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id
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Joined: February 16, 2008
Posts: 79
Location: Victoria, BC
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 Posted: Tue Apr 15, 2025 8:31 am Post subject: Ignition coil ground connection (Solved) |
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My 86 Westy turns over, and won't start. No spark coming out of the coil. Relays weren't clicking so replaced them. Still turns over won't start. No battery voltage at the coil. Replaced the ignition switch. Still no battery voltage at the coil. Noticed one of the ground wires to the coil had come loose. Can't figure out how to open the plastic housing to reconnect the wire.
Anyone done this before?
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'Green Dragon' 1986 Westy GL |
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crazyvwvanman
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Joined: January 28, 2008
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| Posted: Tue Apr 15, 2025 8:54 am Post subject: Re: Ignition coil ground connection |
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Those are not ground wires.
The fatter green wire is from the ECU, to fire the coil, required.
The thinner green wire feeds a tach signal forward to the dash.
This tach signal connection isn't required for the engine to run.
Mark |
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MarkWard
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| Posted: Tue Apr 15, 2025 11:23 am Post subject: Re: Ignition coil ground connection |
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| What coil is that? |
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id
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Joined: February 16, 2008
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Location: Victoria, BC
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| Posted: Tue Apr 15, 2025 7:54 pm Post subject: Re: Ignition coil ground connection |
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Thank you for the information Mark!
Clearly the problem lays elsewhere.
And for Mark Ward…
This is the ignition coil my local VW repair shop installed when I was having issues previously
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crazyvwvanman
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Joined: January 28, 2008
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| Posted: Tue Apr 15, 2025 11:30 pm Post subject: Re: Ignition coil ground connection |
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The left relay provides power to the ECU.
If it doesn't click on each time with the key on then no hope of starting.
The early 86 model year wiring can be a problem in this area so it is important to know which version you have.
About serial number 055,000 is when the wiring changed.
What are the last six digits of your vin#?
Mark |
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Wildthings
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| Posted: Wed Apr 16, 2025 3:19 am Post subject: Re: Ignition coil ground connection |
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You can buy release tools to get the terminal to come out of the insulator and new terminals are available on line. I usually just end up finding an appropriately sized brad or solid steel wire and beat it flat on some sort of anvil to make a release tool. You could also just saw the insulator in two and use the part for the green wire running to the ECU, toss the rest and just use a fully insulated female spade terminal for the tach wire. I agree your broken wire isn't what is keeping it from starting.
Not having power to the #15 terminal on the coil could well be your ignition switch has failed. If the switch proves to be bad, try and find an OEM VW switch as they are superior to aftermarket and typically cost less. Buy two while you are at it and keep the second one as a spare in your glove box. |
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MarkWard
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| Posted: Wed Apr 16, 2025 4:44 am Post subject: Re: Ignition coil ground connection |
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The ignition coil is specific to the VW Digifant fuel injection. Unlike earlier ignition systems, the engine ECU has the “drivers” to fire the coil. This is likely not your problem, but an improper coil could damage the ECU.
It’s also interesting that a shop replaced the coil for a “previous” problem and managed to not get it plugged in correctly. What was the original problem that required the coil? I’m assuming a spark issue? Could the problem your having now be related to the original problem? |
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id
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Joined: February 16, 2008
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Location: Victoria, BC
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| Posted: Thu Apr 17, 2025 5:58 am Post subject: Re: Ignition coil ground connection |
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| crazyvwvanman wrote: |
The left relay provides power to the ECU.
If it doesn't click on each time with the key on then no hope of starting.
The early 86 model year wiring can be a problem in this area so it is important to know which version you have.
About serial number 055,000 is when the wiring changed.
What are the last six digits of your vin#?
Mark |
Hey Mark, thanks for this. Last six digits are 057963. The left relay certainly does not click…
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id
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| Posted: Thu Apr 17, 2025 6:02 am Post subject: Re: Ignition coil ground connection |
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| MarkWard wrote: |
The ignition coil is specific to the VW Digifant fuel injection. Unlike earlier ignition systems, the engine ECU has the “drivers” to fire the coil. This is likely not your problem, but an improper coil could damage the ECU.
It’s also interesting that a shop replaced the coil for a “previous” problem and managed to not get it plugged in correctly. What was the original problem that required the coil? I’m assuming a spark issue? Could the problem your having now be related to the original problem? |
The previous problem was the same. Engine would turn over and not fire. So yes. No spark. With the new coil in it worked fine for some time. Had it running on the driveway this winter just to turn the engine over. Brought it back into my garage and the next morning it would turn over but not start. Been trouble shooting since.
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id
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| Posted: Thu Apr 17, 2025 6:05 am Post subject: Re: Ignition coil ground connection |
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| Wildthings wrote: |
You can buy release tools to get the terminal to come out of the insulator and new terminals are available on line. I usually just end up finding an appropriately sized brad or solid steel wire and beat it flat on some sort of anvil to make a release tool. You could also just saw the insulator in two and use the part for the green wire running to the ECU, toss the rest and just use a fully insulated female spade terminal for the tach wire. I agree your broken wire isn't what is keeping it from starting.
Not having power to the #15 terminal on the coil could well be your ignition switch has failed. If the switch proves to be bad, try and find an OEM VW switch as they are superior to aftermarket and typically cost less. Buy two while you are at it and keep the second one as a spare in your glove box. |
Thanks for this. I did replace the switch, didn’t solve the problem 
Will see if I can Jerry rig a release tool and fix the tach wire. Thanks for the tip!
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crazyvwvanman
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| Posted: Thu Apr 17, 2025 9:26 am Post subject: Re: Ignition coil ground connection |
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There is a known problem with a certain pin in the dash fuse/relay panel.
This Pin D15 carries power from the key switch to the ignition coil.
The pin cooks over time and becomes intermittent or fails entirely.
Search this forum for D15 to see more including photos.
Mark |
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crazyvwvanman
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id
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| Posted: Sat Apr 26, 2025 7:12 am Post subject: Re: Ignition coil ground connection |
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Thanks for this tip Mark. Was indeed a D15 pin that was burned. Swapped it to D23 and we are back up and running. (With fresh relays and an ignition switch along the way). Still need to go fix the tach connection…
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