help, car idles erratically after injector swap. i replaced the injectors with the same size that it had before. i have 16" of vacuum and tps is .54 volts with throttle closed. i disconnected a vacuum line at one point and the idle improved. it starts fine and revs fine. i can't hear a vacuum leak anywhere and there are no check engine lights. i'm stumped.


update, the erratic idle is only when it is cold. when it warms and goes into closed loop it idles fine.

 

anybody?

 

Those 30# injectors in your signature could be a problem.

 

An erratic idle or hunting idle is usually caused by a vacuum leak. I know you said you cant hear it, but I could not hear my last vacuum leak either. Get a propane tank and with the engine idling, move the tanks tip around to all of the joints (theres plenty on a TPI). If the idle picks up repeatably each time you check a specific place, then you have a vacuum leak.

Also, If you do not have a chip burned for 30#/hr injectors that can lead to problems. But, I will still say its a vacuun leak.

 

yeah, my chip is burned for the 30lb injectors.

it doesn't do it all the time.it will be surging, then just stop. it doesn't seem to matter if it is hot or cold. last night, i took off a vacuum line and it ran better. plugged vacuum line with my finger and it stalled. i also have between 16 and 19 inches of vacuum unless i'm giving it gas.

could my cold start injector have finally ask for a grave?