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Fuel Pump is LOUD

Lucas

Lucas

NAXJA Forum User
Location
ZOO YORK CITY
I was having some starting problems after my last trip offroad and I traced it down to my (abused and dead) battery and my starter relay. A new redtop and relay later, I was on the road, but the fuel pump would not prime sometimes (I was listening for the humm) when I turned the key in the ignition. So I swithced the relay for the aux fan and the fuel pump (same part ###s, I think) and everything was fine, except now the humm of the fuel pump is really loud. Im not annoyed by the sound, im just worried that its going to go out on me. Anyone else have this experience?

I read a long time ago about some guy who had a noisy fuel pump in his explorer, and he fixed it by running some 2 stroke motorcycle oil through the tank. Any thoughts?
 
This is a tough question to answer. I still have my original fuel pump on my '90 at just over 300K miles. It has been loud for about the last 7 years. The way I feel is, as long as I can hear it, it's just fine. As always, YMMV.
 
My stepson's 93 had a loud pump, but it kept going for quite some time. My guess is that you needn't worry unless you notice that it is getting louder. It's a matter of judgment how much louder is too much, though. In our case, when it reached 180+k, the sound got much worse (more like a scream than a hum), so I replaced it. But it ran fine despite the noise.

My only other concern might be that if the pump is getting badly worn and drawing more current, it might be shortening the life of the relay contacts, so if you decide to experiment with pump longevity, I suggest you have a spare relay on hand.
 
My pump in my 88, got loud about 2k ago, now it won't hold enough pressure to run the engine. But, it does have 255k on it. So I think I might have gotten the moneys worth out of it.
 
Loud noises

I have had a similar problem with a fuel pump and it just kept going strong but loud. Drove my buddies nuts everytime we got in the van "Do you think the fuel pump is going bad?" I wouldn't recommend putting 2-stroke oil in as it may gum up many of the emissions sensors you have. There are other products for cleaning and treating the fuel system. I like the BG stuff but its more expensive ($20.00 a can).
 
I put a new fuel pump relay (knock on wood, it bit the dust IN the autozone parking lot) and it fixed the REST of my starting problen, and surprisingly, my fuel pump is a little less loud. Thanks for all the help guys, Ill let you know if I have to replace anything related in the future. Also, are all the relays in the fuse box the same, or are there fundamental differences between them? Could I pick them up cheap from say, radioshack?
 
Ok, 2 hours into a long higway drive, and 1/2 into a fresh tank of gas my jeep started to sputter at 70mph. I pulled over and parked, cut her off, and now she wont start. The fuel pump, which has been MOANING, is not so loud when trying to start up anymore.
basically it just turns and turns and turns. There IS pressure in the fuel lines though, and there is spark. The CPS is only about 20k old though. I dicconnected it and reconnected it , but it didntt do anything. Any reason to suspect the fuel pump as the culprit?
 
How are you testing pressure? Is there "pressure" in the fuel manifold, or just fuel?

The EFI requires about 40 psi to function. A weak fuel pump may push enough fuel to squirt out if you depress the Schrader valve on the manifold, but not be enough to provide fuel for the system. Did you check it with a pressure tester?
 
When ever I let the air out of the rear pass tire it always sounds like air is still leaking when I'm done. but it appears that the noise is my fuel pump... I was begining to worry about it and I will probably go pick up a spare and carry it with me in the parts bucket...

Ken
 
I just tested to see if there was any sprurting out of the fuel rail (I was on the side of the interstate). I picked up a fuel pump from autozone (Master LL warranty) along with a strainer. I guess ill tear into that tomorrow unless you guys have any other suggesteions.
 
My fuel pump gets really loud when I've been off-roading for a while. I usually can't hear it, but when it starts, the only way to make the noise go away is to let the Jeep sit and cool down. Have you guys seen this also?
 
Okay, I might be totally off my rocker here, but my fuel pump USED to be loud. I did a bunch of work to the jeep and drove it for almost 2 years without having to to anything but oil changes....I never realized that after doing all that work that the fuel pump noise went away.
Today, I changed the thermostat back to a 195°F thermostat(I had a 160 in there....ya I know it wasn't a great idea, but it always worked well in my old cars). Lo and behold...the fuel pump noise came back with the rise in engine temperature!

Weird huh? It's almost as if now that my jeep isn't gobbling gas like crazy there's a little backpressure in the fuel line again.

Like I said, maybe I'm crazy.
 
Just crazy enough to resurrect an 8 year old thread! Guess that means you know how to search though.

You didn't give any pertinent info on 'the jeep' such as what YEAR it is. Some years are louder than others.
 
sorry, "the jeep" is an 89 cherokee. And as far as resurrecting threads instead of starting a new one over and over again, well. I just prefer not to add to thread clutter.
 
I have a 1990 XJ, mine hums, and gets increasingly louder with engine temp. Another guy I talked to said his has been humming for 4 years.
 
Mine Hummed for a couple of years and and then stopped working. I changed it and the noise stopped. Now the only problem is my fuel gauge stops reading at a quater tank so I dont know how far I can go before i run out of gas which has happend a couple of times.:gee:. I need to fix it but dont really feel like pulling the stupid pump again.
 
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