February 8, 200620 yr When slowing down in gear, for some reason the engine surges as it goes between 1500-1400ish rpm. Feels like the throttle is being opened slightly, but its not! Seems to do it fairly consistantly. No ecs light. Idle switch is adjusted correctly. Any ideas? Maybe a sticky VAF sensor?
February 8, 200620 yr Im going on my experience with fuel injection from my IROC camaro seeing as how ive never owned a fuel injected suby. It "could" be the IAC (idle air control) valve. When mine was messed up it caused my camaro to surge coming to a light.
February 8, 200620 yr When slowing down in gear, for some reason the engine surges as it goes between 1500-1400ish rpm. Feels like the throttle is being opened slightly, but its not! Seems to do it fairly consistantly. No ecs light. Idle switch is adjusted correctly. Any ideas? Maybe a sticky VAF sensor? I would play w/the dashpot adjustment.It slows throttle closure after all.
February 8, 200620 yr Author I would play w/the dashpot adjustment.It slows throttle closure after all. Yes, but this happens even after decelerating from say 3500 rpm at closed throttle - feels totally normal except for a half second long surge as it goes through 1500rpm, then its fine again. I'll check it out though. IAC valves can certainly cause strange problems on some cars, but the valve on the ea81t is a simple temperature controlled unit, and i don't think it could open/close quickly enough to cause this problem.
February 8, 200620 yr I would check the throttle cable for fraying. I remember that after I reinstalled my engine I also had to replace the throttle cable. If it has to make any tight bends it can wear out.
February 9, 200620 yr Author Hmm, just noticed another oddity - if its idling, and i pump the brake pedal, the engine will speed up by about 200rpm for a second or so.......If i hold the brake pedal down, the idle doesn't seem to change though. Leaking booster or something??
February 9, 200620 yr Hmm, just noticed another oddity - if its idling, and i pump the brake pedal, the engine will speed up by about 200rpm for a second or so.......If i hold the brake pedal down, the idle doesn't seem to change though. Leaking booster or something?? Every time you pump the pedal you are emptying the booster vacuum chamber into the manifold.This is unmetered air.Since RPMs increase you must be a liitle rich.Monitoring the O2 sensor output voltage could prove entertaining.
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