90 f150 , no fuel delivery

Feb 05, 2006 Last reply: 20 years ago 3 Replies
90 F150 .. dual tanks (rear tank leaks , never used)

Truck was run with next to no gas and likely ran dry. Chugged out appx



1000yds from home. Added 3gals but no life. Mechanic frien took a very fast look and determined that theres no fuel pressure at the engine.

We hear the tank fuel pump run, but someome told me there's TWO?



Anyways, crawling over it tomorrow, whats a good sequence of things to check to find the problem?



Thanks, Mike


Your '90 has a pump in each tank. They also had problems with the tank switching valves getting stuck directing fuel to the wrong tank. It is quite likely that since you never used that tank, the valve is now stuck for the one you have been using. The fuel pump cannot pump thru a closed valve. The switching valve is where I would look for the problem.

Lugnut

Thanks Lugnut.. I did see posts in this NG related to the switch valve, but i mentioned the dual tanks and the fact that one tank is holed on purpose. We NEVER use the tank switch since one is dead. If the switch valve is stuck, then i'm betting is stuck in the position its been in for the last year. I wont ignore its existence but my gut says its a longshot.

There are actually 3 fuel pumps on the truck. The low pressure one is in the tank. The one on the frame rail (it's pretty obvious) steps the pressure up.

The low pressure pumps provide enough pressure to actuate the valve that switches between tanks. It's made so that it seals in the fuel return line to the tank that the fuel came out of. It should be obvious why that's needed. Any leaking from one tank to another is normally not a concern, but on your truck it might be.

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