Car stalls when it warms up

1991 CHEVROLET CORSICA
16,000 MILES
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Car - 91 Chevy Corsica 3.1 (160,000 miles)

Problem - Car struggles (no power), bucks and eventually stalls on inclines. If I wait about an hour, it will starts up OK and runs until it warms up.

Then it starts all over again - No power when I hit the accelerator while climbing up a hill or navigate steep country roads.

My speed drops down to 35-45 an hour, and stalls if I try to go any faster.

Garage work done:

The Check Engine Light was on - Replaced 2 of the fuel injectors, the Cat (old one was clogged) and EGR value.

I was told the other 4 injectors were tested and were OK.

It ran great for about a week before same problem came back. Note: The check engine light did go away, but someone told me it was probably reset. Not sure.

I had another mechanic run extensive diagnostics (with the car on) with a expensive meter. He was able to duplicate the stalling. The only error code from the scan pointed to a bad ignition module.

It was replaced, along with all the coils.

The problem did not go away.
---------------------------------------------------
Other things replaced or tried:
Map sensor
Crank sensor
Coolant temp sensor
New spark plugs and wires
Fuel injector cleaner additives
Fuel pressure was checked - it's good
-----------------------------------------------------------------------

I'm a big fan of your web site; so I'm hoping you might be the one to figure this out.

I'm a senor, living on a very fixed income and I need the car to get to my job.

Without the car I can't make enough to fix the car properly or get another.

Do you have any thoughts on what the problem is and what I can try?

I've exhausted all my funds trying to fix the problem.

I've gone through 5 different "street mechanics" and no one seems to have a clue.

Please help me

Thank you,

Rob
Aug 14, 2012 at 5:14 PM
Advertisement
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Since problem is engine temperature related, I would suggest checking the ECT.
Aug 14, 2012 at 5:36 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Not sure if you mean the Coolant Temp sensor; if so, it has been changed.
Aug 14, 2012 at 6:12 PM
Advertisement
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Sorry I missed that out.
Presently are there any trouble codes?
You did not mention anything about the Throttle Position Sensor. Was it tested?
Aug 14, 2012 at 6:17 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
The only code that came up indicated a bad Ignition module, which was changed (along with the coils). As for the throttle position sensor, I don't believe it was. Where is it located on the Corsica?
Aug 14, 2012 at 6:27 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
It is on the throttle body.
Aug 14, 2012 at 7:14 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Do you have any idea what I can try that I have not tried or changed?
Aug 14, 2012 at 7:17 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
First thing you need to do is to check what is missing when it stalled and could not start.

https://www.2carpros.com/articles/car-cranks-but-wont-start

The above link explains what to look for. Let me know what you find. Changing components without understand and checking if it is faulty is not the way to go about.

There are many possibilities and if it is elecrically related, that would make even more complicated.
Aug 15, 2012 at 11:48 AM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Thanks for the article and good advice. I agree, I don't have the
money to keep replacing components to see which fixes the problem.

I'm not sure how the article applies to my car. The car has no
problem cranking and starting up, even when it dies on me on the road.

After it gets warm, the car begins to stall when I try to accelerate
(usually on county roads). After it cools down, I've been able to
limp back home (slowly).

The real issues are:

1) Why does the car stall AFTER it warms up and in gear (Drive).

2) Why does it stall ONLY after I gas is applied to climb inclines.
Aug 15, 2012 at 4:01 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Stalling at operating temperature and easily cranks up can mean the idling speed is too low. When idling speed is too low, the IAC could be dirty resulting in inefficient air flow. Cleaning the IAC and throttle body should solve the idling issue as there are no trouble codes.

Aug 16, 2012 at 8:45 AM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Questions

What kind of cleaner should I use? Can I use something like WD-40?
I've seen several how-to videos on cleaning the IAC and throttle body.

Some have the engine running, others don't.

Which is correct?

Aug 16, 2012 at 7:52 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
You should get carb cleaner. WD-40 is not good enough. I would do it with engine off to get all the dirt out first. Spray into throttle and use a toothbrush to clear what ever dirt you can see around the throttle plate. Use a piece of rag to wipe off whatever you can and repeat a few times till the throttle is clean.

