1980 Eldorado 368 engine,resume from Italy

[chevy350]

Maybe is not to load to hear but to be sure ,I unscrew the fuel canister from the "base" turn the key and I have fuel on the floor.
Starting from canister the fuel line is made from steel,the inlet section on the body is steel too,there is somewhere a rubber hose?
This think is tragicomic 
I can understatnd the way to follow !
Cranking the car the sound is really smooth.

[chevy350]

I decided to take off some dust from engine bay,I checked the valve train too to find some sludge,but fortuntely I found just oil.
I clean the air filter cap,is really horrible the grey color.I take off the paint jut using the old gasoline from the tank,is not perfect but is the stock color with sign of the times.

[TJ Hopland]

The sending unit inside the tank has metal lines on it.  The fuel pump is connected to one of those lines with a very short piece of hose.   With some age its common for that piece of hose to split or even completely disintegrate.  Since its inside the tank you don't get a visible leak just no fuel pressure.     

[chevy350]

The sending unit inside the tank has metal lines on it.  The fuel pump is connected to one of those lines with a very short piece of hose.   With some age its common for that piece of hose to split or even completely disintegrate.  Since its inside the tank you don't get a visible leak just no fuel pressure.     

Ok I understand,but if the the piece of rubber hose is gone I don't have at all the "squirt"  of gasoline in the fuel filter !
Is correct what I'm sayng?

[bcroe]

Here is my 79 tank unit with failed hose from pump to pipe.  Bruce Roe

[chevy350]

Thank you Bruce !
I'm going to unveal the mistery...I'm just stupid ,I unscrewed 3/4 times the wrong tube..the vacuum for the brake booster...
What a shame.
Then I find the correct one with the bleeder,I used the bleeder to take out a lot of air trapped in the hose until the fuel come out.
Now I'm sure the fuel pump work correctly(I take my shower with fuel .I checked the injector but the fuel don't come out,so I presume they are dirty/clogged.
I think I can clean by my self,correct?

[TJ Hopland]

It would be pretty rare to have both injectors clogged to the point no fuel comes out.  Fuel doesn't enter in one tiny area like a port injector, these have an inlet all the way around their fairly large body with a screen so it would take a lot of stuff to completely clog both of them.  More likely they are not being told to operate.  Can you hear the injectors clicking?   This style you can usually hear them clicking if you have the lid off the air cleaner. 

[chevy350]

No sound from injector.
I need to check if in the cable I have voltage and check the fuse too.

[TJ Hopland]

I don't have a manual handy but typically the + is constant from a fuse and the - is what the computer modulates to operate the injector. 

Do you still have a good steady spark at the plugs?   The computer gets its signal that the engine is turning from the distributor.   The internal pickup under the rotor sends a signal to the internal module that is also under the rotor.   In normal mode that pulse signal for every cylinder ready to fire is sent to the computer.   The computer then uses that to figure out when and for how long to fire the injectors as well as send a signal back to the distributor module to fire the coil.  If that when to fire the coil signal gets lost but the engine is still turning there is a default mode that will still fire the coil as an emergency mode so we can't be 100% sure that if there is spark that the computer knows the engine is turning but if we don't have spark we can be pretty sure there is a problem and the computer may not know the engine is turning.   

[chevy350]

Thanks a lot for thr help !

I'm going to understand how to test every single component.
I have the "Electrical Troubleshooting manual"
I'm start from there.

[chevy350]

Reading the manual I see there are many wire signed how "test wire" for example in the TPS is a blue wire.
How I can test it? I need a special tools or just a tester .

I can chek too the ECU?

[TJ Hopland]

There were often car or brand specific test kits that would plug in between the harness connector and the sensor that then had terminals you could connect various test equipment to.   I would expect those to be difficult to find today especially since I think connectors was one thing that changed after the 80/81 models.  An 82 had the same connectors and many sensors that were used through the 1990's. 

If the book is asking for volts or ohms you can use a typical electrical tester.   If it says us J-1234 tool you may not be able to do that test.  The J- tools were the custom made tools that the dealers and some repair people had.   If its a test you really think you need to do its worth searching that part number to see if there are any of those tools available or if someone has come up with a way to simulate one.   I have got lucky both ways.  One time I found someone selling the real tool locally cheap and the other time I found a you tube video on how to build the tool from easy to find modern parts.

