Hard start, cold start problem, rough idle...now Idle Switch/MAF Code

[Derek Pulvino]

Isn't the speed sensor one that will also throw a fault code if it goes bad? 
  When people have had them fail, has that happened...ie get a speed sensor 
fault when that's attributed to running problems in the car?

Just got a quote from SJM for the idle switch...only available through Audi 
for the ever so reasonable sum of just under $400.

Anybody have an extra speed sensor they want to loan out for the sake of 
"science?"

Derek P

Message: 2
Date: Mon, 03 Jul 2006 13:34:42 -0400
From: Kneale Brownson <kneale at coslink.net>
Subject: Re: Hard start, cold start problem,rough idle...now Idle
	Switch/MAF code
To: "Kenneth Keith" <auditude at gmail.com>,200q20v at audifans.com
Message-ID: <4.1.20060703132350.01155998 at pop.powerc.net>
Content-Type: text/plain; charset="us-ascii"

The 5k and 200 sensors are the same and cost around $100 new.  The V8 has
two such sensors, same as the other two except for the color of the
insulation on the wiring (one's gray and the other's black), and the length
of the wires.  The V8 sensor price is in the $150 range and the one with
black insulation supposedly is no longer available.  I bought two for our
V8 #1 a couple years ago and put black tape on one to make identification
at the wiring connector easier.   I just got a new 5K/200 version for use
on our V8 #2, which has developed the non-restart when hot symptoms.  The
gray wire is three times as long, but I have enough black tape to make it
look black, and I bet I can find a way to take up the slack.


At 09:22 AM 7/3/2006 -0700, Kenneth Keith wrote:
>Kneale Brownson <kneale at coslink.net> wrote:
>>
>>Just for curiosity's sake:
>>
>>On the V8, the engine speed sensor has a history of failing with age.  It
>>sits under the driver side exhaust manifold, supposedly protected by a 
>>heat
>>shield.  When it starts to fail, the car will not restart when hot.  Will
>>start cold and run OK cold/hot, but shut it off and try to restart a few
>>minutes later and there is no go.  I'm guessing the ECU needs signal from
>>the sensor to let the ignition spark.
>>
>>Has anyone ever found an engine speed sensor go bad on an I-5 engine?
>>Could that device cause poor idling on an I-5, but not necessarily no 
>>start?
>
>Yes, my buddy's '89 200q10v had an RPM switch go bad, which would make
>the car die when hot.  We put another used one in and it is okay now.
>I had never heard of that failing until this incident, but another
>person pointed us in that direction claiming it's a common failure.
>Upon describing the symptoms, he went straight to that diagnosis.
>It's simple enough to check if you have another sensor to try.
>
>Cheers,
>
>Ken