have a 1996 f150 5.0 2wd dual tanks. my fuel has always returned to the front tank no matter what tank im using. wasnt a problem untill my fron tank took a sh*t. so now i have fuel coming out of vent tube cause my fron tank is so full. not real sure how this sys works so any help would be awesome. maybe a quick fix.?.?

 

i have the same problem. i have to replace front pump to fix it. this happens because the check valve is stuck open in the front tank and because the fuel line is inline from the back, fuel leaks into the front tank. I have to fix mine asap. does your truck run fine? i hear your gas vapor canister can get filled with raw fuel if u don't fix it which can cause problems. hope this helps

 

yea it runs great off of the rear pump and it did on the front pump untill it quit. since i just discovered raw fuel in the vent it is possible it could get into the cannister which i hope doesnt happen. thats what i figured cause i was looking for this fuel pump thing on the frame rail that i was told was bad and couldnt find it so yea that helps out alot thanks

 

I have an 88 F150 with 3 pumps, one in each tank and one on the frame rail under the driver's side door and near the fuel filter. I think it was supposed to be a helper pump to put less strain on the other two so that they'd last longer. The idea was that the one on the frame rail would go first and be easy to fix, although it seems that in reality it lasts longer than the other two. I'm pretty sure they elimnated the frame rail pump around your year.

 

I was always under the impression that on the older truck w/ 3 pumps, the problem was in the tank selector valve. But I've yet to actually have that problem personally.

 

Well my report was based off of a long winded Ford/Chevy debate that I had a while back with my friendly sales technician at Napa, so I admit it may be a crock of crap, but it sounded pretty reasonable. I think the tank selector switch was definately problematic, but didnt they also take that frame rail pump out around 96?

 

The valve, not so much the switch. I think they eliminated the hp pump on the frame rail even before that. I am a NAPA fan. There's alot to keep up on, I just found out my 87' 302 AOD has 2 VSS's! 1 on the Diff. for ABS, & 1 on the Tranny for Cruise Control, if it's a single cable Cruise Control Unit. Which must mean there are also "dual cable" Cruse control units. All this was new to me!

 

'87-'89 pump on the frame and one in each tank. The ones in the tanks are low pressure and the frame one is high pressure. '90-'96 they eliminated the frame pump and just put high pressure ones in the tanks. Each tank has a valve that keeps fuel from being pumped into the wrong tank, it doesn't matter front tank or rear each one can get fuel when it's not supposed to. The tank that gets fuel when it shouldn't has the bad valve, and the valve isn't sold separately you have to buy the pump assembly.

 

Oh no harm ment towards Napa. The guy at mine is just a die hard camaro and C10 fan, and whenever I go and ask for a part for my truck it I am guarenteed a debate. Always is a help though and has good pointers.

 

Wadaya gonna do, nobodies perfect. Although I'm still waiting for "JCMS" to screw up! I been here for almost 1K posts...............still waiting!...................