N'Syncro

2005 2.7T 6MT stg3+ allroad. Low miles, usually runs like a top.

Last weekend I drove it through a blizzard on the highway. As soon as I passed a couple cars, I noticed it go into limp mode (slightly at first, then it got much worse). Turned around and went home.


Here were my codes when i got home:
-------------------------------------------------------------------------------
Address 01: Engine Labels: 078-907-551-AZA.lbl
Part No: 4Z7 907 551 T
Component: 2.7L V6/5VT G 0010
Coding: 07715
Shop #: WSC 78901
VCID: 54AD026E8E7D
XXXXXXXXXXXXXXXXX XXXXXXXXXXXXXX

5 Faults Found:
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-10 - - - Intermittent
17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 35-10 - - - Intermittent
16556 - Fuel Trim; Bank 1: System Too Rich
P0172 - 35-00 - -
16559 - Fuel Trim; Bank 2: System Too Rich
P0175 - 35-00 - -
16485 - Mass Air Flow Sensor (G70): Implausible Signal
P0101 - 35-00 - -
Readiness: 0010 1101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4Z7 907 389 A
Component: ABS/ESP allrad D66
Coding: 06495
Shop #: WSC 02334
VCID: 4A911C165C39

2 Faults Found:
18265 - Load Signal: Error Message from ECU
P1857 - 35-00 - -
01422 - Hydraulic Pump for Electronic Stability Program (V156)
35-10 - - - Intermittent

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: Redir Fail!
Part No: 4B0 820 043 AR
Component: A6-Klimavollautomat 0208
Coding: 00010
Shop #: WSC 02335
VCID: 6AD1BC963CF9

No fault code found.



Took my MAF out, cleaned it, and that fixed the major limp mode problems, but then a couple days later my esp / abs lights came on temporarily and I had these codes:
18256 - Please check DTC Memory of Engine Controller
P1848 - 35-10 - - - Intermittent
18265 - Load Signal: Error Message from ECU
P1857 - 35-10 - - - Intermittent

Cleared the codes on Monday and everything seems to be good. I took it for a quick rip. I'm boosting about 20psi peak and leveling out at 17psi, I have good vacuum on the boost gauge. Car seems to be back to running like normal again, except...

I've been able to smell gas. It's insanely cold here right now (-20F), and I discovered today on my way to work as soon as the coolant temp reached normal opp temperature, it started to blow cold air out the vents, even though the interior was still pretty cold and my temps were set to MAX / HI. Shouldn't it pump way more heat than that? I've kind of noticed this before and it's always bothered me. It's COLD OUT! Blow hot air please!! It would only do that at idle though. If I was driving, it would blow warm air again. And as soon as I first noticed the cold air while idling was the moment I smelt gas. Once I started driving again, no more gas smell and no more cold air. And it didn't smell like gas at start up. Only after it reached normal op. temperature and then I sat idling for a bit. It's seen cold weather like this before and never smelt gas before. WTF?

I don't know if my MAF is still a bit faulty, or I messed around too much w/ the accordian hose and the bung coming out of it is not sealed properly, or I have a vacuum leak somewhere else or what? I suspect my wheel sensors are filthy and I need to clean them (tips, pointers?), but I know that's not the problem here.

Any thoughts or suggestions?

thejulex

You maf is shot. The following codes:
18265 - Load Signal: Error Message from ECU

show only when MAF is not workign at all and ECU siwtches to "MAFless" operation and uses pre-calculated flow tables for a given throttle angle values.

The side effect is that ECU doesn't know true load anymore and stops sending this to ABS subsystem.

ABS/EPL consequently throws an error since it cannot operate properly anymore.

It sounds like you need a new MAF unless there is some electrical issues there. Replacing just MAF sensor is the way to go since seeing that you're Stage 3+ you already have some custom MAF housing.

N'Syncro

I suspect me cleaning the MAF was/is only a temporary fix to a failing MAF, but how does that explain the gas smell?.... Which, by the way hasn't come back. Day 3 and it's still running perfect and I checked for codes last night and there was nothing.

N'Syncro

Engine light came on again today while running errands downtown today. Didn't affect driveability at all.

4 Faults Found:
17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 35-10 - - - Intermittent
16559 - Fuel Trim; Bank 2: System Too Rich
P0175 - 35-00 - -
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 35-10 - - - Intermittent
16556 - Fuel Trim; Bank 1: System Too Rich
P0172 - 35-00 - -
Readiness: 0000 0100


And after I cleared them, I logged some readings.

MAF topped out at 318.53 g/s which I read can be the upper limit to the stock Hitachi unit (which I have). That would mean my MAF is working properly, no?

fjasper

Gas smell in the cold can be leaking fuel injectors. They leak from the body of the injector. Won't do it when they warm up, has to do with different rates of thermal expansion of the materials making up the injector. New/rebuilt injectors is the fix.

Won't throw a code.

fjasper

Bump.

Did you figure it out/get it fixed?

N'Syncro

Nope.

It's been super warm here (around freezing), so I haven't smelt any gas. I read on some semi-local forums that guys have experienced the same smell when it's mega-cold, so i'm attributing that, or the leaky injector to the smell.

And I haven't driven it much lately, but I haven't tripped any codes. I'm thinking of just buying a new MAF sensor and installing it, and keeping my old one as a spare in the car just in case it ever happens again. Just trying to find the cheapest place for a new hitachi 06C 133 471A MAF. Cheapest i've found so far is $150ish at ECS.

To serve my own curiousity, anyone know what the stock size diameter hitachi MAF housing is? And airbox? Are they both around 83mm?

allroaddave

One other thing to check for the gas leak, the fuel tank has two vent lines one on either side that attach with a plastic fitting to the plastic tank, sometimes they break.....

N'Syncro

Thanks Dave. I'm going to have the AR on a lift tomorrow at a friends shop, so I'll have a look around the tank.

finiki

FWIW, I have the same gasoline odor issue when the temps' drop below zero(F).
Like your location it happens often in a Minnesota winter.
It is never an issue otherwise. The local Audi gurus attribute it to the fuel injector issue that fjasper mentioned. Maybe it blow up some cold morning and life will be less complicated ;-)