DiDueColpi Fred Key West coast - Canada (1375 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Coil wiring
If that wire had a dead short then it has very likely blown a fuse. I'm assuming it's fused, but not positive as it's non stock wiring.
As a WAG I would suspect that it goes to the I terminal on the starter. This provides full power to the coil when cranking. Cheers Fred |
Re: Coil wiring
Thanks for the response Fred. That makes perfect sense. As a matter of fact its one of the first things I thought about - especially noting the flat terminal end on the wire. Two things ended up having me rule that out however.
(1) the starter is situated too far down below for this wire to reach. Stretching it I got it down to within about 3 inches of the starter. (2) The wire would have had to defy gravity - fallen upward - in order to land on the exhaust manifold. This failure happened right at dusk on Saturday evening. I was trying to get it figured out before Monday afternoon when I had an appointment with the mechanic to install some front end parts that had recently come in from England. Since I didn't get it sorted, I towed the car to the shop yesterday. As soon as I'm able to talk to the shop I'll post the solution on here. Tim |
DiDueColpi Fred Key West coast - Canada (1375 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Coil wiring
The only other possibility that comes to mind would be power for the choke heater.
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Re: Coil wiring
Thanks again Fred.
Regardless, it seems to me you're right about the ignition circuit side of the fusebox being blown. I should know more tomorrow. Tim |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6496 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Coil wiring
That erosion on the corner of the spade connector indicates a strong chance that it was arcing before the fuse blew.
Jim |
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Re: Coil wiring
Fred,
The car repairs are not yet finished - the front end parts are installed and it is now at the alignment shop. I did speak to my mechanic today however and got a partial answer. You were not wrong Fred. There was a blown fuse on the ignition circuit somewhere. They replaced the fuse and left the loose wire unconnected. The car started and ran fine. When it gets back from alignment tomorrow they will track down the attachment point. The cooling fan is a later add-on - and has nothing to do with starting/running, so I'm suspecting it might be the culprit. Will know when I pick it up! Tim |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6496 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Coil wiring
Tim, that spade terminal is made of sterner stuff than solder, that corner was not melted off. If it had been it would be a blob at that point and not the jagged missing edge that you see there. You MIGHT get that from long term rubbing against a hot and rough surface like a cast iron manifold but it is much more likely to have gotten that way from electrical discharge, sort of like you might see in an EDM machine only without benefit of the oil. That's why I say it was eroded. Being a loose electrical wire that is the most likely and since you say there was a blown fuse, even more likely. Probably the car was running with that wire in light contact with the header, and it occasionally arced across depending on movement from vibration, each arc taking out a little metal until it got the way it is and at some point making contact long enough to blow the fuse and stop the car.
Jim |
Re: Coil wiring
You guys may be correct!
The final opinion is that this is truly a mystery wire! Seriously, the mechanics never found where it was supposed to have been attached. Consensus is that it was not attached anywhere on the other end - just lying up in there and eventually vibrated its way free, shorting on the manifold and blowing a fuse. Everything works. Even the addons - fuel pump, cooling, fan, radio. Don't ask me why the terminal end was still connected to the coil! The wiring in general, but especially under the dash and fusebox, is a total mess. Apparently when the engine swap was done years ago, they didn't replace the old fusebox, they added a second one! Wires are going everywhere - jumping from one to the other, etc... It was highly recommended that we go ahead with new wiring. I agreed to it. The new wiring harness was placed on order today and should be ready in 5-6 weeks. I knew this was coming but wasn't thinking I would do it this quickly. What I wanted to do is replace the dashboard, center panel, glovebox, and trim, etc... at the same time we did the new wiring. The only dashboard replacement options I've seen (ahspares & moss) are the woodgrain. Does anyone know if there are any other options out there? Maybe somebody does custom work in this area? Thanks again for all the responses, Tim |