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Topic: Stalls at idle

in Forum: C4 Fuel, Emission Control, and Exhaust Systems


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Stalls at idle (1/3)
 9/3/15 3:46pm
Cbarison
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Eastchester, NY - USA

Vette(s):
1987 c4


Joined: 6/25/2014
Posts: 31

Hi All,

I need some help! I've done a lot of work on my '87 C4, new cam, ported out heads and intake manifold and plenum. Valve job on heads, new water pump, spark plugs and wires. I've take out all of the smog control including the EGR because there were new headers installed. Also replaced the fuel pump to 255 L pump.

Now the car starts and runs but when I let it drop down to idle, it stall every time! I've checked the fuel pump, its working fine. Does this have something to do with the smog control? I know I've got to get a new computer chip for the car, but I've gotta get it to the tuner without stalling 50 times!

Any ideas?
Cbarison


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Re: Stalls at idle (2/3)
 9/9/15 9:20pm
REDVETTE85
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NORTON, OH - USA

Vette(s):
1985 C4 red, 1985 C4 Black and dark gray


Joined: 7/9/2012
Posts: 111

throttle posistion sensor resistance check and adj.?
Re: Stalls at idle (3/3)
 9/9/15 11:07pm
396c4
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Joined: 12/7/2011
Posts: 219

With all that changed, how much vacuum at idle? (with a gauge or MAP reading) If you have a vacuum leak, it will stall, doesn't take much. You can fatten it up by removing the vacuum line from the pressure regulator ( and capping the line) it so doesn't compensate for manifold vacuum which might compensate for the extra air coming from the leak. Idle could be high. Old school leak search uses oxygen around potential leak areas like the intake gaskets to find a leak, will speed up if you find it. Propane works but you want to be careful with that.

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