Re: Air Flow Potentiometer repositioned to fix idle problem

["Alexander van Gerbig" <Audi_80@email.msn.com>]

    Well I was a sucker a year and half ago and my mechanic claimed I needed
a new potentiometer, that means new airflow plate as well.  That was an
expensive bit for sure.  Afterwards there was no change in any of the idle
problems that are associated with potentiometer problems.  The new ISV I got
at the same time fixed the real problems.
    After getting the new potentiometer/airflow plate everything seemed good
except for the constant idle surge during deceleration at 1500rpm.  That
will never go away, but I do know that is associated with timing.  The
further I advance timing the less the engine surges at 1500rpm during
decell.  I am not sure why that is, but associated with that is when I have
the timing set to stock (6BTDC) and disconnect the ISV the engine surges
severely, BUT if I advance the timing past TDC the surging goes away.  I
know for a fact that when the ISV is not connected and the engine is running
there should NOT be any surging, although the idle should rest around
1300-1500rpm.  To top that whole deal off I do get the "2232" code on
occasion, and sometimes everyday in the morning.  This usually happens upon
the first decelleration surge at 1500rpm, I get the code "2232", and then
the idle behaves as if the ISV was disconnected.
    This is a problem that I have yet to even come close to solving in my
head or on paper.  I really don't want to play with the trim screw on the
new potentiometer, VERY sensitive, and I don't really have the proper
measuring equipment to do this perfectly.  The potentiometer sends a voltage
signal to the ECU telling the ECU where the airflow plate is.  I believe
that my potentiometer may be reading the position of my airflow plate
improperly.  The deceleration surging is caused by a jump in current to the
DPR after the negative current used for deceleration fuel cutoff.  The
switch over from negative to positive current happens a bit too early and
causes the engine surge.  Along with the timing controlled surging, the
"2232" code, and the deceleration surging all of which seem to point at the
potentiometer, or something else?

Thanks,

Alexander van Gerbig -- '88 Audi 80

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