Fluctuating Idle

[BurnBarfield]

Okay, I just bought a 93 Talon TSI AWD and we just got the head gasket fixed on it and all..

Well, when we get it back together, the idle will fluctuate, it will be around 1400, then drop to about 900. It will then go back to 1400 and repeat.. I don't remember if this happened before, as I avoided driving it all together.

Once the fans kick on, the idle is fine though...

Any ideas?>

BTW!! The BOV wasn't recirculated when I bought it, and I still don't have a hose to do so.. Could that be it?

 

[bojanglesracing]

Yea thats it get that hose.

 

[Weapon X]

i think i remember reading somewhere that the recirculated air is takin into acount by the computer, so unless you have a standalone system of somesort then you deffinetly need to get that tube..

 

[TurkF26]

i think i remember reading somewhere that the recirculated air is takin into acount by the computer, so unless you have a standalone system of somesort then you deffinetly need to get that tube..

Yes you are correct in the first part of your sentence but the second part is incorrect. TO "vent" your BOV, you do not need a standalone system but rather a GM MAF and Translator placed between the BOV and your throttle body. This way the air that is metered is after the Blow off Valve opens.


As for the original question, yes you need to recirculate the BOV but no, at idle that would not cause your idlesurge. This is most likely caused by a faulty ISC which controls your idle.

 

[Weapon X]

Yes you are correct in the first part of your sentence but the second part is incorrect. TO "vent" your BOV, you do not need a standalone system but rather a GM MAF and Translator placed between the BOV and your throttle body. This way the air that is metered is after the Blow off Valve opens.


As for the original question, yes you need to recirculate the BOV but no, at idle that would not cause your idlesurge. This is most likely caused by a faulty ISC which controls your idle.

good point i forgot about that, but cant it work either way? standalone or re-placing the MAF?

 

[TurkF26]

I am not to familiar with standalone units so i do not know if a standalone unit can do that or not. If you are at the point in a build that you need to use a standalone unit, im 99% sure that you are not using the stock MAF at all.

 

[Weapon X]

good info, anyways g'luck Burn..