Cleaned IAC, now stalls on every start.

[CRCinAU]

Hi all,

Originally (ie what caused me to clean the IAC) was that even taking your foot off the accelerator would stall the engine (fun at 80kph!). So I cleaned the IAC and now when it idles, it is very smooth.

I used the howto on this site:
https://forums.justcommodores.com.au/threads/vn-vr-iac-idle-air-control-how-clean.5313

I've posted pics of the 'dodge' I had to do as the blasted screw snapped off (which is apparently common).

So - now that I've put it all back together, I've noticed that every time I start the car (hot or cold), the engine stalls. If I give it a bit of a squirt on the accelerator while cranking, it jumps into life and idles fine. It runs fine, idles fine while stopped at intersections etc...

I've hooked up EFI Live to the car and can see the IAC steps changing when the engine is reved and going back to idle. The mixture is good according to the O2 sensor. I also reset the IAC and LTFC using EFI Live after cleaning both the throttle body and the IAC.

This leaves me at a bit of a loss. The only thing I can think is that the IAC is not opening up enough for the start? Any thoughts on this? Any signs to look for on EFI Live?

 

[GTP 85]

Have u reset the iac? rev it in neutral up to approx 3k and let the revs come down on its own. Usually it will stall first time. Do it again, and the iac steps should reset

 

[CRCinAU]

let the revs come down on its own

I haven't done that... What do you mean by let it come down on its own? If its in neutral, then holding the accelerator at 3000rpm will keep it at 3000rpm?

 

[James39]

I haven't done that... What do you mean by let it come down on its own? If its in neutral, then holding the accelerator at 3000rpm will keep it at 3000rpm?

Which means remove your foot from the pedal once you have reached 3000 RPM.

 

[CRCinAU]

Which means remove your foot from the pedal once you have reached 3000 RPM.

Righteo

I wasn't too sure if you started it and straight away held 3000rpm that the ECU would back it back down to idle until the throttle was reset and used again. I've driven the car normally for about 100km - but it still stalls on every start. I'll try holding it at 3000rpm for a little while on start and see what happens....

 

[NickVR]

What Gilbs said is right to reset it. Best to start again from scratch.

1 Disconnect the battery (about 10mins should do)
2 Reconnect when time has passed.
3 Start the car and instantly rev the car to 3k or around that doesn't need to be exact. (hold throttle down a bit when starting if you want)
4 Hold it there until you hear the car change the revs by itself.
5 Keep your foot steady until it's finished and the revs are maintained.
6 Release the accelerator
7 Then put your foot on the brake and put it into reverse. Let it learn the idle (a few seconds should do it)
8 Then with your foot still on the brake put it into drive. Let it learn the idle (a few seconds should do it)
9 Shift back into park.
10 Then put the A/C on. Let it learn the idle (a few seconds should do it)

This will complete the idle relearn procedure. Steps 7-10 can be done when you drive it next but I do it straight away because sometimes it won't learn during a drive.

 

[FXST01]

When installing the IAC valve, ensure that pintle is less than 28 mm from the body. (the screw in tabs)

 

[aussie4life]

What Gilbs said is right to reset it. Best to start again from scratch.

1 Disconnect the battery (about 10mins should do)
2 Reconnect when time has passed.
3 Start the car and instantly rev the car to 3k or around that doesn't need to be exact. (hold throttle down a bit when starting if you want)
4 Hold it there until you hear the car change the revs by itself.
5 Keep your foot steady until it's finished and the revs are maintained.
6 Release the accelerator
7 Then put your foot on the brake and put it into reverse. Let it learn the idle (a few seconds should do it)
8 Then with your foot still on the brake put it into drive. Let it learn the idle (a few seconds should do it)
9 Shift back into park.
10 Then put the A/C on. Let it learn the idle (a few seconds should do it)

This will complete the idle relearn procedure. Steps 7-10 can be done when you drive it next but I do it straight away because sometimes it won't learn during a drive.

Would this be the same for a 94 vr v6 series 2 acclaim?

 

[yxyx64]

Hi all,

..... The mixture is good according to the O2 sensor.......

not sure what you mean by good but o2 not used at idle in vr. o2 should show high voltage at idle.

maybe clean iac again if above ideas did not fix as all this love may have dislodged some junk near iac .........

 

[NickVR]

Would this be the same for a 94 vr v6 series 2 acclaim?

I was told so but never tried it on a V6. I do it every time my car get a flat battery because it won't idle otherwise. But mine is a V8.