuming a person would drive an average of 5 hours a day and 240 days out of the year for 15 years (again I would need to verify what I used exactly). I have it in a workbook someplace. The number of cycles was high but they were not concerned at all by the number.
Scott
Bruce,
I did just verify in the Electrical Trouble Shooting Manual the ground is always grounded. At least on our 1979's the supply wire should be dark blue and the ground is black but of course after 40 years both wires pretty much look the same color so probing for ground with the car off seems to be the best a good solution to make 100% certain the electrical connector hasn't been flipped.
Thanks for the comment. I will suggest how to check it in the installation instructions.
Scott
Quote from: 79 Eldorado on December 26, 2020, 11:08:28 AM
Bruce,
I did just verify in the Electrical Trouble Shooting Manual the ground is always grounded. At least on our 1979's the supply wire should be dark blue and the ground is black but of course after 40 years both wires pretty much look the same color so probing for ground with the car off seems to be the best a good solution to make 100% certain the electrical connector hasn't been flipped. Scott.
How about, check for 12V at the connector pins while the engine is
running? It will not stay on if you just turn on the ignition. There
is continuity to ground through the fuel pumps all the time, not many
ohms different from a short to ground. Bruce
Quote from: bcroe on December 26, 2020, 11:17:01 AM
How about, check for 12V at the connector pins while the engine is running? It will not stay on if you just turn on the ignition. There
is continuity to ground through the fuel pumps all the time, not many ohms different from a short to ground. Bruce
As Bruce suggested that's the best way to be certain. It's actually what I did to check it when I did it myself. I liked the idea of testing for ground with the car off but I wasn't aware of what Bruce wrote about a path to ground through the fuel pumps. I need to see if anything needs to be rewritten in the instructions.
Thanks Bruce,
Scott
A lot discussed but I realized the symptoms of a failing FIV were never really covered...
I mentioned I didn't initially realize my original Bendix/OE part was going bad. I knew it seemed to take a little longer for the RPM to drop than it seemed it should but I couldn't quantify it before all of the testing. When I actually measured it what should have been around 2 to 2.5minutes was 11.5 minutes. I determined that I was only getting partial heating from my OE/Bendix part.
Here are the signs:
-1 Reduces RPM but takes a lot more time than seems reasonable... if you don't wait you end-up shifting into gear at an elevated RPM. That was the problem my car had prior to installing the replacement.
-2 RPM never drops to a reasonable level... Elevated RPM all of the time because the valve no longer closes.. you may notice the car wants to accelerate by itself requiring the driver to tap the brakes. That was the issue Joel Howard experienced.
-3 No high idle RPM... If you have this issue you should check to see if your FIV is "latched" which means the clip has traveled far enough to lock the position of the plunger in the closed position. I recommend removing the clip because the wire is hardened and can be brittle. It seems to only serve the purpose of reducing the "loose" part assembly height to make the FIV easier to install. Cadillac may have done that to help protect the switch arm on the OE part. The replacement eliminated the arm.
My struggling OE/Bendix part wasn't as bad as one which had completely failed but it was still an incredible improvement once I installed the replacement. Because it's not always obvious I was trying to think of a way, probably limited to forum members, to try it before you buy it.
Scott
I'm adding a summary graphic showing a section view of some of the parts relative to each other as well as a graph showing proper operation versus a part I tested where the heating circuit was starting to fail. In this case the FIV was obviously taking too long to close the valve and thus very slow going from "Fast Idle" to stabilized / normal idle.
Scott
That valve should be a great help to owners looking for solutions. I have favored
solutions that replace or plug directly into original equipment, because any custom
work means now only that tech will understand or be able to maintain the system in
the future.
I remember my 79 E running away from me, shortly after I got it. There were plenty
of other issues too. After shimming the valve, I just kept my foot on the gas as
needed cold, and worked on figuring out why the ECU gave the wrong fuel mixture.
Starting cold idle was less a problem for me, I was usually only a couple stop signs
away from the expressway. Never went to the trouble of measuring time.
I have wondered, just how many of those 70s EFI cars are still out there running
fine, and how many got shoved into storage (or worse) because no mechanic knew
how to deal with EFI failures? Any how many repairable 70s ECUs are lost on a
back shelf? It would be good to get them all rounded up, and repaired when practical.
I am hearing about broken 70s EFIs as much as ever, like another car every week.
Previous century as I was starting to get a handle on my 79 details, another Cad
owner pointed out an Evil Bay auction of a lot of some 30 defective 70s Cad ECUs.
I got them at an affordable price, after pointing out that they were just boat anchors
that nobody (at that time) could fix. In time those and some other donations helped
me get on top of the 5 somewhat different years. More recently the Cosworth Vega
entered the picture as a very close EFI relative. Bruce Roe
Quote from: bcroe on January 10, 2021, 02:19:36 PM
That valve should be a great help to owners looking for solutions. I have favored solutions that replace or plug directly into original equipment, because any custom work means now only that tech will understand or be able to maintain the system in the future.
Thanks Bruce.
Quote from: bcroe on January 10, 2021, 02:19:36 PM
I have wondered, just how many of those 70s EFI cars are still out there running fine, and how many got shoved into storage (or worse) because no mechanic knew how to deal with EFI failures? Any how many repairable 70s ECUs are lost on a back shelf? It would be good to get them all rounded up, and repaired when practical.
