glidar

I've had my 2001 AR 6-speed for two months, with this behavior the whole time. When cold (and by that I mean the engine just hasn't been run in a few hours, whether the ambient temp is 10F or 60F), the engine doesn't run smoothly between 2000RPM and 3000RPM, especially under light-to-moderate acceleration. It runs smoother with the throttle more open or more closed, so I tend to try to accelerate briskly to speed then cruise lightly to let the engine warm up. After it's warm, it's fine.

I've replaced the 710Js with 710Ns - I wouldn't have expected any change unless the 710Js had been defective. No change.

The dealer said to try 87 octane in the winter at this elevation (5000'). After several tanks each of 87 and 91, I don't see a difference in the rough-running behavior.

Any ideas? I haven't touched the N75 valve yet -- don't know enough about its failure modes. No other mods. I've got a VAG-COM - no codes are shown.

BG AR

Not good for the turbos. You're better off driving slower until the oil temp. reaches around 175F before attempting any brisk accelerations. Rough running when cold is something not uncommon with the allroad, patience is the key.

ar2002

Or, your combustion chambers are carboned-up. Try a couple of cans of Techron or a can of BG44K cleaner.

glidar

but the tradeoff between the roughness and using a bit more boost isn't obvious to me. We're talking a relative increase in boost -- I'm not flooring it. But I agree - all things being equal, it would be better to take be gentle when the engine is cold.

paulroad

if so.. the dealer should be able to solve this. I think...that a proper diagnosis via their vag system will find the cause. IMHO...its tempurature related (coolant,oil,exhaust gas, etc.) Something is not sending the right signal to the given control units J valves, diverters, fuel injection, timing, etc. all receive signals from the ecu based on the temp. being sent from the other systems. Just my .02...

skidmark

problem on my car. don't know if other chips do or if dealer reflashed and fixed early stock programs to fix problem. jbo and i both had that stumble when cold. oct chip didn't fix it but apr chip did. that's my story

glidar

That's all I need -- less budget discipline! I've been planning to chip, but not for awhile yet.

Belmont

Reposting from Aug 2002:
I had the same concern until I found this previous posting:

"Re: warm up problems-sputtering and nearly stalling
Posted by JC-allroad on 2001-09-26 16:40:01
In Reply to: warm up problems-sputtering and nearly stalling posted by TTroy and jen in CO on 2001-09-26 09:24:09

The sound or sputtering is from the: Secondary air injection system (AIR) in short. The system uses an air pump to inject fresh air behind the exhaust valves for approximately 100 seconds during OUR cold start.

And after each subsequent engine start (up to 96C or 205F)the system will, switch in for 10 Sec during idle and is then monitored by itself, with a 20 sec delay.

What it's for?? Reduce exhaust emissions during engine warm-up and save our catalyst.

So, enjoy. And don't worry.. It's made that way.."

glidar

Not that I've timed it, but I don't think it lasts over 100 sec