Dual tank problem
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Dual tank problem
I just bought a 91 F-150 with dual tanks. Everything works great except the front tank. When you try and fill-up the front tank it starts to overflow and the tank is totally empty. Right now I just pull from the rear tank, but it would be nice to get the front one working. Can anyone give me a good starting place to troubleshoot this problem? Anyone had a similar problem?
Thanks, Clayton
Thanks, Clayton
Last edited by striker_wvu; Apr 3, 2005 at 02:30 PM.
Posting Guru
Joined: Jun 2004
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From: Central NY
Have you actually tapped on the tank to see if it was full?
It could just be a bad selector switch, which also switches the tank float signal to the gauge. I beleive that It also switches fuel pump power so it wouldn't run even if it were full.
Popa Tim
It could just be a bad selector switch, which also switches the tank float signal to the gauge. I beleive that It also switches fuel pump power so it wouldn't run even if it were full.
Popa Tim
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Update
Just checked everything out myself. (Previous owner is who told me that tank was empty) Fuel tank is actually totally full. That solves to mysterious overflow problem. When I flip switch to the front tank it reads way past full, but engine sputters and isn't getting gas. I doubt it is a problem with the lines since they join with the rear tank lines. I guess the problem is narrowed down to the selector switch, sender unit, or fuel pump. Is the selector switch ruled out since the level sensor switches between tanks? What is the electricrical unit that the switch unit is wired to? Anyone know a way to if it is the pump or sender unit that is bad?
Last edited by striker_wvu; Apr 3, 2005 at 04:31 PM.
Posting Guru
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From: N. Gwinnett Co. Georgia
It can be the fuel pump relay or the fuel pump as the selector is showing a differential quantity in the tanks. Generally, but not always, this indicates that the selector switch is functioning. I'd think you may have a clogged sock on the fuel pump in the front tank at this point. Does the fuel pump initialize when you turn the key on and can you hear it?
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From: N. Gwinnett Co. Georgia
I'm sorry then, if the relay is clicking, the pump is most probably gone. I had to replace the one in my front tank about 5 months ago. It's not a terribly difficult job. There are two schools to approach it, drop the tank or lift the bed off. I used a tranny jack and a 2x10 and cable tied the tank to it and dropped it, fairly easy job, just loosen the fill tube and strap nuts and drop her. You don't have to come down very far and then you can do the job. If you don't have a Haynes or Chilton's manual, post and I'll either go through it with you or fax you a copy of the procedure. Siphon as much gas out of the tank as you are able to reduce weight and awkwardness. Relieve the pressure on the fuel lines also.
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Posting Guru
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From: Central NY
Since the age of the gas in that tank is unknown, I wouldn't put it back in either.
Actually if you drop the tank you could do a thorough job of emptying it and taking care of any rust issues while you're at it.
If your tank straps are rusty already, pick up a new set along with nuts and bolts for them.
Cheers,
Popa Tim
Actually if you drop the tank you could do a thorough job of emptying it and taking care of any rust issues while you're at it.
If your tank straps are rusty already, pick up a new set along with nuts and bolts for them.
Cheers,
Popa Tim
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I replaced my fron fuel pump on my 90 F150 and I was able to do it without droping the tank all the way down. Just loosen the bolts and the straps that hold the tank down and you should be able to get the pump out without too much trouble.
Fleet Owner
Joined: Jun 1999
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From: Creedmoor, North Carolina
Not to pile on but my front tank pump works but the guage stays in the 3:00 position also.
With a full tank to deal with the bed removal might be a better way to deal with your delimer.
John
With a full tank to deal with the bed removal might be a better way to deal with your delimer.
John
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I'm telling you that you don't have to remove the bed or the tank. Just lower it a little unscrew the retaining ring and pull out the sending unit and pump. Now with the rear tank the bed removal is the way to go. But it is an easy fix for the front tank, took me no more that 45 min.
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I was sure my pump was bad, but I took one last course of action. I ran a wire from the positive on the cigarette lighter to the solid red wire on the dual tank switch. My front tank pump started up and the truck ran. So, the switch was bad. Then, being cheap, I took the switch apart, cleaned the contacts, put it back together, and now it works. Funny. The prev owners also said the radio was bad - I replaced the light bulb. Said the front end needed work - I adjusted the steering gear. That the head gasket was bad because it leaked oil and the cap had milky brown stuff on it- I tightened the valve cover a little and drove the truck more than 1 mile at a time to get rid of the water in the oil. Good truck for a small amount of money.
Junior User
Joined: Apr 2005
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From: Arlington, VA
This is a great thread. I've got a 90 F350 with dual tanks and I had a hell of a time trying to repair the front fuel line coming off the tank. I finally found a repair kit at Advance Auto. Looks like the fuel pump repair won't be too bad when it comes. I'm at 157K miles so it shouldn't be too long...
My radio also doesn't light up. I'll be replacing the bulb soon...
My radio also doesn't light up. I'll be replacing the bulb soon...