Losing prime?

Tiny
WANDAANDBUDDY
  • MEMBER
  • 2007 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Just rebuilt the motor with stage 2 cam and put it in truck. Finally cranked it. Truck keeps losing prime. Have to turn it over a couple times every time before it will crank. Why is it losing prime?
Wednesday, March 5th, 2025 AT 8:25 AM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,251 POSTS
So it sounds like the engine is losing fuel pressure? It is fuel injected still, correct? It sounds like you may have a weak fuel pump or a dirty throttle body if still FI. Did you clean it before installation? Also do you have any trouble codes? Please go over this guide and get back to me.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

I would try holding your foot on the throttle slightly when cranking to see if it helps. It could be the throttle body needs to learn still. It might work itself out. Please upload a short videos in your response of the problem so I can see.
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Wednesday, March 5th, 2025 AT 4:34 PM

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