Results 1 to 7 of 7

Thread: Fuel pump popping noise

  1. #1
    CF-oholic! fla's Avatar
    Join Date
    10th September 2004
    Location
    Middx
    Posts
    6,598

    Fuel pump popping noise

    Strange one here - sometimes (and there seems to be no discernible pattern to this) on cranking the engine there will be a pop from the side of the car and the car then just continues to crank for a while - maybe about 4 or 5 more turns. Sounds as if the fuel pump momentarily loses power and shuts off only to start up again. The car then fires and runs normally.

    I installed a check valve about 12 months ago in the fuel tank to sort the 'long cranking when warm problem' so i'm not sure if its related. Not really sure what to look for, i'm thinking of checking the wiring to the fuel pump for breaks, maybe remove the check valve, cant think of anything else tbh

    Any suggestions???
    Hasan
    VR6 Auto to manual conversion, beige leather, aircon, TT comps, blue dash lights & switches, Koni TA/Nothelle springs, OBD2, 264 cams, Schrick

    my car

  2. #2
    CF Nutter fendervg's Avatar
    Join Date
    13th June 2009
    Location
    Dublin, IE
    Posts
    2,110
    Sounds like there could be an air lock in the system that then clears - I'd have a good look at the pipes around the fuel filterand change the filter if it hasn't been done recently. Is there any smell of fuel during this?
    ____________
    fendervg

    93 Corrado VR6
    Members Gallery

  3. #3
    CF-oholic! fla's Avatar
    Join Date
    10th September 2004
    Location
    Middx
    Posts
    6,598
    Good call Fender, will do. Changed the filter about 10 years back so perhaps worth changing again
    Hasan
    VR6 Auto to manual conversion, beige leather, aircon, TT comps, blue dash lights & switches, Koni TA/Nothelle springs, OBD2, 264 cams, Schrick

    my car

  4. #4
    ⋆⋆ CF Member ⋆⋆ vw rule's Avatar
    Join Date
    9th February 2013
    Location
    Bournemouth
    Posts
    1,508
    Quote Originally Posted by fla View Post
    Good call Fender, will do. Changed the filter about 10 years back so perhaps worth changing again
    I'd definitely get the fuel filter changed especially if it hasn't been replaced in 10 years, as the paper/mesh filter itself inside will possibly break up, and can lodge partially obstructing the fuel outlet, which is when you may hear the popping/rattling noise, as it moves around and then suddenly clears.

    Ideally you should replace your fuel filter once a year, or every 12k to 15k miles, Main Dealerships change them possibly every 25k or 30k, but that's on a company car that's used regularly and will soon do that mileage.
    On our Corrado's it won't hurt replacing the fuel filter every 6k or 8k or once a year, especially if it's not used regularly.

    Relay with number 167 stamped on it is for the fuel pump, the main live feed wire is red/yellow which also goes to fuel pump.

    You should have constant 12v power to fuel relay and fuel pump, when cranking engine via key plus once engine starts.
    Also you need correct fuel pressure in fuel return line from injector rail to fuel tank,
    basically should be like a constant syphon effect, helped by the fuel pressure regulator which should maintain a pressure in return line back to fuel tank,
    if you get a break in this syphon flow it'll effect starting engine.

    Crank engine over you should be able to feel the fuel relay click on, and then off once you switch ignition off.
    If you hear/feel the relay going mad and clicking on/off when cranking engine, then clearly something is wrong with your electronics.


    Hope this helps

    Si
    Last edited by vw rule; 12th October 2019 at 8:21 PM.
    Had MK2 1.8 Scirocco Scarla 1998 to 2002
    had it lowered on original wheels,
    K&N air fitler and Janspeed exhaust system.

    Now have 94 M reg Corrado 2.0 16v since 2002 still got it, been off the road now since early 2015
    hoping to get it finished this year.

    Also have a 2015 Seat Ibiza TSI i-tech as my daily driver. Plus I'm on The SEAT Forum.

