09-12-2019, 09:10 PM
MOST IAC fail stuck open hot, 180F and stuck wide open and RPM is like 2000 RPM hot or MORE, this is the classic failure. but not always,. they can stick closed.
or be (hacked)
hacking to stop the 2500 RPM hot racing, of RPM. idle. like putting in a solid paper gasket there , blocking all air flow.
the IAC can be tested in pan of hot water, but most times the screws are stuck and do not want to come off.
the other way is to blow in the hole marked INPUT port, engine off, and blow into that hole with rubber hose, jammed over that port by hand and lips on other end checking , yes I can blow air. (into the plenum)
and the photo above, we can block the port hot with clay to see if hot idle at 2500 rpm drops to 800. (the classic failure is this) we block it hot running engine using clay or electrical mastic putty. the put the air tube back or MAF is dead.
but this is not your problem racing, it is a dead IAC.
first off all , I am talking idle speeds hot and cold and on perfectly running engine.
and the engine with spark timing all wrong can not have idle working right,
Idle controls only work if all else is working right. (cam belt not slipped, compression at spec, spark timing set right) injectors not super lean or rich, ECU in closed loop hot.
IDLE is dead last of the things that can work right
but it sure can hide minor things wrong, it adjusts for cold weather and cold tight engine and a hot day. (or and old tired engine it will still work, but not compression at 100PSI (180 norm)
or be (hacked)
hacking to stop the 2500 RPM hot racing, of RPM. idle. like putting in a solid paper gasket there , blocking all air flow.
the IAC can be tested in pan of hot water, but most times the screws are stuck and do not want to come off.
the other way is to blow in the hole marked INPUT port, engine off, and blow into that hole with rubber hose, jammed over that port by hand and lips on other end checking , yes I can blow air. (into the plenum)
and the photo above, we can block the port hot with clay to see if hot idle at 2500 rpm drops to 800. (the classic failure is this) we block it hot running engine using clay or electrical mastic putty. the put the air tube back or MAF is dead.
but this is not your problem racing, it is a dead IAC.
first off all , I am talking idle speeds hot and cold and on perfectly running engine.
and the engine with spark timing all wrong can not have idle working right,
Idle controls only work if all else is working right. (cam belt not slipped, compression at spec, spark timing set right) injectors not super lean or rich, ECU in closed loop hot.
IDLE is dead last of the things that can work right
but it sure can hide minor things wrong, it adjusts for cold weather and cold tight engine and a hot day. (or and old tired engine it will still work, but not compression at 100PSI (180 norm)
http://www.fixkick.com