Buzzing fuel pump?

Discussion in 'Technical' started by zac_du_preez, Sep 15, 2007.

  1. zac_du_preez

    zac_du_preez A.K.A. PreeZ

    Just driving the old girl home and noticed that there was a loud buzzing noise in the rear of the car everytime i put my foot on the go fast pedal. I have heard the buzz of the ?fuel pump? before when i nearly stall the car but never this loud and so often...

    PLanning on going on a cruise to the coast and then again tomorrow to see the olds - should I worry?
  2. ZX2NV

    ZX2NV Z Racing Evolution

    Hell yeah replace it as soon as possible.

    If in doubt rip it out a $300 odd dollar pump is a small price to pay compared to a rebuilt VG30 engine


  3. MikeZ

    MikeZ Blingz my thing

    Replace or repair your FPCU

    Check out the tech section for details on opening up and checking your Fuel Pump Control Unit (FPCU) for burnt our transistors. It is a common cause of the fuel pump going into 100% flow mode. Normally the flow is adjusted according to fuel load dependency.

    If you have access to someone else's Zed, swap over the FPCUs to check that this is the problem. If it is, you can solder in the component yourself and it is a $2 fix. No need to replace the fuel pump!

    The tech section reveals all.

  4. zxdreamer

    zxdreamer Bake 'em away toys

    my fuel pump is buzzing constantly ... but now my sub drowns that out :biggrin: problem fixed
  5. SedatZX

    SedatZX Tyranus

    You mean problem ignored till you blow your engine :)
  6. zxdreamer

    zxdreamer Bake 'em away toys

    lol i got more important problems in my Z to fix first ... it is on the list though
  7. JamesZX

    JamesZX POZEST

    would this cause a zed to run rich?? fark... i have been hearing this too... but i thought maybe it was because i took out the carpet shelf thing covering the pump (2 seater) .. i thought the carpeting would of drowned out the noise before and it was normal.... it buzzes everytime i boot it at a certain rev in each gear.... BBZZZ:eek: :eek: :eek:
  8. JamesZX

    JamesZX POZEST

    Where can i get a bigger fuel pump... and whats the recommended pump for a 300zx TT? (2 seater if it matters?)
  9. fuzz300

    fuzz300 Member

    i seem to have this problem intermittently; somedays it does it. others it does not.

    can anyone advise what the implications are for the engine if the Fuel Pump is running at 100% on open throttle.....?

    will it just increase fuel consumption and run rich or cause more sinister effects?
  10. ugame

    ugame user #1

    Pump in my car buzzes too but I just assumed After Market Pump (bosche renouned for the buzzing).

    Guess i need to check it out then.

    ZDUCTIV Active Member

    Stock TT fuel pump is recommended. Good for up to 700whp.

  12. rollin

    rollin First 9

    stock TT fuel pumps are that good? cool. i was thinking i might have to upgrade mine to go with my new engine but i think i might just replace it with new OEM
  13. pexzed

    pexzed Forum Administrator

    I have a spare FPCU you can try if you are close, or I can bring to the cruise if you are coming along.
  14. 300zxt

    300zxt Well-Known Member

    Dual 255lph walbro fuel pumps ftw

    ZDUCTIV Active Member

    To achieve what exactly.
  16. Ascension

    Ascension Active Member

    As far as I know folks from a engine running point of view it's not a problem to have the pump running 100% all the time, as all that's happening is your fuel pressure regulator is maintaining a certain pressure and the excess is re-directed back to the tank. It's not going to make your car run rich or give you bad econony. Unless you have other problems like leaky injectors of course.

    The only concern is that it's not normal, so it's worth checking out just to find out what's going on.

    My pump seems to run full ball all the time since I changed to an aftermarket ECU, and I was told it was fine.

  17. 300zxt

    300zxt Well-Known Member

    Errr, to pump enough fuel to flood a small village! :p

    Seriously though there are many benefits to running dual fuel pumps, it takes the entire load off one fuel pump and you can use a single pump to prime a split tank and then the second one to pump from there. Or you can use one pump for one side of the fuel rail and the other pump for the other side etc It's not practical for anyone under 500rwhp really but that's beside the point! :)
    Last edited: Sep 18, 2007
  18. pexzed

    pexzed Forum Administrator

    That's not exactly true, the fuel pressure regulator controls how much restriction is placed in the the line running back to the tank. It receives vacuum/boost and adds removes restriction thus varying the fuel pressure depending on the vacuum/boost the pressure line sees.
    If you increase the incoming fuel pressure, it won't affect the reference vacuum/boost the regulator sees, so it won't take into account and adjust to reduce fuel pressure.
    We did this on Dyno Day in 2005 to R33ks Z, who was running Lean. We upped the fuel pressure to 12V Constant and pressure mixture became normal.

    In short, there is no way our fuel pressure regulator can be made aware that the fuel pump is running flat out, it just adjusts fuel pressure based on what it sees which is manifold pressure or input from the PRVR system.
  19. Ascension

    Ascension Active Member

    "In short, there is no way our fuel pressure regulator can be made aware that the fuel pump is running flat out, it just adjusts fuel pressure based on what it sees which is manifold pressure or input from the PRVR system."

    I never said it can detect what the pump is doing, but I think we are on the same page anyway. :)

  20. zac_du_preez

    zac_du_preez A.K.A. PreeZ

    Is it just me - I can find the article to check if mine is broken.... links someone?

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