Wiring Problem - Smoke in Cabin!

[Smo]

Hey guys, as typical before a show, something has gone wrong with the R, lol.

I replaced the radiator today (had expansion nipple welded back on) and took the car for a run, oil temp good, water temp good, all readings fine. Until I notice smoke coming from under the dashboard and filling the cabin!

I pulled over, turned it off immediately and this is what I found;

Looks like I managed to catch it just in time and no harm seems done to the car.

This section of loom has melted in places all the way along, above the pedals in the cabin it has done the same. I've left the car with the battery disconnected for now. I can only imagine I've managed to pinch a wire under the slam panel when I was refitting it perhaps?

Is it possible to replace this section of loom or will I have to strip it apart and trace/repair/reinsulate each and every wire?

 

[sharpygti]

that would be the main car loom then. ud have to strip everything out to change that sam. thats alot of work

 

[sharpygti]

i changed the main loom on a proton rally car a few months back. most of the car was stripped out anyway being a rally car and it still took me a day

 

[Smo]

I thought the main loom was the big bugger right next to the rocker? It seems to me like this smaller one is the alternator/rad fans etc?

 

[katemc]

to be honest if it was just under the bonnet bits id be tempted to cut the old out and re-wire.
But if its in the cabin too it could of done more damage that wont be visable, may be a good idea for a new loom.

 

[Smo]

to be honest if it was just under the bonnet bits id be tempted to cut the old out and re-wire.
But if its in the cabin too it could of done more damage that wont be visable, may be a good idea for a new loom.

That's what I'm not certain about - I suppose the only way to find out would be to begin stripping the loom in the engine bay and follow it back.

 

[pulsarboby]

new loom i reckon.
this happened to gtirpimp recently pm him as it was a nightmare to sort out and ended up costing a lot of money as it will track back to source.....if you miss one bit of wiring then youll have further probs which you dont want seeing as youve just had all that bodywork done.
you need to find the exact cause of the burnup

 

[Smo]

Excellent. Just in time for JTS too! Do you reckon it's worth trying to trace the problem or should I just go for a new loom right away?

How much do you charge for a loom Bob? I'd rather just replace it all right now rather than attempt a repair if it can have consequences.

 

[saddler]

Ahh crap Smo that don't look. have you shorted the Rad fan wires ? Real sad if you can't make JTS

 

[sharpygti]

just rip it out and change it, faster, easyer

 

[pulsarboby]

Excellent. Just in time for JTS too! Do you reckon it's worth trying to trace the problem or should I just go for a new loom right away?

How much do you charge for a loom Bob? I'd rather just replace it all right now rather than attempt a repair if it can have consequences.

track it back and see how much you need, my guess is that it goes back to fusebox, i need to know what part it is as theres shitloads of wiring under the dash.
if you were local i would say take it out yourself foc, but you aint.

 

[jambo_gtir]

Oh dear mate that is a shitter!!
You would have thought that a short would pop the fuse, thats what they are for. Someone must have replaced a certain fuse for a larger one at some point, as that wiring should have been protected....

 

[pulsarboby]

not necessarily, some wiring is not fused and runs via a relay (which is basically an electronic junction box) or some feeds are direct live and unfused.
the problem is finding the initial cause of the burn up as it may not be the wire/s that have burnt back through which initially caused it.
electrical probs like that can be a real nightmare to sort out so as said the best way to do it is by replacing the whole part of that loom to make sure nothing is left to short out again
i fooking hate wiring faults.... but hopefully in smos case its nothing too serious

 

[jambo_gtir]

i fooking hate wiring faults....

lol, especially when you try and follow the circuit/wiring diagram for the car. I had a look the other day at it and was amazed at how complicated it was. But then im used to ours at work which make sense and are drawn to proper conventions :lol:

 

[Smo]

Right - what a fucker!

I dove head first at the problem today as I want the car driving for JTS, and all I can say is that I've been a lucky, lucky boy! Not only did I catch it just in time to avoid the car catching on fire, I also managed to locate the source of the problem and have determined that my ECU was an inch away (literally) from getting fried. But more importantly, I can fix it.

This was the culprit;

Turns out the short was caused by the wire running to the AVCR boost solenoid being pinched under the slam panel directly onto a small chip on top of the radiator (see below). If you look closely you can see above the left-hand side of the bonnet catch the loom is crushed flat, and just to the left of that is the small chip that it caught on;

All it took was that tiny contact point on the loom to fry the line entirely, it burned through the grommet, into the cabin and up to a plug next to the drivers door (my AVCR is mounted in the top-right corner of the windscreen), it also ran above the foot pedals where the loom is spliced into the Power FC ECU.

As you can see from the image above, I was so, so unbelievably close to frying the ECU. The burned wire from the boost solenoid is spliced into the orange wire on the far left of the picture which is miraculously undamaged. I can't believe how close I was, god knows what would've happened if I had turned the car off 10 seconds later.

The below image is the junction where the AVCR loom splits from the solenoid to the controller and the ECU, you can see the damage caused by the red wire. I can't believe how lucky I am that none of the wires touched each other. I followed the wire after pulling it through the grommet into the cabin and tracing the entire thing. Almost all the red insulation was burned away but no damage was done to any other wires (aside the neighbouring pink wire). This was a very, very lucky escape.

Here's a shot of the frazzled red wire between the radiator and bulkhead;

Now what I plan to do is entirely replace the red and pink wires between the solenoid and black plug to the controller. From there I am also going to completely remake the loom from the controller to the ECU myself just incase there's even the tiniest contact point I might have missed. Effectively rebuilding the AVCR loom from scratch.

My question is do I need any specific kind of electrical wiring to do this? I plan to use the same colours where I can to avoid confusion, but I need to know if the wires are unique in any way or if I can use a generic wire.

 

[pulsarboby]

cant answer your question on what wire thickness to use etc as wiring is not one of my strong subjects lol

but i will say very well done sam for finding the initial fault
yes you are very lucky that no damage appears to have been done to ecu.
at least you had the good sense to pull the batt connection off rather than just turn ignition off which some people would have done

 

[Smo]

cant answer your question on what wire thickness to use etc as wiring is not one of my strong subjects lol

but i will say very well done sam for finding the initial fault
yes you are very lucky that no damage appears to have been done to ecu.
at least you had the good sense to pull the batt connection off rather than just turn ignition off which some people would have done

Mine either Bob, I hate wiring!

Cheers for the support though, what a bugger of a situation lol. I still have my AVCR installation manual so hopefully I'll find the information I need in there. I'll have a look after work.

Will be interesting rebuilding a loom myself too!

 

[RO_SUNNY]

Check the ecu also because it seems that you've fried wuite good that loom.

It's a pity to see that this happened to you........but that's life.

Myself I've put a general kill switch to stop allt his problems....

Anyway on 12 volts all cables will burn in 20 seconds....so there's not much to do.

In my opinion yopu should strip the entire front end wiring and repair it and then insulate it properly.....keep in mind that this cars have 20 years of living and everything is old on them

 

[Smo]

Andy and I set to work today and completely rebuilt the AVCR loom from the controller to the ECU and valve solenoid. She's running perfectly, even better than before and all sorted!

 

[JIMMYBACK]

Wow welld one fella this reminds me of a wiring issue when my poor car was running, the thing is myinn did catch fire so i had to cut the cables out there and then:shock::doh: