4 Cyl to 6 Cyl Engine wireing?

[fastcarz464]

can anyone who has done the 318i to 325i conversion please give as much info on the engine wireing as possible, my car has had the 318i engine, box and diff removed, i have a 92 318i cab and puttin in a 90 325i engine box and diff, they are puttin in everything except the wireing, so ill be doin that with your help , cheers!

[Andy325i]

should pretty much plug straight in (you need the 6-cyl Engine loom that plugs into the socket on the bulkhead. Engine will work no problem, just (MAY) need to swap a wire to get the heater fan working

[fastcarz464]

cheers andy, they will be gettin everything off the doner car into mine on tuesday, where does the wireing go, i know its behind the bulkhead to the fusebox? i think but do i have to wire anthing inside the car? what about the ecu, do i just unplug 318 one and plug in the 325 one in? cheers

[Brianmoooore]

The engine ECU connects on the end of the engine wiring loom, which goes through the bulkhead on the right hand side.All the main things should work ok, although wiring for the odd thing like an oil level sensor may be missing from the car loom.

[Brianmoooore]

Andy 325i - I'm intrigued by this one. Something I've never come across before. What on earth is the connection between the engine loom and the heater fan?

[fastcarz464]

cheers guys, i carnt wait to get this engine in, how would i know if stuff aint working like oil level sensor etc, and if it dont work, what do i need to do to make it work? is there any insructions on this conversion on the net? cheers!

[Brianmoooore]

If your original 318 didn't have a check module (box with red LEDs above rear view mirror)of which the oil level sensor is part, then the C101 plug and socket ( big round one on bulkhead, just inboard of the fusebox), will not have the wiring for the oil level sensor in the car part of the loom.
To restrospectively fit a check system, you would have to change nearly every loom in the car.

[Andy325i]

Hi Brian, when I converted my 1990 318i to a 325i the heater fan didn't work, so I made a link in the fuse box. I guessed it was a pin out of place, but didn't know what all the pin uses were for so didn't want to go playing. Sure some of the boys on here have moved the correct pin sucessfly though

BTW does anyone have a pin out for the bulkhead connector plug?

[Brianmoooore]

Yep, worked these out when I did my M50 conversion.
This is from a 1990 325 Touring.
1/ Thin blue - ignition light
2/ Thin green/yellow - oil level
3/ NC
4/ Thin brown/purple - water temp.
5/ Thin brown/green - oil pressure
6/ Thin green/white - power from fuse 9 for lambda sensor
7/ Large green - ignition 12V+
8/ Thin white/blue - fuel rate O/P to A11 on cluster
9/ Thin black - engine speed O/P to A7 on cluster
10/ Thin blue - oil level
11/ Thin white/green - Diagnostic pin 7, reset service ind.
12/ Thin grey - engine ECU check light
13/ medium green/purple - fuel pump
14/ Thin black/white - speed signal to cluster
15/ Thin black/green - small terminal on starter motor (unloader relays)
16/ Thin white/black
17/ NC
18/ medium black/yellow - starter solenoid
19/ NC
20/ red/yellow - 12V+ from battery, when main relay closed to ABS

Don't take these as absolutely accurate, but most are correct.

[Brianmoooore]

Andy 325i - looking at what I've just posted, I would think your heater fan prooblem was with the black/green wire on pin 15.
This earths the unloader relays, K5, K6 and K7 through the coil of the starter solenoid. The idea is, that when the starter is operated, these relays drop out, and disconnect several items, while the starter is operating.

[fastcarz464]

brian, thanks for the help, my 318 does not have the check control, but most prob the 325i i get will have one, is this going to be a problem? what are the chances of just plugging the c101 and everything working 100%? is it most likely im gunna get loads of problems?
Another thing, i have full adjustable koni suspention, is this going to be ok when the 325 goes in or do i need new suspention and brakes?and also, do i need to change the clocks? cheers!

[Brianmoooore]

You will need to change the coding plug on the clocks for a 325 one.(lower right hand side of front of cluster - no need to remove cluster from car).
All the essentials should work just be swapping the looms at the C101.
Suspension wise - standard 318 struts are of a smaller diameter than 325s, but that doesn't matter. 325 engine is heavier than the 318, and 325s front springs are stiffer than standard 318s.

[Andy325i]

Brian - you have an M50 conversion? :D:D

I have an E30 320i that I have a M52 waiting to go in. Do you have any pics or info mate?

[Brianmoooore]

Yes, did it last year, using a M50 2.5 single vanos engine from a 93 525i, into a scruffy Touring shell.
Been up and running for a few months, but only done about 200 miles so far, as it's not MOT'd/taxed/insured yet. Aquired a 3.09 diff and a 735 air filter box three weeks ago to finish it off. Diff is fitted and I'm hoping to finish the air filter this afternoon. Plan then is to get it on the road for long term testing, and then to transfer the whole lot to a mint silver Touring that I bought a few weeks ago (write off because of engine fire).
I didn't start with any info. other than a little from the German site, and kept full notes of everything as I went along.
Anything you want to ask, feel free.