Smoke under glovebox! Troubleshooting hints anyone?

[jhm]

Engine (350i -87) stopped yesterday and a burst of smoke came up from under the glove box!?
Stopped at once and disconnected the battery. Has trouble shooted this far:
Has sparks and engine runs on ether when injected into manifold. Fuelpump fuse is not blown. Jumper cables on fuel pump does not make engine run. Under the glovebox (LHD car) I found the source of the smoke, a brown wire that now has very little insulation left.

I have the wireing diagram in Steve Heath Wedges book, but unfortunately I can not understand the colour coding properly. If B is black what is then Brown? I would have guessed BR or BN but there exist no such code!

Help any one?

JHM

Edited by jhm on Sunday 22 April 13:16

Edited by jhm on Sunday 22 April 19:56

[s.hogan3]

how long is a peice of string if you can post couple of pics of the wireing harness at fault this might help us understand the problem
if you cannot post them on p/h
e/mail me your pics as im a auto electrician and will try and help you as much as i can
hope this helps you

[wedg1e]

Brown is N. That'll be a main feed cable by the sound of it.

[jhm]

Thanks so far. N being brown makes sence for what I have found.

I think I have found the cause of the problem. There is a brown/orange (NO) wire feeding the power resistor and the air flow meter. On an LHD car it passes just over a bracket... short cut! Insulation is gone there. This wire comes from the main relay. That relay shows traces of over heating. Trying to continue on the way to the battery, it turns brown and then later going down in diameter, that is where the smoke must have come from because there the insulation is just about off completely. It looks like this wire goes into a lot of other brown wires on the far right of the car under the dash board.

Hope I can get access to the end of that melt down wire. I'll look for a new relay tomorrow and some evening this week when I have time I will replace it and hopefully get a new wire in place.
Any chance that some other component might have taken damage of this short cut?
The relay schematic in the Heath book doesnt make sence to me (page 266) where are the main and fuel pump relays in that diagram? Does some one have a better diagram?

[andgus]

Would be interesting to have the whole colour coding for the wiring....who could have guessed that N was brown? Not me, that´s for sure!
/Anders

[jhm]

From what I have found around the main relay,
B=Black
N=browN
W=White
U=blUe
Y=Yellow
O=Orange
I will probably learn af few more codes the coming days...

[andgus]

Good.....don´t forget to let us know.....:-)
/Anders

[jhm]

The real cause of the problem must have been someone replacing a water hose. When leaving Blackpool the harness must have been above that hose, now it was below.

What I now have done is rerouting the hareness, adding new insulation where the damage was, replacing the main relay that showed signes of overheating and replaceing the burnt wire going to the relay.
Now it runs again!