Fuel Sending Unit Humming

[dancome433]

So a couple months ago my truck wouldn't start, figured out the fuel sending unit wasn't coming on, after a while of me and buddy messing with it, he decided to tap the side of the tank with a hammer a few times, I thought that's stupid it won't work, well guess what, it worked, fuel sending unit kicked on, truck started, good to go. But after a while since then Ive noticed the sending unit hums louder than normal when the truck is idling. I don't drive the truck often due to it being in its project stage, but Ive driven it a few miles here and there nothing too bad and it still continues to run fine, no sputtering or fuel pressure issues. My question is, is the humming a sign of my sending unit going out or is it just me?

[airspeed]

I think you are using the term sending unit as fuel pump?  The pump should make noise but I don't think you should hear it when the truck is running.  When you first turn the key on before the engine starts you should hear the pump cycle for a few seconds.  If it continues to make noise like that you may have to pull it out.  There is a sock filter on the fuel pump that may be plugged.  You may also want to change your inline fuel filter as well, it may be plugged making the pump labor.

 

Remove the left tail light, there is a fuel pump ground wire under a screw, clean that connection.

[dancome433]

I think you are using the term sending unit as fuel pump?  The pump should make noise but I don't think you should hear it when the truck is running.  When you first turn the key on before the engine starts you should hear the pump cycle for a few seconds.  If it continues to make noise like that you may have to pull it out.  There is a sock filter on the fuel pump that may be plugged.  You may also want to change your inline fuel filter as well, it may be plugged making the pump labor.

 

Remove the left tail light, there is a fuel pump ground wire under a screw, clean that connection.

 

Yes, the fuel pump, not sure why I was using the term "fuel sending unit". And yea it does its usual hum when you turn the key, Ill have to check the sock filter on the fuel pump, I already replaced the inline filter not too long ago, so that's good, and when I removed my bed to replace it, I moved the ground wire from behind the tail light to a clean spot on the frame, thanks for the info

[Bmoore2]

Once my truck gets below a half a tank the fuel pump starts humming. Fill it up with gas and I don't hear a thing. I have a new fuel pump behind the seat just in case.

[cruiser54]

If rapping on the tank got the pump to start running once, and now it's loud,  the pump is probably taking a dump soon.

[dancome433]

Once my truck gets below a half a tank the fuel pump starts humming. Fill it up with gas and I don't hear a thing. I have a new fuel pump behind the seat just in case.

 

That could be a possibility being that I haven't filled the truck completely up since I don't drive it much and Ive had to remove the bed, which would be a PITA if the tank were full

 

 

If rapping on the tank got the pump to start running once, and now it's loud,  the pump is probably taking a dump soon.

 

That's what I was thinking, but hoping that it won't,

[JeepcoMJ]

you should be buying a new pump

[dancome433]

you should be buying a new pump

 

That's what I'm thinking, since Ill be pulling it out to check the sock filter airspeed mentioned about, I might as well replace once I'm at it, I'm almost positive its the original since the truck is an 89 with 93k miles,

[mjeff87]

It's a crapshoot, but your pump is beginning to die.  Mine hummed for a year or so moderately, then it got LOUD.  I kept driving it, knowing it was gonna go and one day out of the blue it did.  Loaded it up with crap and drove it down to my storage facilty, parked it and unloaded it and it didn't start.

 

I'd change it sooner than later, especially if it starts getting louder than it already is.

 

Jeff