1991 Chevy Corsica: Starting problems

[annunaki]

Does a '91 even have an OBD system??? OBD as not a requirment back then if I remember correctly. All vehicles from '96 and on had to have the OBDII sytstem on board.

 

[emrliquidlife]

Any update on how it went?

E

 

[TLS Guy]

Oh dear you have had an awful lot of advice.

First off that car does not have distributor, it has distributer less ignition.

I said yesterday these forums were like Click and Clack on Stump the Chump. Now we have the real thing!

You will probably know even they have trouble diagnosing auto problems long range.

However I think the key part of you story is that it always has long cranking time. Also the fact that the longer you leave it the less likely it is to start.

I think the fuel system is depressurising. The fuel rails should maintain pressure between starts. If it does not it makes for hard starting. Faults that cause this are cracked fuel rails, especially Chrysler products, and leaking injector O rings. The latter is especially prevalent on older vehicles. There are many other causes as well.

I suspect you have a slow leak that takes about 12 hours to completely depressurise. Further I suspect the pressure is falling faster on one cylinder bank. When it starts right away, it starts on both banks. In the cold the cylinders that start flood out which is why you have to wait to restart.

Malfunctioning EFI systems certainly do flood out.

There are pressure test ports on the fuel rails, and you can get a fuel rail pressure tester at auto parts stores.

From what you have said, I would do the following.

Check engine codes. That is always job one on modern engines. Even if it does not tell you what the problem is exactly, you very often get steered to the problem.

I would do a fuel pressure test and especially a fuel pressure leak down test.

It is important to get this sorted, as a fault like this has a good chance of being associated with a fuel leak. These sorts of problems have a high association with engine compartment fires.

When you find out for sure what is the matter with your vehicle, I would be prepared to give members the entertainment value of playing "Stump the Chump."

 

[Rickster71]

Does a '91 even have an OBD system??? OBD as not a requirment back then if I remember correctly. All vehicles from '96 and on had to have the OBDII sytstem on board.

GM had a way to pull codes since the early eighties; nothing standardized like OBD-II.

Seth's car has OBD-I
ODB-II started in 1994

 

[Seth=L]

Oh dear you have had an awful lot of advice.

First off that car does not have distributor, it has distributer less ignition.

I said yesterday these forums were like Click and Clack on Stump the Chump. Now we have the real thing!

You will probably know even they have trouble diagnosing auto problems long range.

However I think the key part of you story is that it always has long cranking time. Also the fact that the longer you leave it the less likely it is to start.

I think the fuel system is depressurising. The fuel rails should maintain pressure between starts. If it does not it makes for hard starting. Faults that cause this are cracked fuel rails, especially Chrysler products, and leaking injector O rings. The latter is especially prevalent on older vehicles. There are many other causes as well.

I suspect you have a slow leak that takes about 12 hours to completely depressurise. Further I suspect the pressure is falling faster on one cylinder bank. When it starts right away, it starts on both banks. In the cold the cylinders that start flood out which is why you have to wait to restart.

Malfunctioning EFI systems certainly do flood out.

There are pressure test ports on the fuel rails, and you can get a fuel rail pressure tester at auto parts stores.

From what you have said, I would do the following.

Check engine codes. That is always job one on modern engines. Even if it does not tell you what the problem is exactly, you very often get steered to the problem.

I would do a fuel pressure test and especially a fuel pressure leak down test.

It is important to get this sorted, as a fault like this has a good chance of being associated with a fuel leak. These sorts of problems have a high association with engine compartment fires.

When you find out for sure what is the matter with your vehicle, I would be prepared to give members the entertainment value of playing "Stump the Chump."

When I get the money I will be doing this, that sounds perfect to the situation.

 

[astrodon]

I'll add my 2-cents now. I have owned many Chevys (my dad used to work at the Chevy Tech Center) and have owned a 91 Corsica (it was one of the best cars I have ever owned). From what you described, I would bet that you have a bad solenoid. As I recall, on the 91 Corsica, the solenoid (which engages the starter) sits on top of the starter and you can't get to it without dropping the starter. Usually it is best just to change out the whole assembly (starter + solenoid). Also, get a new one, not a rebuilt one. I would try this before any of the other scenarios described here since it is the easiest and the cheapest thing to try.

 

[TLS Guy]

I'll add my 2-cents now. I have owned many Chevys (my dad used to work at the Chevy Tech Center) and have owned a 91 Corsica (it was one of the best cars I have ever owned). From what you described, I would bet that you have a bad solenoid. As I recall, on the 91 Corsica, the solenoid (which engages the starter) sits on top of the starter and you can't get to it without dropping the starter. Usually it is best just to change out the whole assembly (starter + solenoid). Also, get a new one, not a rebuilt one. I would try this before any of the other scenarios described here since it is the easiest and the cheapest thing to try.

His engine cranks fine. It is nothing to do with the started system. Starter solenoid failures stop the engine cranking. That is just the sort of BS dealers pull. I'm still running my 1988 6.2 lt diesel Suburban. It has around 200,000 miles on it. If had been in a dealership it would have gone through the crusher years ago. I think car dealerships compete for the record in the number of stupid absurd auto fault diagnoses.

