Still Rich - ideas???

Peter Schulz pcschulz at
Tue Jan 15 14:08:21 PST 2008


Put an oscilloscope  or VAGCOM on the O2 sensor and ensure that you 
don't have a "lazy " one...
make sure that the O2 sensor has a good ground path.

At 02:19 PM 1/15/2008 -0700, Brandon Rogers wrote:
>My exhaust, not my bank account that is.....
>So anyway still chasing a rich idle and or decel condition.  As a
>reminder, here's the situation:
>Car is a 1984 urquattro with 3B conversion.  It has been rich since the
>motor swap 4.5 yrs ago.  It passes Colorado's tough rolling road
>emissions so I think it runs fine under load - its idle and decel that I
>think are messed up.  While driving and I come to a stop with windows
>down, a very rich exhaust smell wafts into the cabin pretty much every
>time - it is strong enough to become a real annoyance - and I know
>something just ain't right.  The exhaust is just plain rich when idling
>- When I park, the air around the car is rich exhaust.  If I drive to
>the store (1 mile) with windows down by the time I get back my clothes
>smell - the wifey usually comments, "you drive the red car to the
>store?"  "Yep."
>So so far:
>- No Codes
>- swapped _back_ in the new 02 sensor I installed during the motor swap
>- I had swapped it out 3 years ago for the old one chasing the rich
>running.  No change either time.
>- swapped in a bone stock ECU - no change
>- swapped in 2 different MAFs - one a 3B one an RS2 - no change
>- replaced the temp sender in back of head - no change
>- replaced the FPR (2 yrs ago) - no change
>- pressure tested for boost leaks numerous times
>- had injectors serviced by RC Engineering
>- swapped in a known good TPS - no change
>- removed Idle Stabilizer and thoroughly sprayed with throttle body
>The one thing is that I should check is the wiring for the Temp Sender
>on the back of the head.  I don't think the MFTS has an effect but maybe
>I'm wrong.  MFTS was new at swap - and remember it's been rich the whole
>time.  At least I don't recall it ever not being rich....
>Can anybody think of anything else??????  This is driving me nuts.
>200q20v mailing list

-Peter Schulz
Chelmsford Ma, USA

1995.5 S6 Avant Emerald/Ecru
1995.5 S6 Avant Silver/Platinum
1991 200 20v Q Avant Titan Grey (for sale)
1991 90 20v Q Red
1991 CQ silver  (eS2 recipient) 

More information about the 200q20v mailing list