Different car loom !!!????

[BATTS91]

Right ive been helping a pal today convert his 2 door F reg 89 318 (m40) to an m20b25 .

Upon completion we turned the key and smoke bellowed out from the fuse box and relays .
Traced a melted wire from the white dme relay to pin 20 on te c101 plug .
Pin 20 on te engine loom is yellow/red . On te car loom its green or brown i cant remember now im home .
Also behind the glovebox there is the normal blue relay Plus two yellow ones ???
Both my e30's dont have these yellow relays and neither do my pals two e30's ??

I have heard of there being a rarity on the zone were similar has happend and the different loom was at fault .
Anyone have info on this or how to fix the problem ?

Thanks .

[jmc330i]

Bit late now I guess, but....
http://www.e30zone.net/modules.php?name ... ic&t=83367

[polsta]

I have the 2 yellow relays in my 325

[Brianmoooore]

Oh dear, another one just jumped in without checking on here first! This problem is not rare at all, and I've warned on here many times about it - it has it's own sticky in the engine swaps forum, and I'm sure it's documented in the wiki as well.
The red/yellow wire on pin 20 had full unfused 12 volts on it, straight from the battery, via the DME relay when you turned the key on, and the brown wire on pin 20 of the other half was an earth - a relic of when E30 brown coolant temperature sensors were two pin instead of one.
The relays behind the glovebox are nothing to do with the problem.
The DME relay is now suspect and the engine loom will be cooked, but these are both easily replaced. The big potential problem is that the brown wire will have melted where it goes down in a duct with dozens of other wires from the fusebox to the back of the glovebox area, and it's impossible to say which of the other wires it will have melted into.
The thin brown wire joins to a much thicker brown wire shortly after it reaches the glovebox area, so the damage shouldn't have spread any further than here.

[BATTS91]

Oh jeez ! His gonna be pissed Haha ! .

So first port of call i suppose is trace the wire into the car .

How do we correct the loom ? Ie disconnect one of them to stop from earthing out i take it .

Very big lesson learnt there i spose !

[Grrrmachine]

There's a Sticky on this in the Engine Swap section, AND a Warning in the Wiki "Loom" page:

http://www.e30zone.net/e30zonewiki/index.php/Loom#C101

[TPS]

Its wise after the event I know, but we did my M40-M42 swap, that section was checked & double checked, luckily mine was ok. I have a M20B25 knocking around if you get stuck.

[Brianmoooore]

So first port of call i suppose is trace the wire into the car .

That's where the problem arises. You can check the (remains of) the brown wire into the fusebox from the C101 and under the deck of the fusebox, but the big thick bunch of wires that go down into the car is the most inaccessible bit of wiring in the whole car, and is part of the main body loom.
The best you can practically do is cut away what you can, but there'll always be a question mark hanging over the rest of it, with the potential for a short to happen at any time.

[BATTS91]

Thankyou Brian much apreciated help . We'll get stuck in ina bit :/ .