Humming from the rear... What is it?

My 97 Blazer, 4x4 is starting to hum from the rear. I think it's my fuel pump starting to go bad. What do you think? ...And if it's my fuel pump are there two approaches to fixing it? For example, I can remove it and replace the O-rings (Like one thread talked about, vaguely) or do I have to replace the whole unit? I hear it's kind of expensive.... All comments welcome.

What kind of hum?

When you are driving or when parked with the engine running?

What kind of hum?

When you are driving or when parked with the engine running?


Both... running and parked.

I will verify this tomorrow when it's light out, but I think it's coming from the rear-passenger side.

3 weeks ago I verified that the fuel pressure was okay and it was. My car was a little hard to start. Then this week it's getting harder to start -- and the hum I think is getting louder.

Do warn out fuel pumps start to behaive this way... and then go out all together? I have 116,000 miles on the vehicle.

The only other comment I can make is that last week I had the fuel rail professionally cleaned. Do you think there is a correlation to that work and the noise? I'm just wondering if when they removed the fuel lines they may have caused some sort of wiring problem (resistance issue in the line)??? But that's would be too odd, right?

Might be a plugged fuel filter causing the pump to struggle.

As the new owner of this vehicle, I replaced the fuel filter 4 weeks ago. I also read in another thread that these fuel pumps are naturally noisey and that sometime aftermarket pumps are even louder. (Did you say that?) ...Any other ideas about the wiring or perhaps this noise is a precurser to an eventual fuel pump failure?

My fuel pump emits a high pitch buzz. On my '94 the fuel pump is in the tank. I've been told it is normal.

Yip, it will make a normal high pitch whine most of the time.

I just replaced my fuel pump with an "aftermarket" type and the high pitch electric motor sound is way louder than the OEM.

Mine was too on my 1995 when I swapped it out 4 months ago.

does it make the noise if the key is on the on position and not started?

if so its the fuel pump and yea they are loud for a pump, when i first got mine i thought it was bad but thats how they are, if u put a new filter in and its stuff i should be jsut fine. and at times mines louder too.

if its harder to start like mine is, let the key stay in the on position for like 5 seconds then start the car, it will start right up.

t'

let me know if that works