[A4] RE: Mixture Too Lean P0171 Error

Yee, Phil Phil.Yee at rainin.com
Thu Mar 10 22:04:18 EST 2005

Update: shortly after writing the following thread, the error started to
cause a problem where I could not get beyond 5psi of boost.  Bad BPV?  More
vacuum leaks?  Check and swap and check and swap and check and nothing.  I
finally decided to pull out the APR chip.  Solder back the stock chip.  I
was a little nervous, but everything worked fine.

No more 5psi limit (back to approx 8psi/170hp), no error P0171, no 5k rpm
pinging, no signs of lean nor pinging whatsoever, smooth as butter (just a
little smaller stick of butter than before).  That chip was the source of so
much headache.  Before I de-chipped my car, I called the local APR dealer
for some support.  "Surprisingly" they no longer carried APR due to APR's
poor product delivery, product support, and mounting complaints.  Months
before when I called APR directly, they were all like "we test it, and there
should be no pinging.  have a nice drive."  IMO, it was amazing at the
beginging, but that APR chip ended up as crap.  Next time, maybe I'll get a
Giac, or an S4.

>-----Original Message-----
>From: Yee, Phil 
>Sent: Monday, March 07, 2005 12:52 PM
>To: 'a4 at audifans.com'
>Subject: Mixture Too Lean P0171 Error
>I've been getting the P0171 code a few times a week for about a month now,
along with a some >amount of pinging.  I've checked my fuel pump power
(fuses, relay), injector piezo 
>resistance measurement (per Bentley manual), vacuum leaks, and I still get
the message here >and there.  I did find a frayed and cracked vacuum hose
that goes from the intake manifold 
>to the BPV line, replaced it, and it really improved things (which
eliminated almost all of >the pinging).  I'm running an APR chip with a
1-cooler range NGK plugs.  The fuel filter is >only a few thousand miles
old.  The plugs are also a few thousand miles old, don't look bad, >if a
tiny bit on the hot side.
>It drives very well 99% of the time.  I get the error when I'm barely have
my foot on the 
>gas at about 1700-2500 rpm (very light load).  The only time I notice a
truly apparent 
>problem is when it pings sometimes under very high load in the 5000+ rpm
>Does anyone have any insights, or suggestions on what to check next?  (I
don't have a vag
>com, btw.)
>00' 1.8TQ
>01' 1.8TAvant

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