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Thread: Fuel pump issues on 84 8v Gti

  1. #1
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    Fuel pump issues on 84 8v Gti

    Hello everyone was hoping for someone with more knowledge than me can help me out with my project. Its a 1984 GTi 8v with K-jet and the fuel pumps will not prime or run so I'm not getting any fuel to the metering head on the air box. I have replaced the intank pump and the fuel pump relay also but I'm still not getting anything at all.

    I have just bought a power probe and tested the wires going to the in tank pump and on all three wires the probe is lighting up with the negative light I'm still learning how to use the probe so not sure if I'm doing anything wrong, I had the same thing on the pump under the car both came back with the negative light and the positive one didn't light up, was hoping some one can help me out with maybe a wiring diagram for the fuel pumps and what I should test next with the probe and what sort of readings I should get back. I have used the probe on the relay pins on the fuse box and got a good reading from what I know, I'm pretty good with the oily bits but electrical work frustrates me no end so any help with much appreciated

    Sorry for rambling on thanks in advance
    1984 Golf GTI 1.8 8v

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    Administrator Crasher's Avatar
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    The fuel pump relay is at position 2 on the main section of the fuse box, top row second from the left. Take this out and look at the two large contracts, these are 30 and 87 (can’t remember the box position number off the top of my head, 2 & 4?). Make a bridge between the two large slots on the relay plate and the fuel pumps must run. If the do but the relay isn’t closing when it should, check the red/black wire on the coil at position 1 is connected, it is in a two pin hosing with a green which is the trigger from the ignition amp which provides the pulse to trigger the fuel pump relay and send an RPM signal to the instruments.
    "I disapprove of what you say, but I will defend to the death your right to say it"

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    Quote Originally Posted by Crasher View Post
    The fuel pump relay is at position 2 on the main section of the fuse box, top row second from the left. Take this out and look at the two large contracts, these are 30 and 87 (can’t remember the box position number off the top of my head, 2 & 4?). Make a bridge between the two large slots on the relay plate and the fuel pumps must run. If the do but the relay isn’t closing when it should, check the red/black wire on the coil at position 1 is connected, it is in a two pin hosing with a green which is the trigger from the ignition amp which provides the pulse to trigger the fuel pump relay and send an RPM signal to the instruments.
    I have bridged the 2 pins and didnt hear a thing from the pumps, I also checked the red and black wire with power probe and it wasnt broken and the connector was tight on the coil and didnt look corroded. I'm also getting a spark from all plugs so it makes me think that the coil and hall sender is working correctly, its really got me scratching my head

    thanks for the reply
    1984 Golf GTI 1.8 8v

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    Administrator Crasher's Avatar
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    Stupid question but you have checked fuse 15 haven't you? The power to socket 2 is shared with many other systems but check that there is power there.
    "I disapprove of what you say, but I will defend to the death your right to say it"

    Evelyn Beatrice Hall (28 September 1868 – 13 April 1956)

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    Quote Originally Posted by Crasher View Post
    Stupid question but you have checked fuse 15 haven't you? The power to socket 2 is shared with many other systems but check that there is power there.
    Yes I have checked all fuses and they are all good, I think it might have something to do with the old toad alarm that is on the car but I thought that bridging the relay pins would over ride that
    1984 Golf GTI 1.8 8v

  6. #6
    Administrator Crasher's Avatar
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    Ahh, no bridging the relay won't bypass an immobiliser circuit if the system is installed to Thatcham standards. Drop the fuse box down, find the black plug in the centre of the board and follow the yellow/red wire from position 14 (there is a red/white from there as well for the Auxiliary air valve) and as you follow it along to the harness tube you should find an intercept... That is unless the fitter was a devious ******* like me and intercepted the feed along the sill. As an aside, doing this used to cause terrible problems with hot starting on the G60 models as they had an after run function to keep the fuel cool, you had to interrupt the relay trigger on those which isn't as secure.
    "I disapprove of what you say, but I will defend to the death your right to say it"

    Evelyn Beatrice Hall (28 September 1868 – 13 April 1956)

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