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Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Barry M Wheeler #2189 on November 14, 2017, 08:03:33 AM

Title: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 14, 2017, 08:03:33 AM
I got the new battery in the Seville and some gas (Sure hated to hit that "premium" button), but it still won't start. It will cough once but that's all. Lars thinks it may be the computer. I've gone to the site that has the codes and found out "how to read them," but just got up and it's still not full light out. I thought I'd mention the problem and maybe get some hints on how to proceed from here. I still think it's  pretty, but...
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 14, 2017, 08:21:57 AM
Fuel pump maybe?
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 14, 2017, 08:48:58 AM
Could be. I'm not smelling too much gas from pumping the pedal. Also, even just sitting, I wouldn't think the computer would go out with that low a mileage. It's supposed to have always been garaged. There is definitely a "zero" in front of the "one" on the odometer. I'm going to go down to the repair shop in town in a few minutes and get it "in line" for repair. The guy's dad runs a body shop next door and can tow it. (I borrowed his battery lifter yesterday and he wanted to take a look at it anyway..." )
Title: Re: 1991 Seville won't start...
Post by: smokuspollutus on November 14, 2017, 08:59:23 AM
I have never seen a computer really fail on a GM car with digital injection. Sure have heard a lot of mechanics try and blame them for a problem they're unable/unwilling to diagnose further though.

Fuel pressure on this port injection car is very easy to test, as I recall the test valve is on the passenger side of the engine. If it is pumping, you won't smell the gas like you would on a carbureted or TBI vehicle.
Title: Re: 1991 Seville won't start...
Post by: TJ Hopland on November 14, 2017, 10:08:28 AM
Computer failures are pretty rare so I would not go there yet.

If the fuel pump is running I would expect some sputtering even if the pressure was low.     Pull the vacuum hose off the fuel pressure regulator and check for signs of gas.  Its at the end of the fuel rail.  Any signs of gas its shot and likely flooding the engine.    To start a flooded engine hold the gas pedal to the floor.  On 95% of EFI systems that signals the computer to shut off the fuel.

Try a small shot of starting fluid or some gas down the throttle body to see if it fires.  That will tell you if you have spark.   Remember this has a distributor so cap and rotor need to be checked. 
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 14, 2017, 10:29:03 AM
I did try some starting fluid the other day and think there was some firing. This was before I had the new battery in it. I'll try that again in a little bit. Thanks to all for the ideas. BW
Title: Re: 1991 Seville won't start...
Post by: TJ Hopland on November 14, 2017, 10:37:32 AM
May be worth checking to see if your local parts store has a fuel pressure tester in their loan a tool program.  With age there are all sorts of things that can screw up the fuel pressure.   One thing I have heard more lately is there is a short piece of hose between the pump and sending unit.  Apparently with age these can crack and bleed off fuel pressure.    Some styles of injectors won't run at all if the pressure is low but these usually will dribble some.   A pressure gauge will tell you for sure.    I would guess these are at least 50 psi.   IF you are only getting 15 there is your problem. 

Once its running check the oil close.  If it was flooded you may have got a lot of gas in the oil and will want to change it. 



 
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 14, 2017, 01:01:09 PM
Get someone try and listen to hear the fuel pump while the ignition is turned on (RUN position - not start). If you're not getting the psssssst sound, the pump is probably bad but additional testing should first be done to verify the problem is not elsewhere before pulling the tank.
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 14, 2017, 02:29:57 PM
A question for you guys. On a whim, I took the cover from the fuse/relay box under the hood. Check the label on the inside of the cover and it shows both orange 7.5 fuses that are marked "INJ." And in the picture of the actual fuse box, one is missing. Should there be both of them there and could that be part of my problem? As "dumb" as I am, I would think that INJ stands for "injector." You can see the letters if you enlarge the screen a little.

We just went out and Gay listened at the back for any bzzzzz. She didn't hear anything.
Title: Re: 1991 Seville won't start...
Post by: smokuspollutus on November 14, 2017, 06:17:25 PM
Yes Barney, you should have both fuses. The injectors on the PFI cars were known to fail in the early years, likely the fuse had blown because an injector is bad on that circuit, if you can't notice any other obvious sources of a short. In any event, you first need to figure out if you have fuel pressure at the rail, and if so, how much. Given the low mileage (checked out the pictures by the way, nice car!) we could also have a supply problem from old gas deteriorating the rubber pickup hose or sock. Lets try to not drop the tank if we don't have to though. Remember, the tank on this car is not out by the back bumper, but more towards the center of the car, maybe your wife was listening in the wrong place.
Title: Re: 1991 Seville won't start...
Post by: TJ Hopland on November 14, 2017, 06:20:21 PM
Can you see if there are pins in that fuse socket?  If so maybe there should be a fuse in there.   The did sometimes fuse the injectors in banks so it could be an even and odd bank on each fuse.   If there isn't pins in the socket then its likely the label was left over from an earlier version.

You should hear the fuel pump especially if someone is near the back of the car.   When the key is first turned on it should run for at least 3 seconds before shutting off.   No noise its not working.  There should be a relay for it. You could look at the picture of the contacts and put a jumper in the socket to connect the correct 2 pins and see if it runs that way but its likely that the issue is on the pump end not the computer end.

You can also try smacking the bottom of the tank and cycling the key but if it was towed there it should have got rattled around enough to shake loose if it was just slightly stuck. 
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 14, 2017, 06:26:02 PM
Yes there are definitely contact points in the location for the second INJ fuse. The fuse was removed for a reason. What concerns me is why.
Title: Re: 1991 Seville won't start...
Post by: TJ Hopland on November 14, 2017, 06:36:58 PM
Now that others are mentioning it I do remember hearing about issues with some injectors GM was using it having issues especially when ethanol started appearing in the early mid 90's.   The insulation on the internal windings was breaking down and they were shorting out.