For IAC, spray and let it soak for a few minutes. Repeat sparying after waiting and wipe off.

After cleaning the first round, wait a while with thrpttle open and start engine. Might taking some cranking time or stall after starting due to presence of the carb cleaner. Once engine starts, flip throttle to prevent stalling and let idle stabilise.

If you are not satisfied and wish to repeat process with engine running, you may do so but you would have to flip the throttle to prevent stalling.
Aug 17, 2012 at 10:29 AM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
I notice the rubber hose that attaches to the throttle has a crack (see photo). Do I need to replace the hose? Where is the IAC located in the photo?
Aug 17, 2012 at 6:39 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS

IAC is on throttle body. In your first picture the one with 4 wires at left middle is it.

The cracked hose should be replaced as leaks would allow unfiltered air to get to engine.
Aug 17, 2012 at 7:04 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Thanks!

You wrote "After cleaning the first round, wait a while with thrpttle open and start engine. Might taking some cranking time or stall after starting due to presence of the carb cleaner. Once engine starts, flip throttle to prevent stalling and let idle stabilize."

Question - Can I test it without the crack hose attached?

Also, do I need to remove the IAC to clean it?
Aug 17, 2012 at 7:20 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
I believe your engine is not equipped with MAF so you can start engine without the hose. If equipped with MAF then it might not be possible as the MAF is connected to other end of hose at air cleaner and would result in stalling.

Removing the IAC would allow you to clean it better but you can try without first. Just make sure you spray into the air flow ports of the IAC inside the throttle body to get it clean.
Aug 18, 2012 at 7:44 AM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Throttle and IAC have been cleaned.

I started the car, waited for it to warm up and gave it some gas.
Once again it stalled, just like before.

The car cranks and starts but eventually stalls out.
...........................................

BTW - I did a simple check on the fuel pump.

1. I checked the fuse and relay - both were good.
2. With the gas cap removed, I listened for the pump to 'click on'
I could hear the fuel pump start (click).

Any thoughts on what to check next?

PS: I'm working on replacing the ripped hose.

Q - Do you know the proper name for this part?

Aug 18, 2012 at 4:38 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
That is the air hose for the throttle body.

Actually the idling speed can be adjusted and you might give it a try.

V6 IDLE SPEED
NOTE:
Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.

1. Install "Scan" tester to ALDL test connector located under driver's side of dash. Start and run engine to normal operating temperature. Observe Idle Air Control (IAC) minimum 10-20) counts.


2. If IAC counts are incorrect, use an awl to pierce cover of minimum idle stop screw. Apply leverage to remove cover. Turn idle stop screw out until screw clears linkage. Turn screw in until screw touches linkage. Turn screw in an additional 1 1/2 turns.

3. Turn idle stop screw in to decrease IAC counts. Turn screw out to increase IAC counts. If minimum idle speed correction requires more than 1/2 turn (in or out) of idle stop screw, check for vacuum leaks or dirty throttle plate. Clear any trouble codes.


Aug 18, 2012 at 4:52 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Thanks for the part name.

I'm a little hesitate to mess around with idle adjustments. I don't want to make things worse.

You need to know

1. I'm not a mechanic and the only reason I'm even attempting all
this is because I don't have the money for a proper mechanic.

2. I don't have a "scan" tester. Are they expensive?

Q - Should I try cleaning the throttle body and IAC again?

Thanks
Aug 18, 2012 at 5:15 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Yes, you can try cleaning the throttle again.

What is the idling speed after warming up?
Aug 18, 2012 at 5:22 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Where is the idle stop screw located (see photos).



Aug 18, 2012 at 5:29 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
How do I check the idle speed?
Aug 18, 2012 at 5:30 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
The one I have circled in red. You can try inserting a cardboard in between screw and stopper to test if it improves.

To check idle speed, note the position of the tachometer in dash.
Aug 18, 2012 at 5:45 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
I'll take a look at it. Is there any other way to test the IAC counts without using a 'scan' tester?
Aug 18, 2012 at 6:02 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
No, there is no other way but you need not worry about it for now.
Aug 18, 2012 at 6:12 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
What kind of test meter would you recommend?
Aug 18, 2012 at 7:05 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
You need one that is compatible with your vehicle and are rather pricey for those that can be used to perform the task required so I would say it is not really feasible unless you want to go full time into being a mechanic.
Aug 18, 2012 at 7:10 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
I cleaned the throttle body and IAC again. I started the car,
left it in Park, and ran it for about 15 minutes, while gradually
giving it more gas.

