Hey guys...ive been having a problem with my '94 xj6.....a few days ago i was driving and the fuel pump had started making a humming noise...when it primes up, it makes the noise and when its on it as well makes the noise....me and my buddy have been trying to diagnose the problem with new pumps, new canisters and fuel filter and none seem to work....the car runs perfectly fine as well...doesnt run bad at all....So, idk if anyone has heard of any bad electrical issues regarding this problem but we strongly think that there is a bad ground connection to the fuel pump....we tested the connections and with the battery disconnected there is still continuity on the ground cable from the cable to chassis....as well, the battery started leaking acid and we were also thinking it could have been the battery since it was in bad shape...so we bought a new one, had the car on for a long time and nothing at all...noise was gone and we had it on several different times today and it seemed fine until i went to the store and there came the noise again.....this is why we figure it might be something grounding out somewhere but could be wrong....any sort of help and suggestions about what to check and such is GREATLY appreciated....next thing to try next is the fuel regulator and check the alternator to see if its going bad but also could be the valve where the pump connects to inside the canister i believe its like a one way valve but either way any input would be awesome!!!.....thank you folks!

 

Hi:
Well, I'm sure others will have suggestions, and I'm no expert; but... I'm wondering how loud the humming is. The hum of my fuel pump became louder about 3 years ago and I was likewise concerned. Some suggested replacement of a dying pump. I chose to leave it alone and take my chances. Granted, my car isn't run all that much, but the fuel pump works like a charm every time, hum and all.

Did you say that already replaced your pump - taking it out of the tank and everything?

Cheers,
Scott

 

If it happened with a new pump, it might be the RFI protection module that is mounted on the top of the tank (DBC12115). The humming could very well be interference.

Cheers,

Allan

 

He guys...well we actually figured out the problem....after countless hours of testing electrical and such it turned out just to be the fuel pressure regulator...apparently there was just enough fuel to get by the diaphram but was stuck and it was vibrating the diaphram all over the place which was making the whole line vibrate and sounded like the pump was bad or something but yea that was the problem..that car runs so much smoother and u cant even tell its on at idle....but luckily that was it cause i was at witts end with that thing haha....but also, we found out the little resistor/diodes on the wires that connect from the pump to the harness were also bad...once you would connect power to it, the wire would jump like crazy! so, we just snapped those off cause all they are for is for is to silence any feedback noise from the pump to the radio..which still works just fine...but now it works just flawless....i appreciate all the help and suggestions but if anyone else has that problem, check the regulator first.