You may have more than one issue going on there, you may need a fuel pump and injectors. 

The fuel rail isn't too bad to remove on these and its good to change the O rings anyway.    While its out be sure to replace the fuel pressure regulator and might as well do the valve cover gaskets since they will be easy to access with the fuel rail off.   The gaskets on these are like a giant O ring that fits in a groove so no big deal and the old ones do get crusty.   
Title: Re: 1991 Seville won't start...
Post by: The Tassie Devil(le) on November 14, 2017, 07:07:03 PM
Maybe you should have asked for a further reduction in price, as the seller must have known there was a problem.   Could be a simple problem, or a major one.

Bruce. >:D
Title: Re: 1991 Seville won't start...
Post by: 35-709 on November 14, 2017, 09:30:11 PM
I have a great affection for carbureted engines.  Wouldn't touch a 26 year old fuel injected system for anything, life's too short.   ;D   
Title: Re: 1991 Seville won't start...
Post by: gkhashem on November 14, 2017, 11:44:24 PM
Barry

As I mentioned to you to consider on 1991 4.9L engine, the original GM fuel injectors were a poor design. GM replaced the originals with AC Delco 217296. I cannot find a reference to this online now. (Rock auto now has AC Delco 19244621 as a choice now)

I do remember this as absolutely true. My 1991 Eldorado had the originals fuel injectors in the car, 2 cylinders were poor, 2 were impaired and only 4 were working correctly. It showed up as roughness upon hard acceleration like an alignment issue. It was amazing the car ran as well as it did.

I would also pull and look at the spark plugs since 4 of mine were fouled on a 27000 mile car.

Just a thought and I hope this is not your issue since this is a very expensive fix.

Title: Re: 1991 Seville won't start...
Post by: gkhashem on November 15, 2017, 08:26:34 AM
Quote from: 35-709 on November 14, 2017, 09:30:11 PM
I have a great affection for carbureted engines.  Wouldn't touch a 26 year old fuel injected system for anything, life's too short.   ;D

Not a big deal on these cars, maybe on a 40 year old 1970s Cadillac may have more issues. The more recent cars are much more reliable and repairable.
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 16, 2017, 09:42:44 AM
Last night, I was cruising the "other" Cadillac forum and found several references to problems owners were having with INJ blown fuses. I think the consensus was that injectors getting clogged due to "in town" type driving may contribute to the problem. One person was driving his wife's '91 Eldorado and decided to stomp on it and the car started to object.

I printed out the appropriate pages for my mechanic to use if he wishes and have a shop manual "on the way." And as soon as I finish my coffee I'm going to the county seat and pick up a handful of 7.5 AMP fuses and see what happens if I install a couple of fresh ones.

There was also mention of the ICU going bad. I haven't mentioned that there is no radio in the car. I found a bill for installation of a Kenwood unit in the glove box. Evidently the last owner took it back out and sold it. Would there be some of the electronics used in the radio circuitry that is needed to run the car? (I'm knowledgeable enough to be dangerous...) And, they have one of those remote starter/lock gadgets installed.

I appreciate all the comments and help you guys are giving me. Thanks again. I'll let you know if the fuses let the car start.
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 16, 2017, 10:45:30 AM
The radio doesn't factor into any of issues at hand.

I did notice the car is equipped (or was) with Bose system. Each of speakers in this system are self-powered by an individual amplifier built into each speaker. When one or more of the amplifiers fail, many people simply buy new conventional (non-powered) speakers which is the case here. When this change is made, the original Delco/Bose head unit cannot be used as it lacks amplification circuitry needed to power regular speakers.

Personally I would have chewed this guy up one side and down the other for being such a miserable cheapskate in harvesting the radio before offering the car for sale.

Under the circumstances Barry, I'd call that [insert expletive here] on the phone and politely detail the travails you're experiencing, your disappointment on the point of the complex radio issue that was not disclosed and see if you can get him to send the radio back as the wiring was already done to fit that particular unit (and presumably working with the speakers).

Of course, the possibility exists the replacement radio never did work because whoever did the installation was unaware of the special nature of the Bose System and that is the real reason it was removed prior to the sale. 
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 16, 2017, 12:28:18 PM
The invoice was in the car and his dad paid almost a thousand dollars for the installation, too. I have noted that I need a Bose unit to put back in the car, but I want to get it mobile first. The speakers in the door do not look like they were altered. I'll go over the invoice again and see what they did.
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 16, 2017, 12:36:36 PM
Door speakers are absolutely aftermarket.
Title: Re: 1991 Seville won't start...
Post by: Barry M Wheeler #2189 on November 16, 2017, 02:48:31 PM
I had to go back out in the cold to check. I was fooled by the Bose plate in front of it, not ON the speaker. So when I replace it, get a GM radio that is not a Gold Bose system?
Title: Re: 1991 Seville won't start...
Post by: Eric DeVirgilis CLC# 8621 on November 16, 2017, 03:03:50 PM
Correct.

May have to some detective work on how they have the system (re)wired.
Title: Re: 1991 Seville won't start...
Post by: smokuspollutus on November 16, 2017, 05:38:12 PM
Barney, I suggest that you investigate what sort of butchery was done to the speaker pods themselves. If the Bose hardware is still inside and they didn't totally wreck the pod screwing the speaker in, the amps can be rebuilt fairly inexpensively from a service or really inexpensively if you know what you're doing with capacitors and a soldering iron (I, for one, do not). The Bose speakers themselves are still good, they last forever. Properly working, it is a really great system, definitely worth salvaging if it all feasible.