DTCS 17535, 17537...long term fuel trim rich on my A4...

[Rob Andrews]

If anyone of you guys has ideas...I'd love to hear em...
Below are copies of email between myself and another Audi tech friend....


Ok ....here is the latest in my diagnostic.
Bank 1 and 2 still going to -25%
I looked at block 001 and 004 for coolant temp to see if that was going
crazy but the reading seemed fine.  There are no pinched fuel hoses that I
can see and I looked from the tank to the rail.  I pinched off the purge
valve and that made no difference.  Swapped FPR and MAF, cleaned thottle
body, changed plugs (which seemed to help for a little while...went to -21%
and then rich to -25% after a day)
What am I missing?  I'm about to jump from a cliff!

Pinched off the valve (tried both sides, but only 1 at a time) and it made
no difference.
I did just swap my plugs and I will drive the car tomorrow to see if that
helps. The old ones looked tired. I'll get undeneath to check for fuel hose
crimps tomorrow, and swap another MAF with an A6 that is known to be good to
see if it helps. I'll report back once I have these findings.
So far...
Still stumped :(

> -----Original Message-----
>
> Sent: Tuesday, December 31, 2002 4:52 AM
> To: rob at robsaudiworld.com
> Subject: Re: Hey Mike...
>
>
> Early 99 probably don,t have 211.
> The purge valve is on the right hand side of engine bay on
> top of air
> cleaner assembly.
>
> ----- Original Message -----
> From: "Rob Andrews" <randrews at sbcglobal.net>
> To:
> Sent: Monday, December 30, 2002 11:51 PM
> Subject: RE:
>
> > Thanks!
> > But where the heck if the fuel tank purge valve?
> > Measuring block 211? That seems pretty high. I have an
> early 99 model
> > (i.e. the first of 99s to make it over here)
> > The light only comes only when cruising. My fuel trim is
> -25 and -23.4%
> for
> > bank 1 and bank 2...pretty darn rich. It only takes a few
> minutes of
> > driving to get it that way as well.
> > o2 sensors seem to be fluctuating enough, from around .1 to
> almost .9
> volts
> > and the heaters look to be working.
> > I'm going to try one more MAF tomorrow in hopes that may
> cure it...but I
> > don't hold my breath...
> > I'll poke around bentley somewhere and play with the car tomorrow.
> > As always...your help is gratefully appreciated.
> >
> >
> > > -----Original Message-----
> > > From: mike hadley
> > > Sent: Monday, December 30, 2002 6:51 PM
> > > To: rob at robsaudiworld.com
> > > Subject: Re:
> > >
> > >
> > >
> > > ----- Original Message -----
> > > From: "Rob Andrews" <randrews at sbcglobal.net>
> > > To: "'
> > > Sent: Sunday, December 29, 2002 10:10 PM
> > > Subject: RE:
> > >
> > >
> > > >
> > > > Well I hate to bug you again, but I figured I could use
> > > your expertise.
> > > > My 99 A4 2.8Q is throwing DTCs 17535 and 17537...long term
> > > fuel trim rich
> > > > for bank 1 and bank 2.
> > > > I tested the MAF, and swapped with another friends,
> swapped the FPR,
> > > tested
> > > > the 02 sensors with Vag-com and meter and they seem to be
> > > within spec.
> > > > Any other ideas what could cause such a problem?
> > > >
> > > > Rob
> > > >
> > > I take it with a known good mass meter it still came on?
> > > I guess the 1rst thing would be to pinch of the fuel tank
> > > purge valve to
> > > make sure it is not sucking fuel vapors when it is not
> supposed to.
> > > make sure the fuel return hose did not get pinched
> under the car (
> > > sometimes damaged on lifts or jacks) which will raise
> fuel pressure.
> > > With the Vag com look at measureing block 211 in Engine.
> > > See if it shows
> > > Maf grams per seconds. There should be a specified and actual
> > > amount. Drive
> > > the car under load and watch numbers, they should stay
> > > close.( does not work
> > > on all 99 and earlier cars)
> > > Also does the light come on at idle or when cruising?
> > > Let me know.
> > > P.S. if it cures the problem when pinching off the purge
> > > valve it may be
> > > the valve or a saturated charcoal canister ( if you like to
> > > squeeze every
> > > bit of gas when filling.
> > >
> > >
> > >
----------------------------------------------------------------
Rob Andrews
99 A4 2.8QS   83 Ur-Q
www.robsaudiworld.com
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