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Old 01-06-2011, 03:25 AM
  #4  
TopspeedLowet
Senior Member
DYNO OPERATOR
 
Join Date: Apr 2008
Posts: 504
Default If it runs ok when it is hot then

Lean mixtures burn longer than rich mixtures. You are likely very lean no matter which type of fuel system you have. What is causing this problem? Several things could cause this but the problem is likely a lean condition. Lean mixtures can still be burning from the previous power stroke and flash off the incoming intake charge when the intake valve first opens to fill the cylinder on the following intake stroke. Rich mixtures run out of oxygen and finish burning in the exhaust often in the form of a backfire when oxygen gets to the unburned fuel. A bad regulator or a too small injector or partially plugged injector, low fuel pressure, etc, etc.
Bruce
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