R32 Rb20 Cold Running Issues.

[Truffles]

Seems to be a common problem with Rb20dets these days.

Upon cold starts my R32 the idle is rough and tends to hunt and drop after the throttle is released. The second problem is the car tends to jerk under partial throttle, almost like a surge. Upon WOT the problem isn't apparent.

Both these problems are only whilst the car is cold. They disappear as soon as running temp is reached.

I've gone down all the usual avenues. The BOV wasn't plumbed back and I did it a while ago. Cleaned AAC valve, reset ecu, changed plugs, swaped coilpack looms, changed coilpacks, cleaned AFM.

Could it be a throttle sensor problem with the second issue? If anyone has any insight it would be highly appreciated.

Edited February 26, 2013 by Truffles

[Kane_R32]

Does the "hunting" go away once you tap the throttle, on cold start up? Or does the engine come good after 10-15 seconds?

What mods?

[Dose Pipe Sutututu]

Is your AAC (aux. air control) working? I've found out with several RB20s in the past people tend to block them off completely because the AAC has failed causing high idle.

AAC is not the IAV.. this is located underneath the plenum and has a hose that connects to the crossover pipe next to the BOV... these things usually get clogged up with dust from using pod filters ra ra ra and seize up. Their purpose is to feed air post throttle body by collecting air pre throttle body.

Commonly cold start issues are due to AACs not working.