re: hard starting

["POWELL"<jim.powell@xxxxxxx>]

     Rob,
     
     If an injector has leaked down into a cylinder, would it be 
     diagnoseable from smoke at initial start up until the extra 
     fuel/fouled plug cleared?
     
     
     Jim Powell
     '98 M3/4
     
     
     
     
     >> Out of the blue Monday morning my 1987 535is had trouble starting! 
     It has
     >> always fired within a second of turning the key, but this time it 
     took
     8-10
     >> seconds of cranking to get it started. After a short drive, I shut 
     it off
     to
     >> run into a store. Came out and it cranked up like old times.
     
     Jim Cash wrote:
     
     >You are probably correct in identifying the " 'cold start' valve ".
     >The symptoms you describe are "usually" associated with the "cold 
     start
     >system".
     
     More great stuff plundered from Rob>>>
     
     Jim is usually 100% correct, and his diagnosis is the most likely 
     problem... however, there's one other possibility.  The car may have a 
     leaky injector which causes the fuel pressure stored in the system to 
     drop.  The pressure needs to build up, the pump builds the pressure 
     only when on -therefore when cranking.
     One symptom that may accompany the bad injector, that's "weak"
     running for the first 10 seconds.  The car will suddenly "jump awake" 
     after that.  What is happening (thanks to Brett Anderson for the 
     explanation) is that the bad injector has temporarily fouled the plug 
     in that cylinder. After the 10 seconds of running, the plug burns 
     clean and the extra fuel pooled in the cylinder is flushed out... now 
     all 6 cylinders work.
     
     - - Rob Levinson
     '85 535i Turbo
     
     <<<<<

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