Hi all, I have searched the archives but I'm still haven't really found an answer...so here goes...I have a '93 F250 4x4 351W Dual tanks.

When any one of the tanks reaches about 1/4 full, the engine will act as if I'm running out of gas.(hesitate, loss of power etc.)

I then switch tanks and everything is just dandy. I then go to a gas station and fill the tank that was about 1/4 full, switch back to that tank and again everything is just dandy.

This will happen on either tanks, and each time I would immediately go and top off the tank that was about 1/4 full.

At first, I thought I had water in the tanks ot perhaps bad fuel. Now it's doing the "I'm outa gas" thing when both tanks are full.
I can't drive the truck when this is happening because it has such a lack of power and is on the verge of stalling, not even feathering the gas pedal helps.

I've been stranded twice on the side of the road when this has happened, BUT, both times after sitting about an hour twiddleling my thumbs, I start the truck, and it runs just fine...for a while.

My wife has noted that this has only happened under load, (towing a trailer), and when the outside temperature is about 80 degree's.

Note, I have yet to have the recall on the cross flow fuel pressure regulator done, however it is going to a dealer this week to have the recall completed and to diagnoss this anoying problem...

Any thoughts on this will be much appreciated - I'd like to have a little knowledge about this before I face a service advisor..

Also, does each tank have it's own fuel pump?

Thanks!

 

Most EFI systems have in-tank pumps now.

Sounds like your pumps might be heating up & the lower fuel in each tank allows them to seize. Over time they do go bad (increased friction or electrical motor getting worse), and that may be what is happening now (they heat up faster the worse they get).

If you're one to try to run your tanks down to almost empty your pumps will fail faster due to not having the fuel around them to cool them. If you do change your pumps try to keep your tanks from getting below 1/4 to 1/8 full before filling up to preserve them.

(There is also a possibility you, or someone, filled both tanks up at a station that had a filter blow, and you have a good amount of debris in the tanks. This debris will clog the filter socks up.)

 

thanks for the tips GammaDriver!

update: I took the truck into a Ford dealership to get the cross flow fuel recall completed, and had them diagnoss the loss of fuel pressure I'm experiencing.

Recall work was completed, but they told me tht there was nothing else wrong with my truck. I had it for less then an hour driving, and it did what my original post said.

Very, very frusterating! I told the service advisor how to repeat the symtons -"just let it run/idle for a while and it will sputter and eventually stall."

so does a maojor dealership do this(hands on trouble shooting?)or do they just hook the truck up to a diagnosis computer and if no codes come up that's it?

any advice on how to communicate with a service advisor?

Thanks