    Link to 16v torque settings & ECU pin locations.
    http://the-corrado.net/showthread.ph...fuel-pressures

  5. #5
    Regular Bauhaus's Avatar
    Join Date
    5th July 2004
    Location
    South East Essex
    Posts
    161
    Quote Originally Posted by vw rule View Post
    I'd definitely get the fuel filter changed especially if it hasn't been replaced in 10 years, as the paper/mesh filter itself inside will possibly break up, and can lodge partially obstructing the fuel outlet, which is when you may hear the popping/rattling noise, as it moves around and then suddenly clears.

    Ideally you should replace your fuel filter once a year, or every 12k to 15k miles, Main Dealerships change them possibly every 25k or 30k, but that's on a company car that's used regularly and will soon do that mileage.
    On our Corrado's it won't hurt replacing the fuel filter every 6k or 8k or once a year, especially if it's not used regularly.

    Relay with number 167 stamped on it is for the fuel pump, the main live feed wire is red/yellow which also goes to fuel pump.

    You should have constant 12v power to fuel relay and fuel pump, when cranking engine via key plus once engine starts.
    Also you need correct fuel pressure in fuel return line from injector rail to fuel tank,
    basically should be like a constant syphon effect, helped by the fuel pressure regulator which should maintain a pressure in return line back to fuel tank,
    if you get a break in this syphon flow it'll effect starting engine.

    Crank engine over you should be able to feel the fuel relay click on, and then off once you switch ignition off.
    If you hear/feel the relay going mad and clicking on/off when cranking engine, then clearly something is wrong with your electronics.


    Hope this helps

    Si
    There is some slight misinformation here; there should be hardly any fuel pressure to speak of in the return lines.
    Pressure is the resistance to flow, (higher the pressure the slower the fuel flow which is not what’s needed in the return line), so if there is any pressure in the return line you may have a serious blockage in the fuel tank vent which could be the popping sound of it releasing pressure.

  6. #6
    CF-oholic! fla's Avatar
    Join Date
    10th September 2004
    Location
    Middx
    Posts
    6,598
    Well the fuel filter change has made a big difference - no sluggish starting and so far no popping noises again!
    Got the wrong size from Bosch which according to their part numbers was correct. Returned it and bought one from GSF (Mann) fits perfectly.

    Used some silicone grease on the clips.

    Longest part was locating the trolley jack in the right place whilst having space for the stand AND having clear access.
    Hasan
    VR6 Auto to manual conversion, beige leather, aircon, TT comps, blue dash lights & switches, Koni TA/Nothelle springs, OBD2, 264 cams, Schrick

    my car

  7. #7
    CF Nutter fendervg's Avatar
    Join Date
    13th June 2009
    Location
    Dublin, IE
    Posts
    2,110
    Quote Originally Posted by fla View Post
    Well the fuel filter change has made a big difference - no sluggish starting and so far no popping noises again!
    Got the wrong size from Bosch which according to their part numbers was correct. Returned it and bought one from GSF (Mann) fits perfectly.

    Used some silicone grease on the clips.

    Longest part was locating the trolley jack in the right place whilst having space for the stand AND having clear access.
    Good to hear - hopefully that will have sorted it.

    I'm always nervous using the jack and worried about crushing some part. For the reat I lift under the beam at the centre and then use axle stands both sides.
    ____________
    fendervg

    93 Corrado VR6
    Members Gallery

Similar Threads

  1. Replies: 6
    Last Post: 30th May 2015, 6:18 PM
  2. Replies: 10
    Last Post: 20th September 2012, 3:37 PM
  3. Fuel pump noise and smell
    By livi1982 in forum Engine Bay
    Replies: 1
    Last Post: 22nd June 2007, 4:33 PM
  4. Corrado 16v fuel pump and Golf Mk2 16v fuel pump....
    By alackofspeed2 in forum Engine Bay
    Replies: 4
    Last Post: 21st March 2006, 6:15 PM
  5. Fuel pump noise??
    By Matt in forum Engine Bay
    Replies: 3
    Last Post: 24th August 2003, 11:01 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
We are the world's largest community for VW's Super Coupé! Be it 8v, 16v, G60 or VR6 (or maybe something else!), everybody's welcome! If this is your first visit, be sure to click register and fill out your details before you can post.
Help us
This site is run on donations.
Please help keep the forum alive!
Follow us
advertising & sponsorship
Are you a company looking for advertising that could benefits our users? For site & forum sponsorship, please see our dedicated microsite here.