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Discussion Starter · #1 ·
Here is my problem:
When I start up my Jeep it runs perfectly, but after 5 minutes of my Jeep running, the fuel pump will start "humming" (the normal fuel pump sound only 100x louder). A few minutes after it starts making noise, my truck will start bogging down until it eventually wont even run anymore. If I turn off the ignition for 5 minutes, I can start the jeep back up and it will run perfectly fine for another 5 minutes, then the humming starts again and the problems come back.

The more of a load I put on it the sooner the fuel pump will start humming and the sooner it will start bogging down.

Here is the chain of events I have used to try to fix this problem:
I bought the vehicle w/out a fuel pump. When I bought it the tank was sitting in the back and the previous owner said the fuel pump was bad. I installed a Brand New (not reconditioned) AirTek fuel pump in the tank, replaced all the rubber hoses between the Gas tank and the metal Fuel Lines, and installed a new Fuel Filter. I also cleaned out and flushed the gas tank to make sure it was clean.

Immediately after I installed the fuel pump the problem started happening, so I figured it was a bad fuel pump. I pulled the fuel pump out of the tank, exchanged it for another brand new fuel pump, and bought another new fuel filter for it. After installing the 2nd new pump and new filter, the problem still existed. Exactly the same as before, nothing changed.

At this point I took it to a mechanic who put a fuel pressure guage on it. He let it run for an hour and the fuel pressure never dropped, even though the fuel pump was humming away. However he did not test it under a load, only at idle.

When the mechanic could not figure it out, I went to the internet and got another suggestion, replace the ballast (white plastic block on the drivers side fender). I installed a new NAPA brand ballast and still nothing changed. The problem is still there and it still only lasts 5 minutes before the humming.

Has anyone had this problem before? This is a $400 ride, I am not looking to spend much money to fix it, but if anyone knows the problem I'll definately try anything if i can afford it.



Here are some of the suggestions that I have not tried yet:
- Check the computer for codes while under a load (gas + brake)
- Eliminate the Cadillatic convertor
- Airtek's tech support suggested replacing the fuel pump again cuz it might be a bad pump



HELP PLEASE!!!
 

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I would eliminate the cat. And also try to check the voltage at the fuel pump when you have it running. Check it till it starts to bog down. Are you sure you put in a 12V pump? sign up over at www.naxja.org and do a search there if you are not alrady a member.
 

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Discussion Starter · #3 ·
I would eliminate the cat. And also try to check the voltage at the fuel pump when you have it running. Check it till it starts to bog down. Are you sure you put in a 12V pump? sign up over at www.naxja.org and do a search there if you are not alrady a member.
thanks for the naxja link, i signed up and posted a more detailed version of my problem:

http://www.naxja.org/forum/showthread.php?t=984458

I will try to check the voltage, just gotta track down a multimeter. also i went to autozone and asked for a replacement fuel pump...thats the only one they sold so it should be a 12v one?
 

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Sound like your pump is getting clogged up. Time to dropp the tanks and pull the pump and filter and put new in and call it a day.

Rust or dirt in the tank, so maybe a new tank or clean it up some.


Have you checked the do daddy on the fender wall under the hood. Ceramic block that controls the fuel pump hum deal. has two plugs on it where the fuel pump hot wire runs to it it adjusts the voltage to the fuel pump to keep them from burning up, it's like a $5 part.
fuel ballistor I think?
Someone chime in with the name of it, brain fart:fish:
 

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minibeast, did you even read his post? you suggested exactly what he says he has already done...

since you dont have a multimeter, its safe to assume you have not checked grounds yet...do that before going on to anything else...

and engine under load or idling should not make a difference to the fuel pump, it pumps the same amount regardless, and the excess is returned to the tank...well, thats the most common system, anyway, and since I dont know JeEps, I could be wrong on that one...
 
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