Cranks but will not start

1975 CHEVROLET SILVERADO
284,000 MILES • 7.4L • V8 • 2WD • AUTOMATIC
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WESTON454CHEV
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Hi, i have the truck listed above crew cab dually with the 7.4 liter (454) engine. I have brand new distributor cap and rotor,(it's hei ) new spark plugs and wires, new coil, fuel filter fuel line. I am getting spark and fuel i can pour gas down carburetor and it will still not start either. The story on this is the truck was driving and running amazing all summer. And then the next morning i went out and it started but had no power at all and would shut off with too much gas pedal, so i parked it for a couple days tried again started but same thing. Tried again week later and wouldn't start. it has has been 6 months and will not start. maybe you guys could help me. Maybe motor is wore out and low compression, but maybe not because it had tons of power all summer and the day before. And then just all of a sudden.
Apr 13, 2020 at 6:14 AM
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ASEMASTER6371
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Good afternoon,

If it does not start with priming it, I would start with a compression test. If you have spark and fuel, that is the next test. You can rent a tester at a parts store.

https://www.2carpros.com/articles/how-to-test-engine-compression

If you have the original timing gears, the cam gear is made of fiber and is common for failing.



Roy
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Sep 3, 2020 at 3:14 AM
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WESTON454CHEV
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I was also just going to ask is it hard to look at the timing gears while the motor is still in the truck?
Sep 3, 2020 at 3:14 AM
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ASEMASTER6371
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Yes, it is. That is why I requested a compression test. If you have bad compression on all cylinders, that indicates a timing chain.

Roy
Sep 3, 2020 at 3:14 AM
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WESTON454CHEV
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  • 19 POSTS
Okay, i will go out and do compression test then and let you know.
Sep 3, 2020 at 3:14 AM
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WESTON454CHEV
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  • 19 POSTS
Hey, i was going to ask; i found a 1985 Chevrolet 350 engine for sale would it fit in place of my 1975 454?
Sep 3, 2020 at 3:14 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Yes, it would.

It would be a direct bolt in.

The only difference is exhaust system.

Roy
Sep 3, 2020 at 3:14 AM
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