Right so I finally got round to fitting the Mk3 starter motor to 2y gearbox, wired up like so (thanks saladman for the pic): Only difference is I only have one black wire. I turned the key and this thing fairly cranks starting the engine in no time and confirming the old one was knackered. So I sat there nursing the carbs til it would idle when I notice smoke from the dash area. When I start the car again something in the fusebox is glowing hot and smoking. It didn’t do this with the old starter so have I wired it up wrong? Is it something to do with having only one black wire to the newer starter? Haven’t had a chance to get the fusebox off and have a look at the evidence, the fuse box is original ‘79 Scirocco bullet type. Please help electrics are not my thing!
What is the black wire for? Where was it in the old starter? Is it bolted to the "solenoid stud"? Which I doubt it should be.
Just checked the old starter and there looks to be a very faint negative symbol next to the black wire terminal
I’m sorry that happened to you. Be cautious! I’d disconnect the battery, remove the trim at the fuse box and lower the fuse box then have a good look at ALL the wiring in that area. Then you’ll be able to see which wires shorted and are burnt and then by understanding the effected area of the loom will be better placed to find the origin of the short. You’ll have to check all that anyway moving forward. I did something similar once replacing the dash illumination bulb on my headlight switch. The shorted wires after burning their own insulation off start to melt insulation on adjacent wires they’re touching and the wiring is really packed in around the fuse box area. The good news is all the harnesses to the fuse box are just plug and play, or can replace individual wires by sourcing correct colour wire and crimp connections from eBay.
I’m hoping to get in the garage later and see just what damage has been done, hopefully not too much. I wonder if as Tristan suggested the black wire shouldn’t be connected to the solenoid stud, not sure where else it could go?
If it's an earth, and now it's connected to the solenoid lower, it becomes live while the engine is cranking. Which would cause major issues.
On second inspection the marking on the starter was just a bit of dirt that looked incredibly like a negative symbol. How do I find out what the black wire does?
It was originally a 1600 on kjet now on twin45/dta ignition. Who knows what I have fried, fairly furious with myself!
Thats what I thought from reading threads on here, so I thought it was ok to wire it to the solenoid stud
If it's the lower solenoid stud, there'd never be anything else attached to that. It sounds like it's something you don't need ?
I’m no expert but if it is the cold trigger then you could well be right and it’s not used in the current setup. It is attached to the lower stud as per this thread: https://clubgti.com/forums/index.php?threads/16v-mk2-running-woes.292068/
The cold start injector circuit (or 5th injector on a 16v kjet as it’s sometimes called) earths through the thermotime sensor and gets its live from either the starter solenoid for cold cranking or a vacuum switch for full throttle enrichment. As far as I can remember that black wire should be a live. But, question is if the cold start circuit has been removed on yours then where does that black wire go to on your current setup? As I said, that is a working theory from memory so pease get it confirmed, would hate mis-info to cause you anymore agro. I’ll check the black wire on mine tomorrow if I get the chance. I know you’re going to be pissed off but dont beat yourself up too much. We’ve all done it or something very similar. Unfortunately most of us aren’t professionals and while self teaching and learning on the job is going to throw up some mistakes.
Thank you for the advice and understanding of my frustrations. I have some knowledge and experience of the mechanical side but electrics always feels like a dark art. I have owned this car for 16 years, bought it from its first owner as a standard Storm and slowly changed it year on year. Some of the work has been completed by me and some by trusted third parties so unfortunately there are some holes in my knowledge particularly around going to carbs/dta. The original engine and I assume current wiring (or majority) is 1600 8v 1979, would this have had csi?
I think the only K-jet Mk2 to have the Cold Start Injector was the 16v (engine codes KR and PL, PL is the US spec 16v). Early 8v’s (like yours) relied on an Auxiliary Air Valve and the WUR for cold start. So don’t know why yours had this wired up on the previous starter motor and why it wouldn’t have caused this same issue then, cos from what I can see you’ve wired up the new starter the same way as the old one. I’m going to check mine shortly and get back to you then. Think you need to find out where your black wire is going to?
So on mine I have two black wires. One goes to the Cold Start Inj and the other goes to the vacuum switch for full throttle enrichment. Black wire is switched live, therefore normally earth but switched live while cranking only. But this is 16v don’t forget.
