Electric fuel pump died/overheated... why? - JeepForum.com
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post #1 of 17 Old 09-30-2007, 06:28 PM Thread Starter
part.changer
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Electric fuel pump died/overheated... why?

Is it possible that running an electric fuel pump on very low fuel could burn the motor up?

If so, would a mechanical fuel pump be susceptible to the same problem? I think I'm going to go mechanical.

Any mechanical recs other than standard (76 CJ7 304)?

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post #2 of 17 Old 09-30-2007, 06:39 PM
Chrisfol82
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If you had it plumbed in wrong maybe that coudl be the problem. Did you ahve a return line?
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post #3 of 17 Old 09-30-2007, 06:47 PM
Fatman
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Electrics don't last forever.
For mechanical look at Accel or Holley, they're not cheep.
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post #4 of 17 Old 09-30-2007, 06:53 PM
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electric fuel pumps use the fuel in the tank to keep cool...
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post #5 of 17 Old 10-01-2007, 01:39 AM
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Hey P.C. good to see you still working on that Jeep...

I recently replaced my mech with an electric pump (Holley Red), and when I tested it I found that if I did not run a return line, the pump was seriously overheating and appeared to be boiling the fuel. When I re-installed the return line, it ran as cool as ice... I would figure that running the pump dry or low fuel conditions would overheat the sucker as well. I love the electic pump performance, but I HATE the noise... If given the choice again, I would go with a high grade mechanical pump over the electric. Best to you...

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post #6 of 17 Old 10-01-2007, 07:25 AM Thread Starter
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I don't know about any return line on this pump. It's a pretty simple device... one in from the tank... one out to the engine. Am I missing something here?
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post #7 of 17 Old 10-01-2007, 07:37 AM
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a good mechanical pump look at a carter super pump what I use

1978 cj-7 had since 1979
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post #8 of 17 Old 10-01-2007, 12:35 PM
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You are missing the fuel filter... installed after the pump and prior to the carb. The stock filter has a return line (1/4") that goes back to the tank for recycling. This keeps fuel flowing through the pump (since it never stops running) when your carb bowls are full (floats should stop flow). Otherwise, the pump and fuel overheats and causes the pump to fail or the fuel to boil (vapor lock). I have tested and verified that this does occur without a return line.

However if you are going to replace the pump, I would take fuzz401's advice and go mechanical. Either way, you will still need a return line to prevent vapor lock.

Mama Says... Jeeps are the Devil!
***1980 Jeep CJ7 Laredo, 304 V8***
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post #9 of 17 Old 10-01-2007, 09:17 PM
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With an electric pump you definately need a return line. That pump is going to want to pump a certain amount of fuel whether the engine needs it all or not. If your not using enough fuel youll be deadheading the pump. The fuel will basically stop flowing through the line, or going very slow at higher pressure than the pump was designed for. Obviously this is not good for the pump. By putting in a return line you allow the pump to operate within its proper curve and when the engine isnt requiring the full amount of flow from the pump, which it probably never is, it will just be recirculated back to the tank.
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post #10 of 17 Old 10-01-2007, 09:31 PM
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Yep running an electric pump low on fuel or out of fuel will burn it up sometimes. I've burnt one up in a company Ford Ranger by running it out of gas. I never would of thought it, but after replacing the pump in the tank it fired right up.
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post #11 of 17 Old 10-01-2007, 10:00 PM Thread Starter
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All right... I ordered a replacement mechanical pump. Now, I still don't know where the return line will go.

The mech. pump will be up in the engine compartment near the carb, so where in the world is the return line?

(1) Will I have to run a line all the way from my engine compartment *back* to my fuel tank? (2) Does my fuel tank have an extra inlet somewhere for such a line?

ON SECOND THOUGHT: I will be installing this mechanical fuel pump from scratch and have no idea where it goes and how it's to be plumbed. (3) Anyone know of tutorials/pics? I'll have a rubber fuel line from tank to just ahead of the rear axle, a steel line up to the engine compartment (probably up to the mech. pump), then a rubber line into the carb with a fuel filter inline in that section. (4) Is that correct?

Also, as stated above, where is the return line?

(5) What other precautions should I take against vapor lock?
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post #12 of 17 Old 10-02-2007, 11:30 AM
soccerpapa
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mech pump only goes in one place on your engine.

Yes, you will have to run a line back to the tank... see other recent threads on return line for pics.

http://www.jeepforum.com/forum/f8/fuel-return-line-462220/

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post #13 of 17 Old 10-02-2007, 11:43 AM Thread Starter
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Perfect thread... thanks.

The line from my tank to my pump is steel tubing. Does my return line need to be steel tubing as well or can it be rubber?

TO ALL: Please address numbered questions above as well, if you'd like.
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post #14 of 17 Old 10-02-2007, 02:33 PM Thread Starter
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^selfish bump^
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post #15 of 17 Old 10-02-2007, 03:42 PM
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I'd run hard stainless 5/16 from the tank to the pump, and the same along the frame for the return line.

http://www.4wd.com/

I think I paid $39 for a 20' roll.
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