Bad fuel pump?
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Bad fuel pump?
I have duel tanks on my 91 F-150 that until today worked fine. I tried starting it this morning to no avail. Once I switched to the rear tank she started right up. Both tanks are around half full and if I switch back to the front tank it will stall. Is there seperate fuses for the dual in tank pumps or am I looking at a bad pump here? Any help on this would be greatly appreciated.
Lee
Lee
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Joined: Jun 2004
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From: Central NY
Although the selector switch on your dash is the more likely culprit, you can't rule out the pump until you actually don't measure voltage there when there should be. I don't beleive there are two fuses, but if there is no voltage to the pump it could also be a broken corroded wire.
A Haynes or Chiltons manual, around $15, would have schematics for you, as well as decent troubleshooting procedures; and would be considered and essential purchase :-)
I wish I could better help you, but I'm at work and left mine home
Popa Tim
A Haynes or Chiltons manual, around $15, would have schematics for you, as well as decent troubleshooting procedures; and would be considered and essential purchase :-)
I wish I could better help you, but I'm at work and left mine home
Popa Tim
Senior User
Joined: Feb 2004
Posts: 292
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From: Kansas City
Although the selector switch on your dash is the more likely culprit, you can't rule out the pump until you actually don't measure voltage there when there should be. I
I just went through this on mine, there is only one fuse for both. So if one tank works, the wiring up to the selector switch is good. It's hardly ever the switch, but you can test it.
The haynse/chiltons are extremely handy, but the drawings for the fuel system electrical are a little weak. I went to the library and used their "alldata" system. It's a subsciption service, the library pays for, so it's free to me. They have detailed drawings, with wire colors, resistance, voltage, all the good stuff you can only get from the shop manual. Hopefully your library has it. If not you can get a personal membership for one car, for a year for 30$, I think. I like free best though.
These fuel pumps are pretty high failure rate, after changing the rear tank, the front one has the 'lets return fuel when not selected' problem.
Posting Guru
Joined: Jun 2004
Posts: 1,781
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From: Central NY
Originally Posted by clstrfbc
Holy double negatives batman!! If there is power at pump, and it doesn't work. Your pump is broke.
I just went through this on mine, there is only one fuse for both. So if one tank works, the wiring up to the selector switch is good. It's hardly ever the switch, but you can test it.
The haynse/chiltons are extremely handy, but the drawings for the fuel system electrical are a little weak. I went to the library and used their "alldata" system. It's a subsciption service, the library pays for, so it's free to me. They have detailed drawings, with wire colors, resistance, voltage, all the good stuff you can only get from the shop manual. Hopefully your library has it. If not you can get a personal membership for one car, for a year for 30$, I think. I like free best though.
These fuel pumps are pretty high failure rate, after changing the rear tank, the front one has the 'lets return fuel when not selected' problem.
Old trucks keep you out of the wifes hair! LOL
Cheers,
Popa Tim
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Joined: Nov 2004
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From: N. Gwinnett Co. Georgia
The pump is the likely culprit, presuming that you have checked the $9.00 +/- relays under the hood in the power distribution box and next to it. Mine failed in the front tank at 239,000 miles. I figure I got my money out of that pump any way you want to look at it. Replacement time was under 4 hours.
