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Ford expert, ASE Certified Technician
Category: Ford
Satisfied Customers: 10370
Experience:  30 yrs,experience shop owner,
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1989 Ford F250: the dual tank fuel system..cylinder..2wd

Customer Question

I need someone who is an Expert and very experienced with the dual tank fuel system on a 1989 Ford F250 6 cylinder, 2wd truck. I have spent significant time and money trying to fix the problem, and no one seems to be able to do it. Is there anyone out there who feels they have the expertise to assist with this issue? If so, please respond and I will direct my lengthy question to you.
Submitted: 5 years ago.
Category: Ford
Expert:  Ford expert replied 5 years ago.
Welcome to just I'm here to help you and your 100% satisfaction is my goal. Go ahead with your question?
Customer: replied 5 years ago.

I have an 89 F250, 6 cyl (4.9L (i think), standard trans. It has two gas tanks. It has a switch on the dash to switch between the front and rear tank. The truck runs great off the front tank, but NOT the rear tank. I did some research and learned this year/model truck had a recall years ago for a condition that would somehow cause an overfill condition where the gas from the front tank would be returned to the rear tank, and cause the tank filler tube to fill, then when the rear gas cap was taken off, gas would spill out of the rear tank. I do not believe my truck ever received the recall repair, but the dealer told me it had.


Anyway, when I try to run my truck from the rear tank it begins to sputter and die out as if there was no gas. However, it will at times run for quite a while before this happens. And the gas gauge in the rear tank never seems to show less gas. But the front tank, even when I am not running off the front tank, is using gas. So I think the "dual fuel resovoir" or whatever the recall was, was never completed and is contributing to the problem.


So I will be running off the rear tank and all is fine. Then the truck will begin to die out, sputter, and will die (as if there is no gas), if I do not immediately switch to the front tank. If I do switch to the front tank, it will run fine. If I then switch to the rear tank, it will run fine for a short time and then the same thing will happen.


I have spent a lot of money having fuel filters, high and low pressure fuel pumps, etc changed. I even drained the rear gas tank and put in new gas thinking maybe the gas had been in there so long the gas was bad. I added some gas additive and it did run very well for a week or so. But like I said, the gas never seems to go down in the rear tank. Anyway, I am clueless at this point and hope you can help. Thank you

Expert:  Ford expert replied 5 years ago.
see if there is an adiitional check valve on the rear tank fuel lines , if there is try running the truck with it removed they tend to clog over time
Customer: replied 5 years ago.
Thank you, XXXXX XXXXX do I find this "check valve", and what does it look like? Are you suggesting there may be some type of added after market valve? Or is there in fact a valve and I just need to check if it is clogged?
Expert:  Ford expert replied 5 years ago.
Yes that was actually what the recall was at one time was to Install a check valve , when the engine dies and it will not run any further on the rear tank we need two checked to see if we have fuel flow coming from the rear tank or not , and if we do not then we need to see if there's power going to that transfer pump in the rear tank
Customer: replied 5 years ago.
OH, ok, a check valve to prevent overfilling of the rear tank and the resulting fire hazard I assume? But you still not tell me where to look or what it looks like? Will it be along the frame rail, in a fuel line, and look like a small cylinder, or what? Thanks again
Expert:  Ford expert replied 5 years ago.
Customer: replied 5 years ago.
I cannot seem to find anything similar to a check valve. could this indicate the recall was never completed? Especially since the recalll was to correct the overfill problem in the rear tank and the same thing seems to occurring now. What do you think?
Expert:  Ford expert replied 5 years ago.
Yes i would say it was never updated