[dancin1]

Yesterday I was out in the Jeep and it was running maybe 4 hours constantly, mostly at idle through one of the WMA closeby. As I was comming home, there was a strange humming sound coming from the rear of the Jeep ('91 YJ, 6cyl, 5 sp) I know both the gas tank and the rear differential have a breather, now wondering if maybe it's plugged somehow ? Where is it and how do I tell if it is plugged ? Also, if that can't be the humming, what could it be ?

 

[Signalman]

If I get to low on fuel I can hear the fuel pump humming

 

[Scott-CJ8]

The breather hoses might sing a little bit, they usually don't hum.
It's probably the fuel pump. Once you turn it off, does the humming stop? If it continues, it could then be vapor/pressure in the hoses. If it does stop, then it's probably the electronic pump letting ya know it's working back there.

 

[dancin1]

OK, I just started it up and it's not humming now. Could it have something to do with the heat ? Like i said, it was running for well over 4 hours and it was only 94 degrees here yesterday. I am low on gas though. Might just fill it up and see. Tomorrow I'm getting the locker installed in the front differential, that's a 1 hour trip to 4wd parts in one direction.

 

[Scott-CJ8]

Yep, mine 'talks' to me when it's hot and low on gas too. Usually just shutting it off and restarting quiets it down.

 

[Maladaptive]

I have the same "hum". I tracked it to my fuel pump. Sometimes it is really loud, others not so loud, but it's always there. I thought it meant that it was going out and have been checking into replacing it, and haven' been too excited about the prospect. After reading here, maybe I don't need too?
What is the prevailing opinion on this?

 

[BAP]

just as you posted maladapive....,,,,,,same here !!! ecept mine does it when low and been hot,,,,,

 

[BAP]

mine hummed loud from a cold start and i had well over half a tank of gas in it today even after muliple starts,,,,,i think it,s going to go out,,,----it first started just every now and then after long road trips , but it,s getting more frequent..... and then there was today..

we will see i just hope it dont go out somewhere back in the hills,,--i prob. should just replace it but im also curious, and we all know what happened to the cat....