Will not stay running?

1994 GMC SONOMA
130,000 MILES • V6 • 2WD • AUTOMATIC
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ORTEGAEDDIE
  • MEMBER
  • 3 POSTS
I have the truck listed above that has complete engine rebuild, new MAP, new distributor, new ignition switch, all new sensors, new fuel pump, new fuel filter. basically I have replaced everything on this truck and I cannot get it to stay idling. it starts beautiful and idles for about one minute and shuts off and each time i start it, it will stay on less. i have checked for codes and it is not throwing any codes. I am at a loss, don't know what else to check. Any help would be greatly appreciated.
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Jul 3, 2021 at 3:53 PM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
Good morning,

I would start by testing the fuel pressure. Make sure it is within specs. I post the specs below for you. You can rent a tester at a parts store.

https://www.2carpros.com/articles/stall-at-idle

For the CPI or central system

Fuel Pressure Specification:

With the ignition ON & fuel pump running .................... 380 - 420 kPa (55 - 61 psi)

For the system that has a throttle body

Fuel Pressure Specification:

Ignition ON & fuel pump running .................... 62 - 90 kPa (9 - 13 psi)

It does sound like the fuel pump is the issue but needs to be confirmed.

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

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Roy
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Jul 3, 2021 at 7:14 PM
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ORTEGAEDDIE
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Thank you so much. We did test that first. Fuel pressure is good. Any other ideas?
Jul 4, 2021 at 9:14 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
What is the pressure?

Roy
Jul 4, 2021 at 10:38 AM
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ORTEGAEDDIE
  • MEMBER
  • 3 POSTS
Last test was 55-61 (when you first start the truck it goes up to 70 then regulates anywhere between 55-61 never below 55).
Jul 4, 2021 at 10:49 AM
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ASEMASTER6371
  • ✓Experienced Mechanic
  • 52,796 POSTS
When it stalls, does the pressure remain at 55? Want to make sure it is not falling off.

Roy
Jul 4, 2021 at 7:37 PM
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