mikebar4

my fuel pump in my 03 z71 with the 5.3 makes an awful noise. it has done this since i had it, about 4k miles. the truck has 35k on it. i never asked the previous owner about it and have lost in touch with him. the truck runs fine but the noise is pretty loud and people always asks me about it. do i need to change my fuel filter? any ideas???????
oh yeah,,,i average around 14.5 mpg with a set of 285s on it.

MT-2500

Start with a fuel filter.
Also a good fuel pressure check may be in order.
MT

mikebar4

just put in new fule filter and still makes the same noise. any other ideas?

MT-2500

Move on to the fuel presure test.
Any hard starting?
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.

97cavalier

Is it like a ring noise? because i have a 99 silverado with the 4.8 and it has a anoying ring and it is the fuel pump. I am going to replace it nd the sending unit soon.

mikebar4

its like a wining noise. cant quit figure it out and i dont have the tools to do the pressure test. might have to take it to a mechanics shop before its over with.

97cavalier

ya, mine does the same thing, it has been doing it since about 30,000 and i now have 100,000 on it and still doing it. I know it is the fuel pump, but just don't have the time to replace it. I am going to do it soon though. It is not that hard you just losen the straps on the tank and reach in there and pull it out.

tykrz

If it's noisy,it's trying to tell you something...like its on the way out. It may last a very long time or it may crater next drive down the street. I find these things always seem to crater out at the most inconvienient time, such as in the middle of nowhere. I'd change it out before you have a huge tow bill to add to the repair.