Re: problem with S2 92

[Sachelle Babbar <sbabbar@iris.nyit.edu>]

Do the 3B cars have the same (I think it's) 4,000 rpm cutoff if you have
your foot on the brake and gas at the same time? Cuts off only on boost,
right?



****************************************************************************
*Steve                                       Sachelle Babbar
*'84  5ksT 1.6-2.0 bar                    <SBABBAR@IRIS.NYIT.EDU>
*Cockpit adjustable wastegate, AudiSport badge
*
*Disclaimer:"Any information contained herein is based purely on my own
*personal experience and may not necessarily reflect yours. Use caution as
*your results may vary from mine."
********************************************************************************

On Wed, 29 Apr 1998, Robert Houk - SMCC WorkGroup Server Firmware wrote:

>    Having the engine shut itself down at 4000 RPM sounds typical of an Audi
>    engine that is sensing a potential problem and is allowing you to use it in
>    "limp home" mode.  Since you only see the problem under boost my thinking is
>    that either the engine is producing too much boost, or the sensor in the ECU
>    thinks that the engine is producing too much boost.  The typical service
>    diagnostic is to attach a separate boost gauge to the intake manifold and
>    observe the boost pressure under certain load conditions.  There is a boost
>    curve that is expected for your car ... perhaps you can get a copy of this
>    graph from a dealer, or someone who happens to have the graph for the S2 ...
> 
> If the engine shuts down only at *4000*, it's probably not overboost
> (which leaves only 99 other things!).
> 
> On some older beasts (the UrQ, fer instance), the intake manifold air temp
> sensor would exhibit this same symptom -- at 4000RPM if it is "out of
> range" the ECU will shut down the engine, but *only* if under boost...
> if you ease the engine to 5000RPM and then "boost" it, it runs right
> to redline with the faulty sensor.
> 
> I'm pretty sure (I certainly *HOPE*) Audi doesn't use that same <expletive
> deleted, but it's a past participle> air temp sensor, but they may well
> have kept the same algorithm. (As a quasi-non-random experiment, if you
> can easily access the ECU, unplug and replug it a coupla times [engine/
> ignition *off*, natch!] and see if this has any effect on the problem.)
> 
> 					-RDH
>