My Robin Hood nearly caught alight

[locost220]

So i was unsure if to start this thread as may well turn out that it is my fault this happened but as it may help others so what the hell.
So on Friday i was on my way to parents in Kings Lynn via most of a scenic route i have used to get to Stoneleigh, after approx 2 1/2 hrs the 'power lost' message came up on the TomTom that you usually get when you turn the ignition off, gave the lead a wiggle and a few seconds later the area beneath and behind the dash started to fill with smoke the smell of which was insulation melting.
As i was on a country lane i was able to pull over as i flicked the main battery isolator on the dash off ( key point 1 ), slip off Harness and jump out the car whilst shouting various absentees, flip up the bonnet catches and heave the bonnet / nosecone and scuttle combo up to see the smoke dissipating.
As there was no immediate risk i quickly grabbed a spanner and took both terminals off the easily accessible battery (key point 2 ).
After the heart beat returned to near normal i decided to have a look around hoping i could locate and sort out the issue as i had a rather good weeks driving planned, using the sniff test realized that the remains of the melting smell was still evident in the fuse box / main wiring loom under it area on the front of the tunnel.
As far as i know I am the forth owner of the car and had plans to revisit the loom and fuse box as it appeared that the original loom had been stuffed in as was and needed tidying up at least ( was on the to do list ), from having a look around it appears that the ignition pos 2 circuit had suffered a short and melted the insulation off for a fair distance that i could see already as well as partly melting adjourning wires insulation, including one of the wires on the brake res switch.
Due to the position of the fuse box and wiring it took me a only a few minutes to decide that although i could probably try and trace out and replace the obviously affected wires at the roadside i would not be able to check any of the hidden ones including under and around the rear area and the best and safest course of action would be to leave the battery disconnected then get the car moved home for a thorough check of the electrics with a mind to also cut out the unwanted wires and circuits to improve the situation overall, this might mean a new fuse box as i have done previously on the Locost during the rebuild.
So a call to insurance/recovery section had me uplifted in less than two hours to be moved to a Motorway services and a much longer wait till i got second trip home.
Back home the car was pushed in the garage and i quickly moved what was needed into the road car and came up to Kings Lynn the following day for a few days rest !
No real pics taken of the wires at the time, but will put some i did take for effect, so looking forward to taking the full bonnet, scuttle nose cone section off completely and to one side so i can crack on with checking once i get home in a week or so. Point to note i did also make sure that despite loading loads in the car for my trip i did make sure that the fire extinguisher was still accessible if needed.

[Wingco]

Sorry to here this Richard, glad you were quick to turn the power off, good thinking.
Do you think it will require a complete rewire ? I had the same problem with my old kit car, smoke coming out from the bulk head on the passenger side, gave the Mrs's a fight But saying that, this was all my fault you learn on the job with a kit car.
Hope you can sort that bit out so you don't miss this good weather.

[DJ.]

I hope the damage isn't too extensive.

This story does show how important easy to reach safety equipment is. Last year I fitted a battery cut off switch that I can reach from the drivers seat, and close to it is one of those fire stick extinguishers. I hope I never need to use them, but last year we had smoke from the engine bay and it is a frightening experience! Fortunately, in my case the auxillary belt tensioner had jammed and the smoke was from the friction of the crank pulley on the belt.

[locost220]

So a couple of evening in (approx 6 hrs), managed to get the windscreen, scuttle, bonnet and nose cone assembly off with not too much hassle and help of daughter, got it sat on the leader on the trailer.
This as expected has made the work so far a lot more easier although I recon I might still end up with washboard stomach the way my muscles feel after a few hrs lent over the car (if only ).
From past experiences it is not always possible to find the exact cause of such issues and this is no different, but tracing the hot spot it looks as if the worst burnt small cable is the earth part of one of the light Column switches and it has been squashed up against a mains feed to a relay. The relay, relay base, supply to it and the earth wire all being burnt or melted.
There is also melted insulation from the earth cable on adjacent cables throughout the loom but no damage to the later conductors.
So far I have quickly managed to replace the earth wire and remove the pieces of insulation stuck to the other cables. I intend to rewire the fuse box to use an unused relay housing to replace the burnt one.
As expected it appears most of the donor loom has been left and crammed into the box unit under the fuse box on the tunnel, as if the builder was not fluent in wiring, soldering etc, I have started to trace out the unused plugs, wires back to source, cutting out a few metres already.
Once that is done there is still far too much cable between the tunnel top and the fuse box that can be shortened by a fair amount and still leave room to flip the fuse box if needed, in doing this I hope to remove where possible the sections of damaged insulation mentioned above or replace it with heat shrink.

[greenwoo]

on the upside, the car will be a couple of kilos lighter once you sort that spaghetti out....

[DJ.]

Well done Richard, looking at that loom makes me realise even an 80s car had way too many wires for a Seven. Both my Westfield and Caterhams had purpose made looms and the saving in weight and time building was well worth the extra expense.

[b33fy]

Good job Rich. Wiring can be a right pain. I had an MG Midget that decided to set fire to itself. The feeling of blind panic has never been forgotten. Unfortunately I managed to save the car for another day of sardine can motoring until it blew up and fell apart with rust, pretty much concurrently iirc.

[locost220]

So over the past week I have managed about 6 hrs initially replacing the burnt wires and then the whole process of trying to remove the mass of redundant wires still in the loom from the donor sierra, this included the across engine bay loom that was doubled up across the tunnel top, cutting back and or removing wires and relays not needed such as rear wash wipe and powdered seats, or shortening where required.
I have also taken the opportunity to tidy up wiring on some upgraditus that has occurred since it was built, I intend to relocate a few added on relays to the fuse box to make it look neater as well.
I was finalised beaten today after 10 hrs due to aching legs, back and red raw chest from laying across the dash.
There are definitely lesss to do as it is getting harder to spot the ones left to do and the pile of removed cables is getting bigger.

[DJ.]

Well done!

[locost220]

Clocked in the garage ( or second home as Swmbo calls it ) for another shift, had to shorten and re route a few wires to let them come together in a reasonable bunch with cable ties still at this stage till testing is done.
Then cut out and redid a few more of the add on’s from previous owners, then thought sod it let’s whack the battery leads on and stand back ( holding a fire extinguisher), no sparks or bangs so I push on a bit further and have a walk round the front to find the dipped beam on, this was the circuit involved with the smoke and has ruined the original relay and I had already nicked another relay off the car that turned out to be a normally closed relay and not the normally open one that was required, once this was sorted the lights would then not come on a all due to some doughnut not replugging the column switches in, once that was sorted only one of the main beam would work that was due to a big gap between two ends of the wire, once that was soldered back in that then worked.
After a bit of chuffness after I ticked all the rear lights and indicators off the list I got the easi start out (battery was a bit flat so needed all the help it could get ) couple of squirts and a turn of the key and it fired into life, let it warm up, made sure the fan override worked as well as the gauges springing into action, all good except a burning smell from the brake res plug resting on the now hot exhaust manifold and no gauge lights, so a couple more things to sort before I can start to tape up the loom ready to bury under the Ali cover and fuse box. Well chuffed so far ( disconnected the battery just in case )