Idle issue

L

Lirian

Guest
I run a 1989 t-bird SC 3.8L and recently had the motor replaced, prior to the motor problem the car ran without problems. Now with this new motor installed the car refuses to idle at correct RPM.

After various attempted to solve this problem, i unplugged the Idle Air Control sensor and the car idles and acts as though it should, although you can tell from the exhaust that it's running extremely rich. I've run the scanner on this numberous times constantly coming up with canister purge error when IAC is unplugged, when the car is on the scanner with IAC and idling rough, in addition to the canister purge code i receive various code indicating fuel delivery problems. Please someone give me a direction to go. thanks for your help
 
more than likely you have some vacuum leaks some where. With the IAC disconnected, the engine should barely idle. If it idles fine with the IAC disconnected then someone has adjusted the throttle stop to hold the throttle plate open to compensate for improperly sealed surfaces.

Somewhere air is getting into the engine without having to pass through the Mass Air Sensor.

Intercooler tubes are common places for leaks. Also the lower intake manifold plenum which bolts to the intake manifold behind the blower, or the top on the supercharger.
 
Hmmm, is there a way to get a picture of where the vaccum lines are supposed to be via the rear of the SC. I'm thinking it's possible they've been installed incorrectly.
 
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