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chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL

91 GrandAm 2.5l Stalling

Ok, I need your assistants,
Currently have a 1991 Grand Am 2.5l. This car is currently stalling when warm and will not restart until cooled down.

Things I have replaced because of age of parts or corroded
Coolant temp sensor and thermostat, IAC - throwing code, 2 vac hoses - dry rot,
I have replaced Fuel filter and pump - both were original, I also replaced the ICM per a mechanic which was thinking that as going bad and over heating. I have also flushed the radiator and engine. I also checked the fuel pressure regualar diaphram which looked brand new

It seems like with or with out the thermostat in, the car will work it was up to 220, then fan will kick in for a few seconds then stall. I am thinking possible vapor lock but i am not sure, could it possible be a faulty fuel injector to the throttle body?

And help with be greatly appreciated
Thanks


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3


Well I could list ten things to replace that "may" be the problem, but to properly repair it you need to diagnose it by gathering some information. Most importantly you need to determine if you have lost spark, fuel pressure or both. So, you need to have a fuel pressure gauge attached when the problem happens, and a reliable way to test for spark, preferably a spark-indicator plug tool if at all possible. With that information at hand, you can start narrowing down the possibilities, which right now are many.

You said you replaced the "ICM"; do you mean "ECM" by any chance?

Also, I find it unlikely to be vapor lock, as that is next to impossible with a pressurized fuel line.

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
said by mattmag:

You said you replaced the "ICM"; do you mean "ECM" by any chance?

ICM, Ignition control module

Yea, I guess I will run over to harbor freight and get a pressure gauge or wait till this weekend and have my neighbor look at it is he is free... Thanks Matt


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

OK, that one confuses folks sometimes. Actually there is a fairly good chance the issue is in the ECM, but try and do the other diags first.


dennismurphy
Put me on hold? I'll put YOU on hold
Premium
join:2002-11-19
Parsippany, NJ
kudos:3
Reviews:
·Verizon FiOS
reply to chigowolfs
I had an '86 Grand Am with the same exact engine and same exact symptoms. I never could figure it out.

My suspicion is that it was a leaky TBI but I'm not really sure. If you play with the gas enough when it's warm you can prevent the stall out and then get it running. Once it stalls though, you're stuck for 25-30 minutes.


dennismurphy
Put me on hold? I'll put YOU on hold
Premium
join:2002-11-19
Parsippany, NJ
kudos:3
Reviews:
·Verizon FiOS
reply to chigowolfs
From Wikipedia:

"Inspection (and replacement, if necessary) of the MAP sensor, and its accompanying vacuum hose, is often a solution to many driveability problems. This sensor largely controls the engine's driveability. Stuck EGR valves are also very common on the Tech IV."

Tig

join:2006-06-29
Carrying Place, ON
reply to chigowolfs
Describe the stall please. Die, stumble, fade? Can you coax along for a bit? Any dash codes at all?
I had an 83 Cavalier that would just die when warm. 20 mins later it would start and run until it was warm again, then die. No codes posted at all. Using a scope, I found that the crank signal would get weak and drop out. Car would die. Inspection found a crack in the sensor housing.

rody_44
Premium
join:2004-02-20
Quakertown, PA
reply to chigowolfs
Your vehicle has one of the earlier passlock systems. Ide look into that as a possible source of your problems. With a passlock problem the car usually has fuel pressure spark and all. On shutdown it generally shuts off like you turned the key off.


BK3

join:2001-04-10
Geneva, IL
reply to chigowolfs
The crankshaft sensor is a very real possibility, given what you have described.

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
reply to Tig
said by Tig:

Describe the stall please. Die, stumble, fade? Can you coax along for a bit? Any dash codes at all?

It just dies like you turned off the key. When watching the TBI, seems like nothing is coming out once it dies.... This is become more and more a mystery. No codes are being thrown at all.

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
reply to rody_44
said by rody_44:

Your vehicle has one of the earlier passlock systems

This started in the 96 grand am... But 91 roadmaster. No it idoesnt has a passlock system on it


Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18
reply to rody_44
said by rody_44:

Your vehicle has one of the earlier passlock systems. Ide look into that as a possible source of your problems.