 

[yettitheman]

His engine cranks fine. It is nothing to do with the started system. Starter solenoid failures stop the engine cranking. That is just the sort of BS dealers pull. I'm still running my 1988 6.2 lt diesel Suburban. It has around 200,000 miles on it. If had been in a dealership it would have gone through the crusher years ago. I think car dealerships compete for the record in the number of stupid absurd auto fault diagnoses.

I bet that 6.2 is economical on gasoline

I wonder if the Charcoal Canister may be to blame for some of this?? They do function as a return of sorts for excess fuel rail pressure, and typically cars that have been through "a lot" have some "great modifications" to get running again.

Seth, more expensive repairs, but plausible problems:
IAC valve... seems like all 90's IAC's sucked in my experience.
FPR... that would be a fun one to replace... (then again I'm not a Corsica expert, so, no idea where that is off the top of my head)
TPS... even my car had a problem with it and it didn't want to run correctly.

 

[yettitheman]

Other things that may or may not cause the problem (in no order, just stuff I've looked at):
TCC solenoid
Intake manifold gaskets
fuel injectors (Injectors on those engines are problematic too - once warm, they too will loose their resistance and kick the QDM (quad driver module) off, causing a no-start condition and often won't set a code, but can burn up the o2 sensor) The "Quad Driver" is a device in the computer that "drives" electro-
mechanical devices in the car. Basically, similar to how a relay works for high load switch control with low level control input.

Nothing else right now except this:
http://youtube.com/watch?v=ApXSmGacxHA&feature=related

 

[TLS Guy]

I bet that 6.2 is economical on gasoline

I wonder if the Charcoal Canister may be to blame for some of this?? They do function as a return of sorts for excess fuel rail pressure, and typically cars that have been through "a lot" have some "great modifications" to get running again.

Seth, more expensive repairs, but plausible problems:
IAC valve... seems like all 90's IAC's sucked in my experience.
FPR... that would be a fun one to replace... (then again I'm not a Corsica expert, so, no idea where that is off the top of my head)
TPS... even my car had a problem with it and it didn't want to run correctly.

Yes, it could be the purge system. That should show on the codes, which is why checking them is job 1.

 

[Sheep]

Does a '91 even have an OBD system??? OBD as not a requirment back then if I remember correctly. All vehicles from '96 and on had to have the OBDII sytstem on board.

OBD-0 my friend. If there is a CEL, you need to jump 2 wires(Don't know which, Car forums help here) and check the ECU LED (at least that's how it works in OBD-0 Honda's).

Malfunctioning EFI systems certainly do flood out.

Yeah, but I can press my gas pedal all I want, it's not going to flood (which is what was being implied).

I think car dealerships compete for the record in the number of stupid absurd auto fault diagnoses.

I work at a Toyota Dealership. I have never seen a mis-diagnosis that wasn't fully covered by our dealership. Way to play up the stereotype.

I bet that 6.2 is economical on gasoline

It's a Diesel.

Intake manifold gaskets

Intake system leaks would cause idle surge, not no start.

In unrelated news, my cars new ECU finally arrived and it runs like a charm. Just need to tune it and throw it on the Aircare machine.

SheepStar

 

[codyman242002]

Wow!

Hi i have same car, and problem. ive been researching and am mechanically inclined. i tested the fuel pressure, coils on "DIS" , checked engine codes (none). now the only awnser that makes sense is that the crank sensor is magnetic and it should be cleaned or replaced. I'm about to try this now, it may be the answer, but im not sure where it is. Good luck.

 

[TLS Guy]

Hi i have same car, and problem. ive been researching and am mechanically inclined. i tested the fuel pressure, coils on "DIS" , checked engine codes (none). now the only awnser that makes sense is that the crank sensor is magnetic and it should be cleaned or replaced. I'm about to try this now, it may be the answer, but im not sure where it is. Good luck.

It's right down by the belt pulley. That problem should show on the codes. Also if it is bad, when the engine cranks and does not start there will be no spark and no fuel injector pulse. Did you test to see if the fuel pressure leaks down after shutting off the engine? The pressure should hold between starts.

 

[yettitheman]

Well, me and Seth worked on his ride yesterday
Changed the oil with the filter, air filter, spark plugs and the wires in about 4 hours... yes, 4 hours because the wires and plugs SUCK to get to.

The car is definetly smoother running and efficiency is increased big time.
However, we do not know as of yet if that was all of the problems or not.

Air filter was nice and black

Oil and filter, well, they were just old and needed changed.

The plugs and wires, were original AC/Delco plugs. Gap was .060 (which stock gap needs to be .045 ) and the electrode was rounded over while the strap was worn away from age. A little white on the plugs, but other than that, condition of the plugs were normal.

No codes were set in the computer, which was good as well.

Next time I'll be looking at the pressure at the fuel rail to see if the pump is indeed still bad.

 

[Seth=L]

Indeed Mr yetti, and many thanks for your help. I owe you a beer or something of equal value, like a cat or hampster.

 

[yettitheman]

Indeed Mr yetti, and many thanks for your help. I owe you a beer or something of equal value, like a cat or hampster.

I don't want no damn "hampster".. or a hamster or a cat...

Pizza and beer sound good though