Kimocar

I just replaced my fuel pump. (91 Cherokee, 4.0L F.I.) After about 5 minutes of running a very loud "whirring" sound develops from the pump and tends to get louder the longer it runs. I am suspecting a back pressure issue but I am not an expert in F.I. systems. Any suggestions?

Thanx Guys.
Dave

SlapHappy

Did you get one of those Airteks (sp??)?

nascar2496

i hope not, those are garbage.

my jeep has an aftermarket pump, not sure what but it makes a loud whining/electrical buzz at idle. if/when it goes im getting a mopar one. I never cheap out on fuel pumps. i did it once and i had to do the job twice cause the new (airtecks?) pump had a bad check valve. not to mention this was on a 86 camaro where the rear axle needs to be removed to drop the tank. i was not happy.

Kimocar

Thanks guys,
Yes it was an airtex pump...but the question is have you experienced this specific problem - ie very loud hum or whirring from the pump? And when I say very loud I mean you have to turn the radio up it's so loud.

Would incorrect return pressure cause this?

More thoughts from anybody.

SlapHappy

Yeah...I have the same problem with it (Airtex) Loud as all get out, whirs, hums, buzzes and gets worse when the tank starts to get towards empty.

I had to settle for it when I was stranded, I have a bosch replacement in the garage, just haven't gotten around to replacing it.

offroadnut36

I have an airtex and it really doesn't hum all that loud, when it does hum.

G'Pa

Hi Dave,
I just joined the forum as I recently bought a '92 Cherokee for my wife to use as a "bush buggy" to haul tools/lunch etc to our back woodlot. It ran like a charm driving it home (60 miles) and the first few times around the yard. Then yesterday, after driving 100 feet or so the fuel pump suddenly started to buzz/whine loudly!

I read all the replies you got...some good info but I don't see what your final solution was?

I see other stuff on the net like "My Jeep Cherokee's fuel pump has been whining for at least 3-4yrs now with no problems." and "old fuel pump made loud noise.new fuel pump from napa is the same after driven in hot weather.is ok when started cold or driven in cool weather.fuel filter is new also.1996 jeep cherokee 4.0 ltr engine.", also some guys talk of adding something (Trans fluid) to gas "to lube the pump".

Would like some suggestions before I spend a lot of time and money on the problem

Thanks, Barry

TbDk

In December I had issues with holding fuel pressure once the engine was off. I had to prime my jeep every time I wanted to drive or I had long cranks. I replaced the filter/pressure regulator first with no change. Then I replaced the fuel pump. That pump lasted all of 1 week. Then the issue started again. So I want back and exchanged the pump. The new pump was extremely loud, just like you guys are saying. I put that pump in and drove it around since January. Pump was always way louder then expected, but it held the pressure. Then about 2 weeks ago the issue came back. That pump failed too. I finally was able to get the stores to take the parts back and got the entire assembly from oreilly. The one where u just drop it in. So far all is working great with a nice quiet hum.

Fuel pumps have a mind of their own. Getting loud is a sign of a failing pump. The problem is that only pump knows when it's going to stop working. It may last years or only days. I would personally take it back and get a different part or get one from the stealership(yes I stole that it sounds good).

lookin2wheel

My '91 does it as well. As far as I know, its the origional pump. But its only loud every so often. I do have the occasional long start. I turn the ignition on, then off, then start my Jeep. It will start right up 9 out of 10 times with just 1 -2 turns of the motor. So I never really gave it much thought. Been running it like that for over a year.

G'Pa

My research (here and other sites) has produced confusing results:
-"the pump is about to die"
-"my pump has been noisy for 4 yrs"
-"I replaced the pump..problem solved"
-"I replaced the pump...noisier than old one!"
-"It might be the ballast resistor"
-"a '92 doesn't have a (fuel pump) ballast resistor"

My Jeep starts and runs fine so, since I am not a mechanic (no service manual), I'm thinking to just ignore the noise until/unless more symptoms arise. In case I DO have to replace the pump...does anyone have a recommendation for BEST brand to choose?

Tks,

AVjeeper

I replaced my 20yr old failing fuel pump with the Autozone fuel pump and it makes a loud whirring noise. I wans't about to drop the tank again so I put automotive sound absorbing mat under the carpet in the cargo bay. This helped a little. If I ever drop the tank again, I'll replace it with high end brand.

G'Pa

Thanks for the insight....what would you consider a GOOD brand name?

BTW...your '89 must be different than my '92 (??)... it is possible to replace the pump without dropping the tank.

winstontim

I have put two in my jeep in the last two weeks and it hums very loud also when I stomp on the peddle it stumbles and has a hard time with fast execration. any ideas? bad fuel pressure reg. or tps?

F1Addict

It is quite possible that it's your ballast resistor. The only purpose for that little failure-prone, ceramic device is to quiet the fuel pump. I know that there's a test procedure for it but it's late and I have to sleep. Have a quick search, I'm sure something will pop up. Testing is free and may yield the answer to your question.

F1Addict

That's because it's probably not running, LOL! (sorry, half-asleep humor at AirTex expense) Goodnight.