quattro Digest, Vol 58, Issue 9

[David Michael]

 Gary,

It may or may not be relevant, but I chased a no-power/hesitation/lean
running condition on my 200qa for more than a year. I had checked and found
all of the control and static pressured in the FI system to be OK. I made
sure there were no vacuum leaks. I had a clean a air and fuel filter. I had
an occasion code for "no hall signal", but that "usually" is to be ignored
if the car actually starts.....

What it turned out to be was 80% bad hall effect sensor and 20% weak fuel
pump. The pump was delivering the bare minimum fuel, but would not do so at
pressure. (blauparts has them for very cheap - or at least did a few months
ago). But the big problem was the hall effect sensor was sending false
triggers. I finally figured that out by looking at the hall sensor output
with an o-scope as the car ran.  Had your car thrown any codes? (step 1).

Also, but I found that there are NO mechanics  around who are competent to
work on the CIS systems anymore.. So you may need to invest some time

Good luck,

Dave



>
>
> ---------- Forwarded message ----------
> From: b1biker at aol.com
> To: quattro at audifans.com
> Date: Wed, 06 Aug 2008 14:42:10 -0400
> Subject: Continuing Problems 88 5KSQ
> Fellow listers. driveability issues continue to plague me. A brief update
> on the current problem. About 10 days ago I installed a new power steering
> pump and multi-function temp sensor, when I returned the pump core to the
> parts store it ran fine; on my way home when I tried to accelerate it just
> fell on it's face and had to be shut off before it would run again. I
> checked the fuel pump, changed the air filter, and tried disconnecting the
> O2 sensor. With the sensor unplugged it ran marginally better mut not
> properly. I put the car into the shop on last Monday; ther found, and
> replaced?a defective?O2 sensor; now they tell me that it's running way lean
> and they're having trouble getting the allen screw loose so that they can
> adjust the mixture. they said that they suspected some sort of electrical
> problem due to the sudden on-set of the problem but everything seems to be
> working properly. They have checked for vacuum leaks and can't find any. Now
> they are going to adjust the mixture but are having problems getting the
> allen bolt loose so thaty can accomplish that task. This is a small
> independent shop that has a very good reputation, I've been very happy with
> their work in the past.
>
> I'm at a lose as to where to look. I don't understand how the mechanical
> adjustments to the MAF sould suddenly get out of whack. I've already spent
> more than the value of the car in repairs over the past 6 month; which
> really isn't a problem as I plan on driving it for quite some time. Any
> advice, hints, BTDT, solutions?will be greatly appreciated.
>
> Thanks in advance,
> Gary Meier
>
>
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