Will an inline fuel pump work?

1991 GMC VAN

100 MILES • V8 • 2WD

WALLACE LADMO

MEMBER
1 POST

Engine starts rough for about a minute then smooths out but has irregular idle when warm. It has a dead spot right above idle on restart. I just discovered it has an inline fuel pump instead of an in-tank one. Is that the problem, could that ever work? Every thing new except the TBI.

Dec 3, 2022 at 8:49 AM

JACOBANDNICKOLAS

✓ASE Certified Mechanic
110,193 POSTS

Hi,

If the pump is properly installed and provides the fuel pressure needed, it should work. Have you checked to see if there are any diagnostic trouble codes?

This vehicle has an OBD1 system which doesn't require a scan tool. All you need is a short jumper wire or even a paper clip. Follow the directions listed below and let me know what you find.

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Also, here is a link that explains how to test fuel pressure. On this vehicle, you will need to place a T in the fuel supply hose under the hood and then attach a pressure gauge to that T.

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

I attached the directions below specific to this vehicle. They include the manufacturer's fuel pressure specifications.

Let me know.

Take care,

Joe

See pic below.

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Dec 3, 2022 at 11:45 PM

Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.