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Alex Rhys


Hi all, in my quest for a perfect base to improve, I believe my S4 has developed an over fuelling problem.

Ive noticed the CAT smelling a little "eggy" lately... So i did a log with the Torque app and noticed the "Fuel Trim Bank 1&2 Long Term" is at 0.8 at all temperatures and driving conditions. Am I right in thinking the car is on cold start to whole time?

I have new genuine lambdas and SID EGT boards.

Many thanks for any help!
Alex Rhys

Click to download file
Alex Rhys

Aha! Just added that log file, didnt think it would work but way hey!

.8 on long term isn't over-fuelling, closer to zero the better. If it was -20 then it's over fuelling. Run it for a good 20-30 miles without clearing codes then re check fuel trims

IAT's are very high?

I'd suggest you do some logging with VCDS as some of the values on that log dont really make any sense.
Alex Rhys

Thanks for the input guys, my VCDS at the moment does funny things when trying to log so ill have to order a new cable i think.

What i didnt notice was the high EGT readings, coupled with the eggy smell, im thinking just off that alone the CAT's could be blocked causing high EGT temps and then the car possibly over fueling to compensate?

Of course i may be massively off here but on the flip side I have been contemplating decats...

i dont see EGT's in your log, and the factory sensors are stupid and dont read any lower than something like 940c.
Alex Rhys

Ahhh i read IAT's as EGT 's lmao... sorry!
Alex Rhys

Just to nip this up, I failed to mention that I had been sat in the car at idle for around an hour and a half before realising I had the Bluetooth obd dongle in the car and decided to give logging a whirl Obviously the Bluetooth dongles aren't that great in comparison to genuine VAGCOM.

With regards to the eggy smell I was getting, that was a boost leak I had created whilst changing the cam belt! lol

Thank you for the help guys and sorry to mess you around! Forum Index -> Audi S4 & RS 4 (B5) quattro
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