M-Tdi conversion,starter solenoid +12V electrical issue [Solved]

[ALIKA T3]

Happy New year to you all!

For those of you who know me, I've been working on my Syncro & conversion project for 10 years and have finally started the engine. ( 1985 2WD Van)
Plenty updates due but I will sit down when it finally runs to catch up with that as I decided to not spend so much time posting and more wrenching for completion for my 40th birthday coming very soon.

I have an issue with the starter solenoid wire ( ignition).

I installed a load relay kit in the engine bay ( kinda irrelevant but read on).

If I start the van with the key, 2 seconds after running, the solenoid engages again and makes the starter grind teeth!!

I unplugged the ignition switch and used another one: same issue.

I unplugged and left unplugged the ignition switch connector.

I applied 12vdc directly from the battery in the engine bay to the injection pump fuel shut off ( also a solenoid), unplugged the Vanagon factory starter solenoid wire and applied a temporary 12v to the starter relay to start the van.
While the engine is running, the factory wire has alternator voltage coming out of it!
How is it possible? It's unplugged from the ignition switch??
If I unplug the alternator blue wire while running, voltage drops to battery voltage.

I'm lost at where to look next as I did not modify any portion of this ignition switch starter solenoid wire :/

I feel like there's a relay interference somewhere, sometimes it doesn't not stay hot but most of the time it does.

I see another black/red wire under the same connector at the ignition switch.

I installed headlight relays and upgraded to a 1986 3 speed fan with complete attached factory wiring. There must be something in there causing this issue :/

Thanks for your help!

I feel like it's track 78 on this diagram that's causing this or track 15.

_________________
Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget

[crazyvwvanman]

It is normal for the start 50 wire to still have voltage on it even after the engine is running. That voltage comes from optional relays such as a fridge relay or aux battery relay. These 2 relays often use the alternator blue wire to trigger them and VW decided to use the starter 50 circuit as the relay ground. So there is always a small current flowing through the starter 50 in vans with these relays in their stock setup. The starter motor solenoid coil takes way more current than this tiny amount and so it works as the ground for the relays but when you put in a small starter relay like you did that tiny amount of current is enough to activate the small relay. So once the alternator warning light turns off the added small relay is triggered and that runs the starter when it SHOULD NOT.

The solution is to move the fridge relay ground or aux relay ground from the starter 50 circuit to actual body metal. This is a known issue when adding a starter relay.

Mark

[ALIKA T3]

Mark, you're a genius!

I just came back to post as I tracked down this freaking wire from behind the dash while unplugging and doing testings with engine running.

It goes under the carpet and under the driver's seat. When I saw the relay, I was, oh, yeah, I read that a long time ago....and now you're calling it.

That's what happens when you work on and off on something for years... I just started to leave tape now with a written note everywhere something is half done bc there's too much to remember and then you can't sleep at night 🤣🤣
That would have been helpful here, on of the little details that needed to be done.

Have a good day and thanks again for taking the time to read my novel.

Aloha 🤙
_________________
Silicone Steering Boots and 930 Cv boots for sale in the classifieds.
Syncro transmission upgrade parts in the Classifieds.
Subaru EJ22+UN1 5 speed transmission
http://www.thesamba.com/vw/forum/viewtopic.php?t=416343
Syncro http://www.thesamba.com/vw/forum/viewtopic.php?t=4...num+gadget