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My truck cranks normally but won't start?

Tiny
OUTLAWSGHOST
  • MEMBER
  • 2001 CHEVROLET SILVERADO
  • 6.0L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
My truck cranks normally but won't start. It will on ether but shuts off. I've replaced fuel pump and filter, plugs wires, cam shaft sensor, and crank sensor. Good fuel pressure to fuel rails. Coils and injectors are good. It's got spark. Fuses and relays are all good. Also replaced battery. Alternator and starter are good. Nobody can seem to figure it out. Please help.
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Sunday, November 29th, 2020 AT 11:55 PM

8 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Did you verify power to the fuel pump while cranking and when you first turn the key to on?

I attached a diagram of the relay and the pump for you. You need to verify power to the relay first on pin 30.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-check-wiring

Then 85 gets power directly from the ECM.

The grey wire at the pump is what needs power.

Roy

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Monday, January 25th, 2021 AT 10:16 AM
Tiny
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  • 5 POSTS
Hi Roy, I had my neighbor check it out and the pump and relay are indeed getting power.
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
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I have also changed the MAF sensor when I replaced all the rest of those parts.
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
If the pump is getting power and not running, then you either have a bad pump or ground.

Did you verify no fuel pressure?

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
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Fuel injected is getting power and running. I checked the fuel pressure at fuel rails and each time it's between 50 and 60.
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, next you will need a noid lid light to attach to one injector and crank the engine. It should flash indicating the ECM is commanding the injector open to flow fuel.

You can rent one at a parts store for this test.

Roy
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
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Okay, I'll try that next. Thank you.
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Monday, January 25th, 2021 AT 10:16 AM
Tiny
ASEMASTER6371
  • MECHANIC
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You are welcome.

Roy
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Monday, January 25th, 2021 AT 10:16 AM

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