Shep 1.8T

The A4 board has turned into a bunch of kids who have no idea how Motronic 7 works, and my post become useless, unaswered bandwith. I STFA and found that most of the usefull LTFT threads to be in the S4 board so I figured I would try my luck here.

Here is the current situation.. I cannot pass colorado emissions, running too rich.

Current setup is APR Stage 3
and I'm in metro denver at 5400 ft altitude

Posted in bold is my actual number of emissons. All figures are in g/mile.

HC limits 1.200 <b>1.9768</b>
CO limits 20.00 <b>35.8539</b>

The car is tricked pretty badly at this point into thinking I'm running lean, and is adding fuel like all hell.

Here is a snapshot of my # 3 spark plug, all the rest of them looked the same, so I am running quite rich in reality.
<img src="http://pictureposter.audiworld.com/48848/cylinder_3.jpg">

I've gone on a series of replacing stuff ( via troubleshooting), hoping to draw down the numbers closer to 0 so I can pass emissions. So far here is the list of stuff I have replaced:

Fuel Pressure regulator
all 4mm vacuum hose
other vacuum hose
front 02 sensor
MAF

none has really made a difference in my LTFT's at all. When I check my readiness the CAT is always listed as failing for some reason, everything else will pass, but not the cat.

I have a hunch that there is an airleak, post MAF, pre turbo that may be contributing to the problem, but I don't own an air compressor, so I am at the mercy of who wants a 6 pack of beer in exchange for letting me use thier compressor. And while it may be contributing a little bit, I am wondering how far that's really going to send me out of limits, like I am. I'm thinking it may be a sensor instead giving a poor reading, somewhere.

I figure in Denver of all places, I should be seeing negative numbers for LTFT, less air+ fuel = rich, so the ECU should pull fuel in theory..

I've also read several articles on the net, about bad or sticking injectors and that OBD II will adjust AFR based off one bad cylinder, given the condition of the spark plugs, I don't think that is the case, but I've yet to clean the injectors either, sick of throwing money at things without gaining any ground.

What's my modus operandi for attacking this thing now? Have any of of you S4 guys found any crazy sensor failures that caused problems like mine?

Is there any possibility in a turbo/cat exhaust leak causing the 02's to be totally faked out?

BLK01S4

have you ever messed with the adaption channels via lemmi?

BLK01S4

call APR! .. You aren't homebrew this isn't really your problem honestly.

PSmalls::AnalRetentiveNumbNut

How long has this been going on? In other words, it hasn't been this way ever since you started running APR S3 at high altitude has it?

You could try unplugging the ECU, letting it sit for a half hour or so, and then plugging it back in. I doubt it'll do much, but at least some things will reset.

Also FYI, you can watch short term fuel trims in block 001 of VAG-Com. If you do this, you may be able to get a better idea of what situation/circumstance causes the ECU to pull so much fuel. Then again, it sounds like the ECU is pulling lots of fuel all the time.

BLK01S4

or call APR

Shep 1.8T

no, I thought that was more of a DBW thing, I am still old school with my throttle cable

Shep 1.8T

and I'm learning a lot to say the least.

These ECU's are smart, and create thier own values for MAF/coolant temp sensor readings among others if the signal is dead or incorrectly calibrated. There is also a set function that shuts off other variables, either gives them an artificial value, or prevents thier functioning that allow the car to adapt over time. If adapatation is done incorrectly, then the car can actually have increased emissions, or rough idle, even though nothing is wrong.