High(ish) pitch Whine

[grihn]

Okay, this is sort of difficult to describe so bear with me.

I have a '91 explorer. Since I bought it there has been a high-pitched whine emitting from somewhere in the rear. It's not a whine when I'm driving or anything, it's electrical of some sort. I'm really thinking it's coming from the fuel pump area, but I can't be sure. It's loudest on the outside rear of the vehicle. Again, I'm 100% positive it's electrical of some sort. It doesn't appear to cause any issues, everything's working fine...I'm more curious than anything, perhaps a tad concerned that it may cause problems in the future.

Is this something anyone is familiar with? I thought it possibly could be a ground or something, but have no idea where to start looking. Also, if it helps, it only happens when the truck is on, so it won't do it if it's on accy. The whine IS NOT coming through the speakers either if that's helpful.

 

[Horsepwr]

sounds like its the fuel pump if you can start it and have someone put a stethescope up to the gas tank and see if the noise gets louder. That's the only thing i can think of in the rear of the vehicle that could cause that besides your rearend.

 

[mr cribb]

That's the only thing i can think of in the rear of the vehicle that could cause that besides your rearend.

Agreed..^


to the OP.... you had already said it doesn't make noise while driving from the rear end so this is the only thing that makes sense.

 

[Horsepwr]

i kinda want an update im still wondering if he found out what it was.

 

[grihn]

I'm still not 100% sure on what's causing the noise...I was thinking it was something in the fuel pump and that seems to be the consensus here too...I'm not gonna do anything about it unless it becomes a problem because as of now this is my daily driver, and with only having one day off every 2 weeks for the time being I don't have the time or patience to start a huge project.

 

[grihn]

Also, horsepwr, next time I'm at the store I'll pick up a stethoscope and try that...that's a good idea.

 

[Horsepwr]

Also, horsepwr, next time I'm at the store I'll pick up a stethoscope and try that...that's a good idea.

yah its a good thing to have around the house also ive used mine to find misfires bent vavles and intake/exhaust leaks also there just great to have. but i use em on fuel pumps alot since ive come across fuel pumps that work but are so silent you cant hear em with your ear.

 

[2xExplorer]

if you end up changing out the pump, search for the post on here about cutting an access hole under the rear seat for access. Do it and you won't have to drop the fuel tank, but be careful.

 

[grihn]

K, picked up the stethoscope and it does seem to be originating from the fuel pump.

^ Checked out that thread...thanks for the tip. I work 6 days a week and I was gonna let this go until it became a problem since this is my daily driver and the last thing I feel like doing on my day off is dropping a fuel tank! I can make a 2 weekend project with this...tomorrow I'll pull the back seat and cut the hole and next week actually replace the pump and make the door somewhere in between.

Thanks for the help guys...I'll keep you updated on whether or not the sound goes away after I replace the pump...I don't think it's an issue right now, but better safe than sorry, right?!

 

[grihn]

Update....replaced the fuel pump, all is good, the noise stopped, and I seem to be getting better gas milage, so that's a plus. Thanks again for the hint to the thread that you can avoid dropping the fuel tank...very helpful and thanks to the author of that thread...didn't make the little door the same...just took the cut piece of metal and used caulking to put it back on...if I ever need access again I can just cut through the caulking.

 

[Roadrunner777]

I've been lurking, but wanted to say, I figured you could do this in one day, it's surprisingly easy if you can get through the hatch cutting part quickly.

Well done!