It only prevents starting if the proper PL/VATS info is not received. It cannot shut down or stall a running engine. That is not how it works.

Details here:

How To FULLY Bypass VATS PassKEY and Passlock Systems in GM cars
»newrockies.com/
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rody_44
Premium
join:2004-02-20
Quakertown, PA

1 edit
I disagree it cant shut it down. Seen it in two Different vehicles. Both newer tho. seems the older ones dont act the same way.

Tig

join:2006-06-29
Carrying Place, ON
reply to chigowolfs
said by chigowolfs:

said by Tig:

Describe the stall please. Die, stumble, fade? Can you coax along for a bit? Any dash codes at all?

It just dies like you turned off the key. When watching the TBI, seems like nothing is coming out once it dies.... This is become more and more a mystery. No codes are being thrown at all.

Just realized it was my 90 Corsica (not the Cavalier) that did exactly that. I went through a detailed process to come to the crank sensor. Schematics, data sheets, oscilloscopes as well as knowledge of inductive sensors. Bottom line for the Corsica was the raw signal level would start around 1.5 Vpp and I could watch it fade as the engine warmed up. I stuck a pin through the sensor wire to creat a test point. The engine would die when the raw signal reach about 1Vpp. After a 10 or 20 minute rest it would start and the singal would be stronger, but again would fade. A bit of research revealed that there was no code on that vehicle for crank sensor faults. Service guide flow chart for "engine dies" was a very expensive list of parts that included Ign pack, ECM, etc, etc... Inspection of the crank sensor revealed a suspicious crack. I replaced it.
I hope this is somewhat helpful. If you're going for a DIY repair, find a U pull it, wrecking yard. Sensor should be less than $5.

Edit; the Corsica also had the 2.5l engine. My arm was just long enough to reach the sensor from the top drivers side by the firewall. I still have the factory service manual if you think of anything you'd like me to look up.

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
This is what I am starting to lean towards as well. My neighbor has the car right now (since yesterday) checking it out. A new sensor is only $16 at the part store. less aggravation then having to pull it of a junker and replace it.... I dont know, we will see what he says, maybe I will be luck and he will swap it out already.
All I know, after replacing the parts I have already mentioned it runs like a champ when it does run... Car only has 83k miles on it, its my fathers... The things I do for them HA!


linicx
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United State
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reply to Tig
I had an old Pontiac that did that years ago. The last time I had it in the shop it died two miles after I picked it up and was on my way home. They towed it back and about a week later I learned the "sock" in the gas tank was filled with sand. They said it came from dirty gasoline. The "sock" was changed, the tank was removed, washed, and reinstalled. I never had any other problems, and I sold it four years later.
--
Mac: No windows, No Gates, Apple inside

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
said by linicx:

I had an old Pontiac that did that years ago. The last time I had it in the shop it died two miles after I picked it up and was on my way home. They towed it back and about a week later I learned the "sock" in the gas tank was filled with sand. They said it came from dirty gasoline. The "sock" was changed, the tank was removed, washed, and reinstalled. I never had any other problems, and I sold it four years later.

I just replaced the fuel pump, the sleeve was clean so was the inside of the gas tank. I am really leaving to electrical/ sensor issue.


linicx
Caveat Emptor
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join:2002-12-03
United State
Reviews:
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·CenturyLink
Whatever the problem with your car ultimately is, I hope it is easy on your wallet. The mechanic who worked on my Pontiac said the sock problem wasn't very common, but it did happen from time to time. I did a lot of interstate travel then due to family. I was lucky it didn't die in the middle of St. Louis during rush hour.
--
Mac: No windows, No Gates, Apple inside

Tig

join:2006-06-29
Carrying Place, ON
reply to chigowolfs
Any updates?

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
reply to BK3
said by BK3:

The crankshaft sensor is a very real possibility, given what you have described.

