Fuel Injector Rehab

David Priebe davidpriebe at cablespeed.com
Tue Apr 20 00:39:02 EDT 2004

I just replaced this coolant sensor in my car a couple of weeks ago. I was
having fairly similar symptoms, hard start when warm (sometimes),  keep my
foot on the gas for 30-60 seconds, and then everything was fine. I would
also have hard start occasionally when cold. Again I'd give it some gas and
then it would drive fine. I assumed it was the check valve, and thought that
I would just deal with it until I replace my fuel pump (its gotten 'noisy').
But when I was having my chip upgraded, Alex at Intended Acceleration found
the problem, and quickly fixed it. So not only do I have much more
horsepower, but no start problem to boot!

Dave Priebe
Carnation, WA
91 200tqa 182k his
95.5 S6 114k hers
66 MGB 41k 

-----Original Message-----
From: 200q20v-bounces at audifans.com 
[mailto:200q20v-bounces at audifans.com] On Behalf Of Phil Rose
Sent: Monday, April 19, 2004 6:47 PM
To: Derek Pulvino
Cc: TooManyAudis at aol.com; 200q20v at audifans.com
Subject: RE: Fuel Injector Rehab

At 2:32 PM -0700 4/19/04, Derek Pulvino wrote:
>Without getting into the rest of the discussion (but it is a
>motronic system ;) ), I'll be curious to see what you find out Tom.
>I've got similar issues, doesn't start well when warm, and when I do
>get the car started when warm, I need to keep my foot on the gas, if 
>ever so slightly, to keep the car from stalling for about the first 
>3-5 minutes of startup (warm only!).  No problem on deceleration (ie 
>bypass valve), and it's not consistent at hot or cold engine temps. 
>This leads me to discount the idle stabilizer.  The other thing I've 
>noticed is it only happens when outside ambient is about 70-f and up.

I seem to recall that "poor running during warm-up" was stated (in 
Bentley) as  a symptom of a defective coolant temp sensor. The 
coolant temp sensor...is the one located on the backside of the head. 
Anyway, I think what happens is: if the ECU sees no proper input from 
the sensor, it then will use a temperature from the IM air-temp 
sensor to guess at the optimum fuel mixture during the first few 
minutes of running. See Scott M's write-up: 


Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net 
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