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ASEMaster35yrs, Chevy Technician
Category: Chevy
Satisfied Customers: 2095
Experience:  ASE Certified since 1972,Master Auto tech,Heavy Truck Tech ,chev dealer tech
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1998 K1500 Vortec 5.7..running rough..Cranked

Customer Question

1998 K1500 Vortec 5.7 started missing and running rough out in a snow storm then quit. Cranked on it until battery was dead and then towed back to shop. Got it in next to the stove and started working on it. With charger on it, it would act like it wanted to start and then bang hard against starter like out of time. This only lasted a couple of times before starter was broke. New starter, good 68lbs fuel pressure, good spark on tester and at plug, replaced cap and rotor, crank sensor, cam sensor, power at all injectors, injector pulse at cranking all with the same result. Spraying carb spray, propane and even gas down the intake creates no effect. Swapped out coils with all the same results. On third starter now and it will backfire out the intake. I give up, I need some help
Submitted: 7 years ago.
Category: Chevy
Expert:  ASEMaster35yrs replied 7 years ago.
The first thing I would check is your compression. Your timing chain may have jumped time. If you are getting spark and fuel pressure and pulse, the only thing left is timing and compression.

Edited by ASEMaster35yrs on 12/27/2009 at 12:47 AM EST
Customer: replied 7 years ago.

Crate GM engine this February, did not check those because of low mileage.

Expert:  ASEMaster35yrs replied 7 years ago.
With all the things you replaced, getting spark and fuel pressure, it should run unless out of time or bad compression. If backfiring out of intake, there is an intake valve open when spark occurs.

Edited by ASEMaster35yrs on 12/27/2009 at 12:58 AM EST