New fuel pump buzzing noise

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by palmer_df0130, Feb 15, 2012.

  1. palmer_df0130

    palmer_df0130 Rockstar

    I installed a new Delphi fuel pump assembly, AC Delco fuel filter, and Delphi fuel pressure regulator this past Friday and now I have a buzzing sound that comes from the pump and travels up the fuel line to the fuel pressure regulator. The truck idles and accelerates fine with no hesitation what so ever. I had replaced the fuel pressure regulator in October with an Autozone one and it made the same sound with the old pump, but went away after driving from NC to AZ. Is it possible there is air in the system or is this a noise I have to live with? Thanks for any help in advance.
  2. palmer_df0130

    palmer_df0130 Rockstar

    Update- The noise seems to be worse in the mornings and gets quieter throughout the day as the day gets warmer. Anybody have any guesses on what it could be? Faulty pump or pressure regulator maybe?
  3. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    Is the pump generating the correct pressure? If I had to guess, I would guess:

    a) out of the blue, you got an extra noisy pump.
    b) You left something (a tool or other small piece) on top of the gas tank that is vibrating when the pump runs.
    c) a piece of fuel line is loose in it's mounting that is creating a rattle.
    d) the pump is a loose in it's mountings inside the tank.

    or something along those lines.
  4. palmer_df0130

    palmer_df0130 Rockstar

    Update-New fuel pump/system buzzing

    I finally had a chance to get the bed off my truck and recheck all the work I previously done. Everything checked out good except for the buzzing noise. I traced to the return line and it I can feel it vibrate from the fuel rail all the way back to the tank. I put my ear on top of the pump and it is not the pump. When I take the vacuum line off the fpr, it doesn't make the sound. It is a brand new Delphi fpr. Do you think I might have gotten a faulty fpr or could it be a possible restricted line?
  5. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    Is the regulator maintaining the correct pressure? Assuming it is the same basic design as my '98 (What year/engine is it, anyway?), the FP is a basic back pressure regulator. I could see it "buzzing" while not necessarily being faulty. As with other similar type things, the noise may not indicate anything, maybe some "crud" stuck in the diaphragm part of the regulator, maybe a spring that is not seated correctly, or who knows. If it is not maintaing the correct pressure, then it shouldn't be too hard to get the vendor to warranty the part. If it is otherwise working correctly, then it would be a question of whether the vendor will agree that the buzz alone is a "manufacturing defect" or not.
  6. palmer_df0130

    palmer_df0130 Rockstar

    Thanks for the replies Mr Shorty. I have not been able to test the fuel pressure, but I assume it is good since the truck idles fine and there is no hesitation when accelerating. It is weird that it mainly does it when it sits overnight or it is cool out(below 60, in Yuma, AZ that is cool LOL), but it doesnt make a sound when it sits at work and the temp gets 70+. Probably nothing to worry about and just will have to live with it.
  7. cjohnson1988

    cjohnson1988 New Member

    Hey there, not sure if your issue is fixed yet. had a similar issue with my 2000 Silverado. Terrible buzzing in fuel system when vehicle cold. went away when vehicle hot; noise changed when unplugged vacuum from regulator. the Noise did not seem to be coming from pump. long story short, when I replaced the fuel pressure regulator, I noticed there are aluminum baffles in the fuel rails; I replaced both fuel rails with units from the autowreckers and noise has gone away.
    Hope this helps.
  8. palmer_df0130

    palmer_df0130 Rockstar

    c.j., thanks for the response. Funny that you replied to this issue. I did seem to get the issue fixed shortly after my last post by getting Amazon to send me a new pump and it had been quite the past 7 months. Now that it is getting back into the 50-60's here at night it's starting the same intermittent buzzing sound, just not as bad/loud as the first time. Now, Amazon is saying they will not replace under warranty and am seeing what Delphi replies back to with.
  9. bazar01

    bazar01 Member 2 Years 100 Posts

    I also changed my fuel pump and FPR early this month on my 2001 Burb. I bought the parts from Amazon and they are AC Delco parts. My fuel pump is very quiet. But I also noticed my FPR was making some vibrating noises. I tried removing and reseating it making sure all the O-rings are in the right places and the clip secures the FPR. It is still vibrating. Fuel pressure is at 48-50 psi. I may need to call Amazon and get a warranty replacement FPR. If they don't warranty it, I may have to bite the bullet and get a factory FPR that is about over $100.
  10. palmer_df0130

    palmer_df0130 Rockstar

    bazar01, I think it may be my FPR also after reading more about it. Mine is a Delphi part and I just noticed today while looking at the Delphi website I noticed that they changed the design of the FPR part#FP10021 to look like the original one that I had in my truck that had the security torx screw on the top of it. The new Delphi I got at the beginning of the year has the top part hollowed out like the other after market FPR's I see on the internet. I am awaiting Delphi's response to see if they will send me the newer FPR since this one is making the buzzing/vibrating noise we are talking about. Let me know if you get yours fixed and I will do the same. Might have to to go the way cj did, but don't want to spend the extra money right now.

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