LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Doesn't start without pumping when cold

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Old Aug 17, 2009 | 12:19 AM
  #1  
castle70's Avatar
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Doesn't start without pumping when cold

Hi,
My almost bone stock(except cold air intake) 95' up until 2 weeks ago, would alway start right up without pumping the throttle when cold. I changed the
fuel filter, checked the plugs, air filter and today changed the Idle Air Control valve, which was definitely bad once my mechanic pulled it apart. No apparent vacuum leaks. But the problem persists....seems something has changed on it in the last couple weeks....any idea on this?

THanks!
Mike
Old Aug 17, 2009 | 12:32 AM
  #2  
MikeGyver's Avatar
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From: Orem, UT
Could be IAC related. Maybe pull it off and clean it out really well and ensure that it's working.
Old Aug 17, 2009 | 05:21 AM
  #3  
Injuneer's Avatar
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From: Hell was full so they sent me to NJ
Check the fuel pressure for rapid loss of pressure after the pump's initial prime. That will extend cranking time.

"Pumping" the accel pedal does nothing, except let more air in. Maybe that's an indication the injectors are leaking and flodding the engine. Next time, before you turn the key, put the pedal on the floor and hold it there. That puts the PCM in "clear flood" mode. If it starts faster with the pedal on the floor, it will tell you if flooding is the problem.
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