Fuel delivery problem- Fuel pump wiring query?
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Thread: Fuel delivery problem- Fuel pump wiring query?

  1. #1
    FRESHMAN ROVER rudseyrover's Avatar
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    Fuel delivery problem- Fuel pump wiring query?

    My RRC has been off the road for the summer, I have been trying to give it a run every few weeks or so and it always started fine.

    I have let things slip and left it for three months and tried to start it, whilst it was cranking ok it would n't fire. The fuel gauge stopped working many years ago so to be on the safe side I put c.7 litres of fuel in. It still would n't crank.

    I disconnected the fuel line from the rail and no fuel is coming through.

    I checked the C4 fuse and swapped the relays round without success.

    I checked the inertia switch under the seat and reset up and back down

    I accessed the top of the fuel pump through the boot floor, my haynes manual is very vague on its description of the later fuel pump so not clear what wires do what. I disconnected the three pin multi plug and checked voltage with the ignition key in postion two, there was only 5v showing. Are these wires for the pump or the fuel gauge? I understand the pump only primes for a small period of time. Is there any other way of testing it in situ?

    The battery is low in power due to failed cranking so I have it on charge. It was enough to crank it however.

    Any help appreciated.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

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  3. #2
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    I am still trying to sort this problem.

    On the passenger side rear wheel arch there are wires that seem to run from the top of the tank and along the side of the chassis. Is this the feed back to the ECU. There is another connecter here, is this the main power feed to the pump?

    My Haynes manual is very unclear on hire the pump is connected on these later models.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  4. #3
    SITE ADMINISTRATOR RRToadHall's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    have you tried downloading RAVE? Chances are the RAVE you find on the internet will be for a 95, but may well provide a better insite over Haynes.
    Sucking at something is the first step to becoming sorta good at something.

  5. #4
    SOPHOMORE ROVER
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Quote Originally Posted by rudseyrover
    I am still trying to sort this problem.

    On the passenger side rear wheel arch there are wires that seem to run from the top of the tank and along the side of the chassis. Is this the feed back to the ECU. There is another connecter here, is this the main power feed to the pump?

    My Haynes manual is very unclear on hire the pump is connected on these later models.
    There should be 2 pairs of wires. One pair supplies power to the pump, the other is for the level sensor. They should get bundled together at the point they are clamped to the chassis.

    Sounds like your pump is dead, check if you have voltage at the top of the fuel pump, if so sounds like time for a replacement.
    1989 RRC
    2001 RR HSE

  6. #5
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    I have taken the pump out and bench tested. Its seems to be working ok.

    I have now caused another problem, the fuel lines were corroded and I have threaded (by removing) the union connecting the pipe to the pump. The pipe has the brass union, then a section of rubber then is connected to a metal fuel line. Can any one suggest a way round other than repalcing this complete section of pipe?
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  7. #6
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    I am still trying to resolve the issue with fuel supply.

    Using a spare battery I have hard wired it through the access panel in the boot area. The pump works, the engine starts and runs ok. it was great to hear it running again.

    Whislt the engine was running (with bypass power) I used a multi meter to test the fuel pump supply in the black plastic socket and it was fluctuating around 11-12v. But when I disconnected the spare battery and tested iginition on it was barely registering any feed.

    I have tested the C4 fuse socket with my multi meter and that's showing 12v suggesting there is the correct signal getting to the fuse box but between there and the pump there is a problem.

    when the engine is running it is giving the correct power supply to the pump its not when the engine is off and the ignition turned on. I have used the spare battery to prime the fuel line and try starting it that way but it wont start that way.

    Does anybody have any ideas??
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  8. #7
    FRESHMAN ROVER
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Relay? Wiring? The relay is under the right-hand seat. In the RAVE under FUEL SYSTEM -> ELECTRONIC FUEL INJECTION RELAYS.

    "Access to the relays is gained through the opening at the bottom of the seat when the seat is fully forward.

    1. Fuel pump relay (blue base)." It is pictured as being to the left of the "Main relay (black base)". If I remember correctly mine was the other way around so I just replaced the relay on the blue base.

    If the relay is fine then maybe check the wiring? I have a friend whose car sat a long time, and he had fuel pump issues. Turned out that mice (or something) had chewed through some of the wiring. Good luck.
    1993 LWB 4.2 V8

  9. #8
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Thanks

    I will have another check of the relays.

    I can get near enough 12v from the fuel pump wire when the engine is running but not when the ignition is on but the engine not running

    its as if the when the igintion is turned its not telling the fuel pump to engage but when the pump is hot wired and started it then tells it to work.

