Will not start without a prime

1997 CHEVROLET TRUCK
245,000 MILES • V8 • 4WD • AUTOMATIC
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TIMMMY K
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  • 1 POST
I have a 1997 Z-71 with a 5.7 throttle body. All original under the hood with 245,000 plus mileage. I used to be able to just tap the key and it would start. Now it has gotten to the point where I have to pour gas down the carburetor body to get it started in the morning. I can turn the ignition repeatedly and hear the pump run. Sometimes doing that will get it to start. If not, a half cap of gas will get it to start. It will then stumble for a few seconds then smooth out and be fine. It almost seems like the fuel line is draining back into the tank and needs the vacuum of the engine to pull it through the line. I replaced the filter, and this helped for about two days. Is there a valve in the pump or tank outlet itself that went bad?
Jan 13, 2009 at 7:52 PM
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MERLIN2021
  • CAR REPAIR CONTRIBUTOR
  • 17,250 POSTS
Check the fuel pressure, and the pressure regulator. Click on this link for testing help. https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Jan 13, 2009 at 7:57 PM
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SHAWNBIGE3
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Temperature sensor next to thermostat. When they go bad they tend to give false reading that engine is warm that makes for difficult starting when cold.
Aug 29, 2018 at 6:12 PM
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DANNY L
  • CAR REPAIR CONTRIBUTOR
  • 5,648 POSTS
Hello, I am Danny.

Yes, It sounds like the fuel pump is not working correctly. Have you tested the fuel pressure? Hope this helps and thanks for using 2CarPros .
Danny-

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Aug 30, 2018 at 12:44 AM
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