12 replies to this topic

[Mood 1990]

I broke down on Sunday evening on the return leg of a trip from London to Leeds. Having not long gone over the dartford crossing I lost acceleration and then the engine died.

 

I pulled over to the hard shoulder, popped the bonnet to find the positive wire from the coil melted all the way back round to the fuse box. This was a brand new loom, attached to a brand new fuse box, all fitted during the restoration of my mini this year. Ive had the car back for 3 weeks before melting the wire.

Has anyone got some possible scenarios which could have caused this wire to melt?

 

Its started life as a 998 1985 mini city e, now a 1275 with an inertia starter motor.
 

 

My initial thoughts were a faulty wiring loom, perhaps some wires with cracked insulation shorting out on each other?

 

Or can a faulty coil pull too much power through a wire to cause it to melt?


Any ideas greatly received?

 

[Mood 1990]

I forgot to say I've read about the resistive white pink wire melting but this wire appears to be solid white, unless somehow all of the pink has melted away leaving only white visible.

[Wise Old Elf]

I have had this. I had a short in the fusebox.

I was stuck at the side of the road so cleaned up the terminals, cut a piece of square plastic from an ice cream tub and screwed this between the fusebox and bulkhead.

[Gremlin]

To determine whetther it is a white wire or a burnt pink and white wire, look for a yellow and white wire going from the starter motor to the positive side of the coil (same pin as melted wire)

[Dan]

What coil is fitted?

[dklawson]

I had the same thought as Dan.  Have you measured the coil resistance across the low-tension terminals with the wires removed?

[Mood 1990]

Wise old elf; So it was shorting from the fusebox onto the bulkhead? the fuse box is brand new and the engine bay was painted too so hopefully its not shorting out. Is there a way to test for a short in the fuse box?

 

Gremlin; if there is a yellow and white wire does that mean it was a pink and white or just the white it looks like?

Dan and DK; Pretty sure it is a 12v non ballast coil as I'm running an electric module in my dizzy cap. (has been in there about 2 and a half years with the old loom). But i can get the multimeter out tomorrow, unfortunately i don't have the luxury of a garage and its pissing it down.

[Gremlin]

If it has a white and yellow wire it should have had a pink and white, if this is the case it should also have a ballast coil

[Mood 1990]

just braved the rain to quickly check and it looks like the suspected white wire is the only wire going to the positive side of the coil.

[Gremlin]

Then as others have said check the fusebox for obvious problems, also look at the back if the ignition key for any signs of heat/burning

[Wise Old Elf]

Wise old elf; So it was shorting from the fusebox onto the bulkhead? the fuse box is brand new and the engine bay was painted too so hopefully its not shorting out. Is there a way to test for a short in the fuse box?

 

Gremlin; if there is a yellow and white wire does that mean it was a pink and white or just the white it looks like?

Dan and DK; Pretty sure it is a 12v non ballast coil as I'm running an electric module in my dizzy cap. (has been in there about 2 and a half years with the old loom). But i can get the multimeter out tomorrow, unfortunately i don't have the luxury of a garage and its pissing it down.

 

The contact on the fuse box was dirty so it shorted to the bulkhead. Current will find the easiest route so will jump a gap if the contact is dirty.

An ammeter between the coil contact and the wire will show it up.

[Mood 1990]

Cheers i will double check it, hopefully that won't be the issue as its only a 3 week old fusebox!

[KernowCooper]

Can you test the ohms between the coils + and - terminals with the cables off and post back your readings.