If these are similar to the weatherpack connectors they used later you can often partially disassemble the wire end enough to be able to stick typical electrical probes in from the wire side and make contact with the connectors.  It just takes time and there could be risk of damaging now brittle plastic connectors.

I'm not a huge fan of the concept and know nothing of this brand or vendor just using it as an example of the type of tool I am talking about.   They are basically a reasonably fine sharp pin that pokes through the insulation and into the wire.  The down side is it leave a hole in the insulation that could start corrosion and with a low quality tool or rough user can really damage the wire.
https://www.amazon.com/kweiny-Electronic-Piercing-Automotive-Diagnostic/dp/B07DMT6R68/ref=asc_df_B07DMT6R68/?tag=hyprod-20&linkCode=df0&hvadid=312142020868&hvpos=1o5&hvnetw=g&hvrand=5791773861216850127&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9019596&hvtargid=pla-584425445489&psc=1

[chevy350]

I usually use a tester,I'm more confidential with it.

On my shop I have an ultrasonic washer machine,I think is a good idea to use it of course with out O-ring.

But I think is better to have the trottle body repairing kit.

[chevy350]

Hi guys,

i need your help again,how many volt the injector need to work?

I have tested the reistance(ohm) in both I have 1.2 ohm it is correct?

I'm asking because I'm going to test by my self  and I don't want to burn it.

Thank you.

[chevy350]

Hi,

today a little step further,I checked the injector fuse and are ok,I disconnected the 2 connectors from the coil and tested the ground,in the single connector I have 12.700 ohm.

Then I test if the ignition module is ok taking out a sprk plug,connected with is spark plug wires and,using a jumper cable,I connected the base to negative batterie pole,crancking the engine I can see the  spark.It's not a blast but I'm using a 45 ah batterie for test .

I think I need to move in the injector area to found the problem.

I want to say sorry for my english,isn't easy to try explane the problem some time !

[TJ Hopland]

I think if you hook one side of your meter to ground then check the injector connectors with the key on you should read 12v.  The ground comes from the computer and its a modulated signal so a typical volt meter isn't a good tool to test for function.

Looks like I will have to dig out my 80 manuals.  May take some time, have not seen them since before my last move.  I need to see what diagnostics are available in the system.  I want to know things like does it see the engine turning and does it think its firing the injectors.   I don't recall seeing data like that available but I don't think I have looked before.   

[chevy350]

I think if you hook one side of your meter to ground then check the injector connectors with the key on you should read 12v.  The ground comes from the computer and its a modulated signal so a typical volt meter isn't a good tool to test for function.

I have only 0,02 volt using the batterie ground with the keys on and I can hear a sort of "big click in the cab on passenger side where he ECM is located.
I found the ECM hanging under the dash just with wire . Fixed !
Turning on the key in the climate control panel I read 88 and 90,this evening I check the manual for references.

[chevy350]

The fun factor when you work under the dash and lay down on your back,you have a lot of room in the corvette isn't just the same....

[TJ Hopland]

Having the computer connected will likely help.   It falling down likely means this car has had issues for a while and someone was blaming it for the issues.    Even with this being the very first production digital fuel injection system I still don't think the computer itself is or was usually at fault. 

Electrical connectors was something I do remember reading was an issue with the 80 and 81 systems and they changed the design of many of the connectors starting in 82.   Any connector that you can easily access I would take apart and inspect and clean as needed.   Moisture getting in and corroding was the issue. 

[chevy350]

I read the manual to understand the fault code,maybe I read the outside temp...and it's possible 88°F are 31 °celsius,some time I make confusion with conversion,sorry.(today I read 78,25° celsius are correct.

I check in the fuse box the injector fuse,with the key on I don't have voltage,crancking the engine I read 7.9 volt in both.I want to do same think in the terminal wires of each injector crancking the engine but I need an helper.

Under the dash the wires are unmolested,brand new,no bubba work in the way !