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New fuel pump buzzing noise

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

  1. palmer_df0130

    palmer_df0130 New Member

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    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.
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  2. palmer_df0130

    palmer_df0130 New Member

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    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?
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  3. MrShorty

    MrShorty Moderator

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    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.
    #3
  4. palmer_df0130

    palmer_df0130 New Member

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    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?
    #4
  5. MrShorty

    MrShorty Moderator

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    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.
    #5
  6. palmer_df0130

    palmer_df0130 New Member

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    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.
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  7. cjohnson1988

    cjohnson1988 New Member

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    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.
    C.J
    #7
  8. palmer_df0130

    palmer_df0130 New Member

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    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.
    #8
  9. bazar01

    bazar01 New Member

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    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.
    #9
  10. palmer_df0130

    palmer_df0130 New Member

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    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.
    #10
  11. cjohnson1988

    cjohnson1988 New Member

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    Funny thing, I bought my first FPR online for cheap (delphi), because the original was leaking; it was after that my truck started making noise. I thought because it was cheap, aftermarket, and the last thing i replaced that it was the cause; so i Sprung full retail at my local GM dealer for the oem part (ACDELCO). THE DELPHI AND THE ACDELCO FPR LOOK EXACTLY THE SAME. I installed the part and the noise persisted. It was a month or two later of living with this embarrassingly loud noise(28.F up here in Canada) that i replaced the fuel rails. immediately noticeable results (I could shake the fuel rails and hear a rattling inside).
    #11
  12. palmer_df0130

    palmer_df0130 New Member

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    Did you replace both rails or just the drivers side one?
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  13. cjohnson1988

    cjohnson1988 New Member

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    I replaced both: It stood to reason that if one fuel rail was constructed a certain way, the other should be the same and might suffer the same affliction (found to be the case after the fact). I stopped in at 'Pick-n-Pull' (no advertising intended) and removed both fuel rails as one piece (minus injectors as would be billed). The damage: $17 plus tax; no guarantee that's what you will be billed, but for around that price, it's worth a gamble. beats the hell out of $170+.
    #13
  14. bazar01

    bazar01 New Member

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    Glad I read your post before I spend on a dealer FPR. It's a little steep for over $100 from the dealer.

    So you are saying there are baffles that can break inside the fuel rails? I wonder how the baffles can break when I just replaced the FPR. I can swear that the vibration is from the FPR because I can feel it when I touched the metal housing.
    #14
  15. cjohnson1988

    cjohnson1988 New Member

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    No idea what happens, just sharing experience and observations on my own vehicle; I have not dis-assembled fuel rails as of yet. If I find something out later on, i will post findings.
    #15
  16. palmer_df0130

    palmer_df0130 New Member

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    Ok, I will be getting a new fuel pump from Amazon under warranty. The email I received from Delphi in response to the FPR vibration/buzzing is due to a fuel pressure problem. The pump I am getting ready to replace fixed the noise for the last 7 months and I will see if this new one will do it for good. I will let you all know how it works out. Estimated delivery is Monday and will hopefully get it in that night and will see if it makes noise after sitting over night. Crossing my fingers.
    #16
  17. cjohnson1988

    cjohnson1988 New Member

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    063.jpg
    Fuel Rail assembly
    064.jpg
    Retainer. NOTE: the fuel rail was never meant to be dis-assembled; this is merely destructive investigation.
    065.jpg
    rail with end cap prior to removal
    066.jpg
    rail with end cap and baffle removed
    067.jpg
    baffle and source of noise. part is flat and isolators keep suspended in rail
    068.jpg
    end cap
    069.jpg
    wear indicates baffle was hammering on end cap.
    #17
  18. Scottg

    Scottg New Member

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    99 Silverado buzzing


    I have the exact same problem on my 99 Silverado. Have tried both aftermarket FPRs and AC Delco with the same results. Both have the buzzing and vibrate the fuel line. Its not the fuel pump making the sound. I can feel the FPR vibrating with the truck running, and it stops when I remove the vacuum line from the FPR. Truck runs great but the buzzing is very annoying. This also only occurs when the outside temp falls below approx 50-60 degrees. Does not happen when the weather is warmer. Mechanic says its fuel pump but I'm skeptical. Your posts state its the fuel rails. Can you confirm that was the problem? Please let me know. Much appreciated.
    Last edited: Oct 14, 2013
    #18
  19. palmer_df0130

    palmer_df0130 New Member

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    Scottg, I wound up putting the cheaper BWD FPR that I had in it orginally before the new fuel pump and Delphi FPR and it has been good since. Not sure if it will fix your issue or you might have to go with the new fuel rails as mentioned in this post. Let us know if you get it fixed.
    #19
  20. Scottg

    Scottg New Member

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    I appreciate your quick response. Going to check the fuel pressure first to see if the pump is good. If not, I'll go after the fuel rails. Will let you know what I find.
    #20

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