It stalled again, same as before. Once warmed up it will crank and
start, but it will not stay on.

Q - How do I check idle speed and position of the tachometer?
What exactly am I looking for?

I have very limited knowledge in car mechanics, so I need details.

Thank you.
Aug 20, 2012 at 5:33 AM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Tachometer is the gauge in dash showing 1, 2, 3, 4 and has the word rpm on it, next to speedometer.

It should be 3/4 between 0 and 1.
Aug 20, 2012 at 7:36 AM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
What did you mean by:

"Observe Idle Air Control (IAC) minimum 10-20) counts."

Q - The is the significance of a 'count' and what does it tell me?

"You can try inserting a cardboard in between screw and stopper to test if it improves."

Q - What will the cardboard do and how thick does it need to be?

"On the tachometer, it should be 3/4 between 0 and 1."

Q - What if it's too high or too low; what does it mean?

Q - What is the normal range for the idle on the Chevy Corsica?

Thanks
Aug 20, 2012 at 3:17 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
The count is for the scan tool. If the number is out of specs, the idling would be either too high or too low.

Any thickness of cardboard would do. Tht is for opening the throttle, as if you had adjusted the screw.

If it is lower than 700 rpm the engine might stall. If it is high, you would have higher fuel consumption and trmight jerk hard when shifting from P or N to R or D.

Most vehicles have idling between 700 to 800 rpm when idling at operating temperature.
Aug 20, 2012 at 3:52 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
https://www.2carpros.com/section/how-does-it-work

Check the link for more information.
Aug 20, 2012 at 3:56 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
I tried the cardboard and ran the car for a 1/2 hour, while gently
accelerating the engine.

The tachometer (RPM x 1000) never dropped or climbed past 1 (1000).

The car eventually stalled after I removed the cardboard. It seems to be having trouble recovering after more gas is applied.

Does this make sense to you?

Q - What kind of tool is needed to make idle adjustments?





Aug 20, 2012 at 6:17 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
That indicates the idling is possibly too low.

What you need to do is to extend the screw out slightly. The cardboard is to act as if the screw is extended.

A screw driver would be sufficient but at rear of the adjusting position, I see there ia a valve that is restricting you from adjusting. You would need to remove that first.
Aug 20, 2012 at 6:35 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
From another web site I read:

'You shouldn't have to adjust the screw; it's pre-set at the factory.
The computer controls the idle speed, that's why the idle screw is
sealed.

Is that true?
Aug 20, 2012 at 7:05 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Yes, that is true. under norml circumstances you need not adjust it but you are having a problem now.
Linkages and wearof related parts can cause the air flow to go uot of specs. That is the reason the scan tool calibration is required.

If you don't want to try adjusting, then you would have to replace it.
Aug 20, 2012 at 7:27 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
I was working on the car while it on and I notice 2 things

1. The coolant fan was not turning on
2. The temp gauge was climbing past normal levels.

There is plenty of coolant and there are no leaks I can see.

Any thoughts?
Aug 21, 2012 at 4:04 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
If the fans do not turn on when they are supposed to, it means a fault with the cooling fan control system. Does turning the A/C on makes any difference?
Aug 21, 2012 at 4:19 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
My A/C does not work; never has since I got the car.
Aug 21, 2012 at 4:20 PM
Avatar
KHLOW2008
  • CERTIFIED EXPERT
  • 41,814 POSTS
Here is the cooling fan schematic. What you need to do is to test if the fan motor is working. Locate the fan relay, unplug it and test terminal for battery voltage. If battery voltage is available, use a fused jumper wire to bridge it with terminal E. If fan turns on, the motor is good and so is the Fusible link.
Aug 21, 2012 at 5:54 PM
Avatar
RMONET2012
  • MEMBER
  • 46 POSTS
Fan is OK. Another thing I notice - the car stalls when I give it gas even when it's cold.

Any thoughts?
Aug 30, 2012 at 6:13 PM