Justin517

i just replaced the turbo, the car runs great, a little surging when at WOT, all connections are good, and i have 22-24 in/Hg at idle, so i dont think there are any vaccum leaks, but i have a CEL, and its #1136 (i think that was the #) but its fuel trim idle too rich, does the MAF effect the idle circuit? ill have to do the rubbing alchol trick n see what happens, if not i prob need a new MAF (i think ill ahve to upgrade b4 i chip anyway, cuz im a 97) either way, any other suggestions?

Allroady DungBeetle

Cleaning it may/should do the trick. It's easy anyway so why not?

RKA

Check the hose from the turbo to the cross pipe. The clamp might be a little loose, and you might be losing metered air, causing the rich condition. Check any other [post-turbo] clamps you disconnected in the process of replacing the turbo.

Audi2ptzero

at idle the motor would be sucking in air thru a leak anywhere after the maf causing a lean condition. At idle the only leak that would cause a rich condition would be one at the fpr vac line. This is usually the first vac line to crack. When this line leaks there is less vacuum to lower the fuel pressure causing the rich issue, then during boost the car will run leaner since there is less pressure added to the FPR.

Devious27t

bad maf will generally cause car to lean out at WOT. rough idle comes with the territory

RKA

I've never seen a broken BPV hose throw off the fuel mixture enough at idle to throw a rich code at idle. So off to the search engine I go...in the process of searching, I found this:

17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 35-10 - - - Intermittent

He's got an old file on his vag.com where they I believe they mixed up the lean and rich code descriptions. I bumped into this before when trying to debug a car. Anyway, I agree with you...check for a broken BPV vac line.

Audi2ptzero

the fpr one usually is the first to go since it is right on top of the motor and cracks very easy. I have seen this on alot of cars and even had the problem on a car that I was racing at the drags. The car went real rich at idle and off the line and then real lean when at wot and full boost. Block 032 will show the #'s to be way off, this block is also a good way to tell you where your issue is at. A leak between the maf and turbo will show the both idle/PT to be lean, if the leak is between the turbo/TB (usually a bpv that is leaking out or ripped TB boot for the S4) then the idle will go lean and the PT will go rich. A vac line leak will cause the car to idle funny and cause the 2 #'s to change a little.

RKA

where it's so easy to access information and troubleshoot as it is with our cars?

I don't use a my vag.com very often, but in a lot of ways, it's nice to know that I have it, and I can search for any info I need to yank numbers for 1001 sensors on this car, and make some sense of them. I'd feel hesitant to switch to another brand if I lost that "power".

Audi2ptzero

But then he also tunes the car right from his lap top too.