Will an inline fuel pump work?

WALLACE LADMO

MEMBER
1991 GMC VAN
V8
2WD
100 MILES

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.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 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.

Image (Click to make bigger)