Chick-N-Picker

1989 XJ 4.0 auto 4x4 82,000 miles.

On my jeep I got a year ago this August I'm having a weird problem. I didn't mess with until January

It had a bad fuel pump so I replaced it in January and it fires right up and ran good until about 6 weeks later and the fuel pump went out again.

It have went through 6 NAPA fuel pumps in 6 months. They are marked as Carter but they're still airtex.

Here are my symptoms in a short form. I put a new pump in and it runs just fine for 3-6 weeks then the fuel pump starts humming really loud after driving for a few minutes and if I crawl under and lay my hand on where the unit installs I can feel that sucker vibrating.
Once the humming starts I have 1 day to 2 weeks before it starts cutting off while driving.

I am going to clean the tank really good but what could this be?

Jeep Driver

http://www.1aauto.com/jeep-fuel-pump...mR7BoCW4nw_wcB

Replace it.

Chick-N-Picker

I read that after market ballast resistor aren't any good and it's better to go to a junk yard.

Any way I will replace it. It will probably be Monday as everything is closed now. I'm still cleaning the tank to the max also.

Chick-N-Picker

I just thought if it was the ballast resistor why would it take 3-6 weeks for the fuel pump to start humming and then go bad?

Also how can I check the ballast resistor to see if that is the blame.

Where do I probe? Red where? Black where? Running or off?
I checked the ohms of the resistor with the wires unplugged and Jeep not running and it read .3. I hope I did it correctly. Sorry if I sound stupid. I can do some things but sometimes I need easy step by step.

tech

A ballast resistor lowers the voltage to the fuel pump . the reason the pump goes bad is that it is running to hard and burning it out .

Chick-N-Picker

Ok. Do you know how to check it to see if it's bad? I read on another forum a guy bought a new one and it didn't put out the correct voltage and he burned another pump before he found that out.

Id like to check the one I have now and if it's bad check new one or JY one to avoid going through possibly another pump.

Jeep Driver

Bypass the resistor......wire the two wires together and see if it will run.

But, you may have burned the pump out by now anyway.

Chick-N-Picker

I did use a jumper wire and it still ran but of course the pump was still humming because as you suggested I'm afraid this pump is already gone.

I'm trying to take the hangers off of the tank to clean it. One is off the other is a son. I may just put it back and run seafoam and bypass the resistor. Put another pump in and see if it still goes out.

Turbo X_J

"It had a bad fuel pump so I replaced it in January and it fires right up and ran good until about 6 weeks later and the fuel pump went out again."

I'm thinking it's not actually the fuel pump that is your issue, it should run forever on battery voltage although it may be a little noisy.

1. Check the amperage draw on the fuel pump, could be sky high due to a ground issue.
2.The pump isn't properly mounted, the vibration causes it to lose the electrical connection.
3. Check for broken/damaged/corroded wiring in the fuel pump circuit & connectors.

Chick-N-Picker

How do I check the voltage pull of fuel pump? I just finished putting a factory pump in from a 94 I have and it fired right up. The gas hand just reads in reverse.

tech

I found this about the fuel pump resistor.click the link below.

https://www.cherokeeforum.com/f2/fue...esistor-29636/

Chick-N-Picker

I had already that earlier today but thank you for sharing. It still doesn't tell how to check the voltage. If I just knew where to hook the leads to check the in and out then I could rule the resistor as the cause or not for the failing fuel pumps.

PS funny thing is my daddy was an electrician and he died 2 years ago when I was 20. He had just started teaching me some electrical stuff. Dang I need it.

DFlintstone

It's not the resistor. I WOULD check the pressure on the off chance your regulator is making it work too hard. (free loan from the auto parts store).

Stumped here but see the pic in my sig. >>


Below is the inside of the tank. The black ring you see is the end of the cone that belongs on the end of the fuel return line on the pump assembly. That cone on the metal line holds the bottom of the whole deal in place. That should be fished out, and installed on the metal fuel return line on the assembly. Then you seat the cone into the receptacle in the tank when installing it. The fuel return and pickup are located in a tray inside the tank, so return fuel is available to be picked up at the pump inlet, even when the tank is low or at an angle.

tech

Checking the fuel pump resistor is not that hard you check one side of the resistor and the engine is running you should have about 13 volts and the other side should be about 6 volts lower . so the resistor can be checked at the resistor . hope this helps

Chick-N-Picker

I'll have the pressure checked next time I go by an auto parts store.

I didn't think it was the resistor but I'm going to leave it bypassed for at least 6-8 or until the pump goes out just to see.

It's really annoying but I'm going to start tracing wires and looking for any splits. I'm also going to clean every ground I can. As soon as I get time. I'm really busy everyday as it's farming time. Hopefully this pump will last (for good) or at least until farming is done.