Fuel Injector Rehab

Derek Pulvino dbpulvino at hotmail.com
Tue Apr 20 14:06:21 EDT 2004


The problems not so much during warm up (ie from a cold start) but more from 
starting the car when it's warm (ie after driving for 1/2 hour plus).  
Problem presents itself when the car is warm, the ambient temp is also 
around 65-70 plus, and I come back to the car to start it up after about 
15-minutes.  In that instance the car won't idle for about 5-minutes, but 
hmm, that is about the time interval that the coolant temp sensor default 
condition runs for.

If I remember correctly, the coolant temp sensor is more utilized in the 
injection matrix to inform the system of cold startup and to enrich the 
mixture accordingly from cold start, at least that's what I remember from my 
VW days.  If that is the case, I wonder if it would even come into play 

Derek P

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

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