Between your ECU repairs and my sensors, it seems over some time, we might be able to estimate how many are out there. I've been pretty surprised at the numbers.
Quote from: bcroe on January 10, 2021, 02:19:36 PM
I am hearing about broken 70s EFIs as much as ever, like another car every week. Previous century as I was starting to get a handle on my 79 details, another Cad owner pointed out an Evil Bay auction of a lot of some 30 defective 70s Cad ECUs. I got them at an affordable price, after pointing out that they were just boat anchors that nobody (at that time) could fix. In time those and some other donations helped me get on top of the 5 somewhat different years.
I'm glad those 30 ECUs made it to your hands. My belief is the interest in owning an older vehicle, casual user or collector, has a lot to do with whether or not the particular car can be repaired. If there are no repair parts and no after market support cars tend to die off. Had I lost confidence in that part of it I certainly wouldn't have spent as much time as I did. The knowledge on this forum and the repair work you've done will give people confidence in keeping this era of cars viable farther into the future than would have been possible.
When I was looking for a replacement spindle I saw too many 79-85 Eldorados in junkyards which didn't look like they were that bad when they went it but I don't think I saw any 1979's and I suspect 80-85 are there due, in part, the HT4100 and maybe the newer system being even more of a "black box".
Quote from: bcroe on January 10, 2021, 02:19:36 PM
More recently the Cosworth Vega entered the picture as a very close EFI relative.
Bruce Roe
I know I've mentioned this before but I assumed the sensor technology might be similar. I read a pretty good thread on a Cosworth forum and they explained a different operation but knowing the Cadillac sensor I suspected they may have misunderstood how the sensor(s) function because some of the things they mentioned made me think they were similar. I think you told me once they are not similar.
The special Cadillac diagnostic ECU, Kent-Moore J25400 is also the same part for the Datsun/Nissan "Z" EFI car (capture added in attachment from the Datsun Z forum). The only difference is a different overlay and I think some functions are dedicated to only Cadillac or only the Z. The wiring harness adapters are also different. I have some captures showing the Datsun/Nissan Z overlay and I captured the diagnotic tool manual posted for the Z because at the time I couldn't find the Cadillac instructions.
I'm adding the latest version of my removal/install instructions. I added a page dedicated to verifying polarity.
Scott
From the design I can see, the Cosworth EFI design was first, with the 70s Cad
EFI being a very much improved development of that starting point. Being an
analog computer, they both needed linear temp sensors which could be directly
translated to linear fuel changes. The Cosworth did it using the common temp
curve of a silicon transistor, that sensor had mechanical problems. The Cad
developed a very fine resistance wire sensor, linear enough. But the Cad sensor
also tended to fail open circuit over time. I think Scotts version will prove much
longer lived, years will tell for sure.
Reasons they were not interchangeable, \included opposite sloped curve, different
amount of slope, and mechanically different. Someone asking me about the temp
sensors is how I became aware of the Cosworth design, and I did some support
work including drawings, a temp sensor tester, and a bench ECU tester.
I have pieces of several J25400 sets around here, intended for use on a car. My
testing is on the bench, over a much wider situations than possible on a car, so I
never tried to get a J25400 operational. The Cosworth owners wondered if it could
work for them, because the connectors and many other things are similar to the
Cad. But the connectors are wired completely differently, and things like the temp
sensors make them incompatible.
And I know zippo about the Datsun EFI, wonder how it fits into the above? How do
I get on the Datsun Z forum? Bruce Roe
Quote from: bcroe on January 19, 2021, 01:47:04 PM
...How do I get on the Datsun Z forum?
Bruce Roe
Bruce,
I found it by searching for the J25400 manual. In Google images I saw a lot of scanned pages and they all linked to that site. Because the Datsun Z uses that same J25400 those two systems seem like they must be the closest but that's just a guess. I found it again. Here you go:
http://datsunforum.com/efi-troubleshooting-kent-moore-j25400-analyzer/
If you made a curve for the Cosworth sensor and you know what the sensor should look like, mechanical interface details, I'm pretty sure with enough time I could duplicate it.
It would be really interesting to know how close the Cadillac and Z car systems were. I was shocked when I learned that they used the same tester with just a different overlay and wiring harness adapter. I tried to ask a technical question on Bring-A-Trailer once because there are a lot of Z experts there but they really didn't appreciate a technical question which wasn't specific to the car which was for sale.
Scott
Thanks Scott, I looked over some of the drawings at that site. Despite both using a
J25400 test set, it appears the EFI systems are very different. I would rather have
the Cad EFI than the Datsun. Bruce
Once I realized it was a Z specific manual I never really looked at it closely; just assumed it would be better than nothing if I ever needed it.
After I read your reply I took a look at the temp sensor curve and it's reversed compared to our Cadillacs (Highest resistance at coldest temps for the Z). I guess the J25400 simply read the resistance and it was up to the user to see if the value was correct on the readout for the given temp. So it was easy to combine that test.
Scott
Yea about everything connected to the Datsun ECU is different from the Cad.
Most notable is the mechanical air flap to measure air intake, a crude device
from an earlier generation. Cad used a MAP, partly mechanical, but later made
completely solid state.
I guess the pumps and injectors were the same. Bruce Roe