    I have 12 v at the fuse box when the ignition is on, somewhere from there to the pump I have a problem. Looking at the wiring diagrams there is only the inertia switch between the fuse and the pump. So thats tomorrows job to bypass it.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  10. #9
    FRESHMAN ROVER
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Yes that is indeed strange, sorry, I missed that you already swapped the relay out. The good signal you get when its running could also rule out chewed up wiring... So back to the drawing board.
    1993 LWB 4.2 V8

  11. #10
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    I did nt bother trying to bypass the switch in the end. It looked quite difficult to access and with the engine running I am getting the correct voltage which would imply thats ok too.

    There is a connection problem with the connector onto the pump itself. Even when hot wired it sometimes does nt connect, will after some wiggling, I can't see any obvious problem with it but I may replace that part.

    An old landy mechanic (more experienced on Series 2/3s/pre-efi RRCs) friend has suggested creating a new connection from the back of the fuse box to the pump.

    That maybe my next route.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  12. #11
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    I never managed to fix this problem as I need the car on the road!

    I have decided to have another go and this time I won't let it beat me.

    I am going to buy new relays this week.

    I have a couple of questions:

    what are the symptoms of duff relays, would the car still run with the bypass battery?

    Where is the best place to get the relays, presumably they are generic Bosch items, the seam expensive on the usual LR websites.

    Any help appreciated.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  13. #12
    FRESHMAN ROVER rudseyrover's Avatar
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    Fuel pump power supply problem

    I sourced Bosch relays from Eurocar parts for alot less than LR were quoting.

    I have now replaced the relays but still it won't start, I hear them click when I turn the ignition on. I am really struggling to get my head round this one.

    If I power the pump from a seperate battery it will start and run fine. I will also get a 12-13.5v feed from the black circular socket when the engine is running. I have no assistant to allow me to check whether I get the brief feed of power when the ignition is turned on I assuming its not, ie when I go to crank the car the pump does nt get any power.

    The fact I get 12-13.5v when running makes me think the collision isolater switch is ok.

    I have created a new earth connection from somewhere else on the car and connected it to the fuel pump, to elimante a poor earth for the pump. Again the engine fails to start.

    Any more suggestions??
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  14. #13
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Latest update.

    I have re-connected the black cylindrical three pin sockets at the top of the pump. I have spliced a feed into the blue/white wire to my second battery between the actual pump and the black cylindrical socket.

    I had antcipated that once the engine was running, the pump would run with power taken from the main feed and I could disconnect the second battery supply from the spliced connection. However, when I set this all up and disconnected the second source of power it stalled again. I really don't see why it would n't run as when disconnected there is sufficent power getting through to the socket. I am going to replace the wiring harness from the socket to the pump but am struggling to see how it could be an issue with such a short simple section of wiring.

    I am planning now to create a new feed as a short term fix from the cigar lighter to the pump as I feel I am exhausting options.

    The niggling concern now is whether its the ECU or the unlikely situation that my new relays are faulty.
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  15. #14
    FRESHMAN ROVER rudseyrover's Avatar
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Good news its up and running

    I have been in the garage in the dark, with my torch and scratching my head.

    I took the relays out and back in again.
    Double checked all the fuses, all ok.
    Split and reconnected the connector socket under the left hand wheel arch.
    I rigged my multimeter to the top socket on the pump and turned the ignition on and tried to run back to see if I had a signal. Nothing.
    I tried to push the tip of the multimeter needle into the power supply brass pin in the socket, and it made it wider.
    I gave up and re attached it to the female socket and went to turn the ignition on again, the abs noise stopped and I heard the faint whirr of the pump and it shut off as its meant to.
    I turned the key and it fired!
    I was getting 12v at the spliced wire, no need to use a second battery.

    So its running after six months and several hours in the garage and trawling the forums.

    All I need to do now is get it MOT'd, then I am back on the road! If I could only fix the $12 a gallon fuel prices I would use it every day!
    2004 Range Rover 3.0TD6 HSE 108k miles
    1996 Range Rover 4.0SE 196k miles NOW SOLD
    1993 Range Rover Vogue 3.9i V8 159k miles NOW SOLD
    2003 Porsche 996 Turbo 43k miles
    1990 Mercedes 300CE 114k miles
    2012 Fiat 500 Twin Air 0.9 turbo 3k miles

  16. #15
    SOPHOMORE ROVER
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    Re: Fuel delivery problem- Fuel pump wiring query?

    Sounds like something is loose back there around that connector. If you think making the pin wider has solved the problem, then good.

    If it were me, I'd replace the dodgy section, or I'd be always wondering if the connection was going to break again....
    1989 RRC
    2001 RR HSE

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