BK3, congrats you win the prize.. there as a crack down the length of the crankshaft sensor

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
reply to chigowolfs
Click for full size
It ended up being the crankshaft sensor.... beautiful crack down the length of it , so far seems all is good with it

Tig

join:2006-06-29
Carrying Place, ON
Wow, that's more than 10 times the size of the crack that shut me down.
Glad to hear she's fixed.

chigowolfs
Wolfie Is Here

join:2003-04-18
Chicago, IL
Thanks Tig,
It is absolutely amazing that this part caused confusion wise. From only being about to idle about 15 minutes, making it look like a bad thermostat ( with temp raising to 220) to making it look like a bad fuel filter or pump. Stupid $16.00 part no one would ever think about looking at. I personally will stick with new cars that has a just about a sensor on everything that throws a code LOL
My father is happy that he has is car back. I went with him on a 45 minute test drive, everything is good. Now just have to replace antifreeze and his car (currently running water as a test bed) should be good for another 83k miles LOL


Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18
said by chigowolfs:

It is absolutely amazing that this part caused confusion wise. From only being about to idle about 15 minutes, making it look like a bad thermostat ( with temp raising to 220) to making it look like a bad fuel filter or pump. Stupid $16.00 part no one would ever think about looking at.

Slight correction, but a scanner would have shown that sensor needing replacement if you had used one. A crankshaft position sensor is a very common replacement when the live data stream shows it is failing/failed.

This would have also helped pinpoint the cause.

»www.ebay.com/itm/like/2212774995 ··· ?lpid=82
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?

Tig

join:2006-06-29
Carrying Place, ON

1 edit
Unless things changed between 90 and 91 a scanner won't read the sensor or show that it needs replacement. It can only present an ECM processed value for engine RPM, but that can be gated for various reasons as explored in service guide chart A3, Engine cranks but won't run. There is no code for crank sensor problems.
First line in A3 says, among other obvious things, check fuel quantity. Chart A3 then checks TPS, coolant sensor and RPM. Assuming no RPM, a four step process eliminates ignition components and wiring. In the end, you measure the raw sensor with a DVM.
Even in hindsight, there is no short cut to this fix.


Doctor Olds
I Need A Remedy For What's Ailing Me.
Premium,VIP
join:2001-04-19
1970 442 W30
kudos:18
said by Tig:

Unless things changed between 90 and 91 a scanner won't read the sensor or show that it needs replacement. It can only present an ECM processed value for engine RPM, but that can be gated for vatious reasons as explored in service guide chart A3, Engine cranks but won't run. There is no code for crank sensor problems.

The ECM will not show a imaginary signal when the sensor is not outputting a signal. That is exactly why it shuts off.
said by Tig:

First line in A3 says, among other obvious things, check fuel quantity. Chart A3 then checks TPS, coolant sensor and RPM. Assuming no RPM, a four step process eliminates ignition components and wiring. In the end, you measure the raw sensor with a DVM.
Even in hindsight, there is no short cut to this fix.

No one claimed there were any shortcuts that I've seen in this thread.
--
What’s the point of owning a supercar if you can’t scare yourself stupid from time to time?


mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
kudos:3

1 recommendation

reply to Doctor Olds
said by Doctor Olds:

A crankshaft position sensor is a very common replacement when the live data stream shows it is failing/failed.

Live data stream? From a crank sensor? In 1991? Doc, what are you smokin' today?!

Best one can hope for on that vintage is to hook up a lab scope and watch the waveform. You surely aren't going to see anything with the almighty (and over-abused) scan-tool in this case.

And yes there are all sorts of shortcuts in this thread and most others. I get weary of trying to suggest proper diagnostics, only to be followed up quickly with "Well I had a car the same color as your's and it needed a new widget" so the OP goes and buys a new widget and that isn't it. So he goes to the next guy that knows a guy with the same problem and low and behold that doesn't fix it either.

After enough parts-changing, not analysis or diagnosis, the faulty part is stumbled upon and that makes the last guy's guess heroic.

Could I list a whole crapload of parts that "may be it"? Sure could, but that is useless conjecture.

Tig

join:2006-06-29
Carrying Place, ON
reply to Doctor Olds
My point was, the scanner will not "show that sensor needing replacement"