Strange idle issue

Back when i was turbo. i had some weird issues with idle, and the car not running correctly. i just found a video i took, which illustrates this problem.

at 4 seconds in, right at the begging right when i reach the car, you can notice he exhaust note changes from a smooth idle to a rough lumpy idle. there are points where i hold the car at a certain rpm in between revs, it is also noticeable here in the exhaust note. this is the problem i had, and this rough idle would make the car die. does anyone have a clue what it could be?

listen carefully, may help to turn the sound up a bit
http://video.google.com/videoplay?docid=4998178763152644740

 

Does it goe from smooth to lumpy right after startup? Or does it take a while? You have different enrichments that come and go, like cranking, coldstart, and warmup.

 

Injectors.

 

the car would, idle fine at start up but after idling for 10-15 minutes, would go all lumpy. it would come and go in cycles, i could keep the RPMs up around 2k and it wouldnt stall. then the lumpyness would go away, for another 10-15 minutes. ect....

i was truely stumped, and this is pretty much why i dont have the turbo on any more (cuase it would do this at stop lights, and it got worse over time)

 

clean your IAC valve

 

There is a post on nasioc bout this. Can't remember what causes it but pretty much all the guys turbo'n there RS's have the same problem. One fix I heard was one guy raised his idle bout 200 RPM. It would still get a lil lumpy but it wouldn't die anymore.

 

^ do you know anymore about this so called post?

erik: car runs perfect without the turbo on, i doubt the AIC got dirty and then suddenly cleaned up w/o turbo

 

bad leak with your iac? why doesnt mine do it?

 

The IAC is located right under the TB right? i wonder if i did have a horrendous leak there. do you have a diagram of where th thing is?

 

Its very common for the IAC valve to get dirty/gummy. I'd give it a try. In fact, I think mine might need it too.

 

i clean mine often, along with my MAF

 

actually come to think of it i actually spent a few hours and took the IAC off and cleaned it. the problem still persisted. again this only happened when i was turbo (almost a year ago) when i took the turbo off the issue went away.

 

it has to be somthing in that baron hose , however you had it setup

 

the baron hose is the one which connects from the intake to the IAC right?

 

correct sir

 

hmm....

 

Sooo...... If your not having the problem anymore..... Why are you trying to fix it.... If it's not even there....?


^I enjoy dots.

 

for when he goes turbo again!!!

 

I am just puzzled by it. this is the main reason i took the turbo off, and i NEVER figured out what was causing this to happen. i guess part of it is just curiosity, and the other is me wanting to boost again ;-)