: 4100 stalling after intake gasket repair



sk187
03-29-12, 10:01 AM
I finished replacing the intake gasket on my grandmothers car a few weeks ago (86 Deville 4100). The car ran fine for me while test driving but she says it is stalling out as she slows down and is about to stop and while accelerating from the stop.

I did notice when I was watching it the motor idle there was some smoke coming from under the carb. It almost looks like one big thick gasket (yellow in picture) about a inch thick under the carb was leaking. Could a bad gasket be the cause of the stalling?

Is there a way to turn up the idle of the engine? I know there is a bolt (red in picture) that looks like it can be turned out to keep the idle higher.

Any information would be helpful, thanks.


http://i40.tinypic.com/24l50r4.jpg

drewsdeville
03-29-12, 10:35 AM
Could a bad gasket be the cause of the stalling?


Yes.



Is there a way to turn up the idle of the engine? I know there is a bolt (red in picture) that looks like it can be turned out to keep the idle higher.

No

sk187
03-29-12, 09:13 PM
Thanks for the reply, what does the bolt in red do?

dennis93coupe
03-29-12, 11:26 PM
Sounds like you have vacuum leaks. Check all of your vacuum hoses and lines, fix any and all cracked and or broken hoses gaskets etc. Yes that thing circled in red in your photo controls the idle, ISC (idle solenoid control) more to it than just turning out the screw. I don't think that's a carb, most likely a throttle body with fuel injectors up top.

sk187
03-30-12, 02:14 PM
Sounds like you have vacuum leaks. Check all of your vacuum hoses and lines, fix any and all cracked and or broken hoses gaskets etc. Yes that thing circled in red in your photo controls the idle, ISC (idle solenoid control) more to it than just turning out the screw. I don't think that's a carb, most likely a throttle body with fuel injectors up top.

Thanks I will check all the vacuum lines tomorrow.

Does anyone know what you would call that large gasket under the throttle body?

carnut
03-30-12, 08:02 PM
"under throttle body gasket" or throttle body base gasket. With the engine temp up to normal, raise the idle at the throttle body with one hand while pushing hard on that "red" screw with your other. The shaft will retract slowly. Then quickly remove its wiring connector. Then let the engine come back to idle. It will be about 500 RPM. Verify .060 gap between the red bolt and the throttle arm. Adjust the shaft as necc. to get this gap. Shut off engine. Reinstall the wiring connector and restart the car. It should idle around 650 in gear warm, A/C off.

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Make sure you quickly remove the wiring connector at the idle speed motor (ISC) If left retracted and powered, it will short that idle circuit in the ECM!

drewsdeville
04-01-12, 12:15 PM
FWIW, you shouldn't have to push "hard" on the ISC plunger. All you need to do is close the contacts on the "closed throttle switch" and the ISC will automatically retract. No force required. Those are only plastic gears inside...

carnut
04-01-12, 01:06 PM
I said hard because most folks will just press on it and think it will power in. The most important thing is to QUICKLY remove its electric connector so as to not damage the ECM