Well this is a good brain teaser for the org. I have been dealing with this since I did my 00VI maybe more than a year ago. But lately I have been thinking about what the hell could be the problem. Here is the problem:

In the mornings i start the car, and idle is rough. a/f is somewhat o.k. but as soon as you try and rev it, it leans out to 16's or even off charts and car just bogs and basically wants to turn off (same symptom as bad MAF). ok now after the needle gets directly over the Cold car, the car idles perfectly normal as if nothing ever happend and revs perfect. So this is a cold start issue. ONLY happens when needle is below C.

I have no iacv, but it shouldn't be causing the problem (no one else has the problem i have), cant be vacuum leak otherwise it would be all the time. What exactly happens during cold start? im thinking maybe an EVAP or EGR problem?

NOTE: i think during cold start ecu runs at open loop, but i cant blame the open loop because my car runs at open loop 24/7 since i have o2's disconnected and im controlling the a/f (below 3k) using vafc2. the starting issue has done it with this setup, and has also done it with o2's being connected (not that it matters cuz o2's are not taken into consideration during cold start)

 

Thermostat to some extent?

Might be a failing ECTS.

 

hmm, wouldnt a bad thermostat give problems all the time and not just at cold start? its worth the effort to try another one though. but i dont kno if it could be that.

 

Once the car is warm a thermostat stuck open would run the same, if it were stuck closed then it would be a different story.

 

The fact that your car warms up properly in a timely manner eliminates the t-stat.

 

Where does it say that. I don't have insider info

 

I would blame the absence of the IACV. The fms isnt really clear to what the IACV and the EGR do during start up. You going lean sounds like a vac though.

-matt

 

EGR is only active during cruising and light acceleration. Cold start, idle, and WOT are conditions where it's not active.

 

No one else with IACV deleted has had my problem. alot ofcourse have starting issues, but my problem is the warm up issue. and if it was a vac problem, why does it go away as soon as the needle gets on the C line?

A vacum problem would be happening all the time.

 

mine broke 2 weeks ago during WOT at 170km/h with ULTRA clanking sounds comming from the EGR valve itself. Your telling that it doesn't work during WOT... Mine broke during WOT, I stopped on the side of the road to check it and CEL came on as I sat in my car to return home to fix it...anyway, all this crap is about to come out of my car to be replaced by my 00VI next week, got my rear bumper fixed...

 

It might have been stuck open. It happens. When the system is working properly there's no EGR at WOT.