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MG Midget and Sprite Technical - Wiring loom just caught fire

Hey all

After some help if poss

Just completed a service on my 73 midget after new engine running in -

Changed All oils - checked valve clearances etc - lovely jubly

Started the car after checking clearances and started very very lumpy - then smoke from under dash

Immediately turned off ignition checked under dash and found the rear part of the loom had completely split open and white wire melted through
I believe this was fuel pump wire

Was a brand new loom from auto sparks who provide looms to all the big dealers so I know not a cheap loom

I'm thinking may have burnt as it has earthed somewhere - maybe rubbed through on bodywork -

Anyone got any ideas or suggestions / I don't want to put a new loom in for it to happen again

Thanks
richard weaver

Hiya,


Sorry to hear about your little drama.


If it is the white wire to the pump that's shorted it would just let the smoke out, as it's unfused straight off the ignition circuit, which may also explain why it wasn't running too well!




If only the rear loom is damaged, you should be able to replace just that and maybe fit a line fuse into the fuel pump circuit to prevent any further occurrences!



Good luck with sorting it out.






SR Smith 1

That sucks...

If its the white then it probably toasted the entire loom, you will need to remove it and cut it open to see if anything else got cooked ... id do a resistance test on all the wires...to make sure

Im betting you probably burnt out your tach also, as thats sort of an unintended expensive fuse

Good luck

prop
Prop and the Blackhole Midget

Tacho wasn't working anyway and the way it's burnt it split the loom open - only the rear loom though- hasn't affected the from at all luckily

Rang the supplier who said they will do me a replacement loom for £40 so that's something but don't want to replace it for it to happen again

I'm thinking its snagged on the area behind the rear wing and vibration has caused it to ware through and earth
Can't think of any other reason
richard weaver

Id get the new loom for the 40 they are offering then work with what you have using store bought wire... once its sorted then replace with the new loom

Just for clarity... was your new loom working before the fire, or was this the looms titanic maiden voyage

Lucas wiring is known the world over as the prince of darkness... did you remember to submit your soul to lucifer, before you hit the ignition switch

Prop
Prop and the Blackhole Midget

The cars been running set about 1000 miles since full bare she'll resto - all new parts -I do remember it scraping a bit pulling it through the rear wing appeture so thinking that's were its worn through
richard weaver

Sounds like a plan

Prop
Prop and the Blackhole Midget

I would carefully check the routing of the loom, particularly where it enters the B-post.

Have you used any P-clips to secure it?

Also check where the trim panel is attached to the inner sill that it hasn't snagged the loom.
Dave O'Neill 2

Richard,
Cut the offending wire at the point that it melted, to isolate the length between that point and the pump. Then check with a meter for "continuity" between the cable and the bodywork. This will tell you if the insulation has chafed through and caused a short. Then disconnect the wire from the fuel pump as well to eliminate the possibility of a fault with that.

If there is a short, then the easiest solution is to abandon the damaged wire and run a new length of wire through to the pump. But of course it is possible that other wires have also been damaged by the fire.
Guy W

"-- rear part of the loom had completely split open and white wire melted through --- "

Almost certain to have melted adjacent wires insulation.

You should unwrap the loom each side of the melt, far along enough to check all the other wires insulation.

The reinsulate where needed, and re-wrap.
Lawrence Slater

I probably should have spelt out more clearly!

When I said "of course it is possible that other wires have also been damaged by the fire", I was meaning at other, hidden locations. Locations in addition to the obviously damaged wiring where the white wire had caught fire and split open the loom.Those are easy to fix! The issue being that the loom may have sustained other, less obvious damage.
Guy W

This thread was discussed on 12/06/2015

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