Stalling - fuel system troubleshooting

EODTEK

MEMBER
1996 FORD F-250
5.8L
V8
2WD
AUTOMATIC
444,400 MILES

Last year I was experiencing a lagging when running from the rear tank. I replaced the fuel pump and filter with no experience in performance.

Using an 'OBD Link' gift given to me by my son shows that when idling on the front tank the fuel flow rate at.6 gal/hr. When I switch to the rear tank the flow rate increases to 1.1 or 1.2 gal/hr and the engine lags and eventually stalls. Opening the throttle to keep the engine running has no effect. Could there be an issue with a pressure regulator or the 6-port selector valve?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

It is unlikely that this is an issue with the pressure regulator because that is on the fuel rail that is shared between tanks. So if the flow rate is changing between tanks then we could have an issue with the pump but we need to start with checking the pressure on both tanks. Here is a guide that will help with this:

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

Once we know what the pressure is, we can go from there but I suspect you will find the pressure is higher on the rear tank. You have an issue with the engine over fueling which is causing the stalling so if this is only on the rear tank then I suspect the pressure is high.

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

https://www.youtube.com/watch?v=D1AyqeftAmA

Also, I attached the process below on the pump replacement in case you need that as well. Thanks

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