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Author Topic: mk2 digifant gti - which wire is it?  (Read 2875 times)

Offline tsr_adi

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mk2 digifant gti - which wire is it?
« on: 11 January 2011, 14:58 »
Had to make an adjustment to the brake light switch. After fixing that I now have another problem. Its back to its old tricks and I have no spark and no fuel pump prime. Now whenever this happened before I wiggled the wires at the back of the ignition switch and it would work. Now nothing will persuade it to work.

I'm pretty sure the 20 odd year old wiring is at fault and I must have a broken wire somewhere in that region. And it must be an ECU power feed from the ignition switch. Now can anyone tell me which wire it is from the ignition switch that sends power to the ECU? When I know exactly which one it is, I'l have to keep probing it with a continuity tester until I find where the break is. Theres a kink in a black/yellow wire that goes into the ignition switch so thats my prime suspect at the moment, I'm hoping someone can confirm this is the live feed for the ECU  :smiley:
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Offline rubjonny

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Re: mk2 digifant gti - which wire is it?
« Reply #1 on: 11 January 2011, 15:53 »
its the black wire you want to look at, but if the dash warning lights are coming on its nothing to do with thye ignition switch or wiring, its either the ecu relay or the wiring between the rear of the fusebox and the ecu

oh and black/yellow wire is the x-over feed for the lights, wipers, blower etc. nothing to do with tyhe ecu.

although saying that if car has been bodged or if there is an aftyermarket immobiliser that could be the reason dash works but not ecu, look for dodgy splices to black and black/yel wire
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #2 on: 11 January 2011, 16:36 »
i was really hoping it had somethin to do with the wiring behind the switch, as whenever its done this before ive wiggled the wires at the switch and its worked, plus the yellow and black one is kinked. Just seems like a co-incidence to me. Need to get me a multimeter to check continuity on them...
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #3 on: 11 January 2011, 17:13 »
Thinking about it the interior loom did have an immobiliser fitted, but when I took it out of the donor car I removed it all, so I guess where it was spliced in, the wires could have broken. That would mean removing the dashboard again and checking all the loom going to the fusebox  :sad: :undecided:
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Offline rubjonny

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Re: mk2 digifant gti - which wire is it?
« Reply #4 on: 12 January 2011, 10:05 »
can check it with dash in, just take out the lower trays and drop the fusebox off its hanger. follow the ign switch wires down and you'll soon see if any have come apart!  you did fit an ecu relay right? if so make sure you can hear/feel it click when the ignition is switched on. look for a green 2 pin plug at the back of the fusebox, plug R. this supplies power to and from the ecu relay :)

also read this, CE1 pre-90 MK2 bits, fusebox front pic on page 2, rear pic on page 4
http://www.golfgtiforum.co.uk/index.php?topic=44637.0
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #5 on: 12 January 2011, 11:48 »
cheers for that, relay does click when i turn ign on. Jus checked continuity where the old immobiliser was spliced in and thats ok, also got power out of ign switch. Il check the green plug now...
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #6 on: 12 January 2011, 11:57 »
Right with the ignition on theres power at the black wire but not the black/yellow wire at the back of the green plug. Does this mean theres a break in the black/yellow wire between the green plug and the ecu?
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #7 on: 12 January 2011, 11:58 »
wait, that didnt make sense... OK I have no idea why the relay is clicking but theres no power at the black/yellow wire at the back of the green plug...
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Offline rubjonny

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Re: mk2 digifant gti - which wire is it?
« Reply #8 on: 12 January 2011, 12:48 »
black/yel is the power output from the relay, so if there is no power there when the plug is fitted to the fusebox then we have found the problem! if you were checking it with the plug disconnected then that would explain it ;)

the ecu relay should be a #53 relay in slot 1, try swapping it with one of the other 53 relays on your fusebox :)
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Offline tsr_adi

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Re: mk2 digifant gti - which wire is it?
« Reply #9 on: 12 January 2011, 15:15 »
i was checking the power with the plug connected, and the relay was clicking, but with no power coming out i guessed it must just be a faulty relay that works when it feels like it. Swapped it with another 53. And it works. All before i read this! Cant believe my golf was off the road for so long because of this!
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