Wiring Fun

[Surge 1]

Hey all,

We've put a Pre-facelift 2.5 M20 (Motronic 1) into a Facelift 320i (Motronic 2) now everyone I've spoke to has told me that they are about as compatible as South Auckland and full-time employment.

Sooo.. Just splicing ignition wires, and all other engine wires together will bring no joy (even though they use the same plug) - I know half of the wires don't line up, and some aren't there so not going to bother with this.

My solution is to swap the complete wiring loom out of the Prefacelift 325i (which the engine was sourced out of) into the Facelift 320i (of which the engine is going into)

By complete wiring loom I mean the fuse box and all, It's already been taken out of the 325i and wasn't that much trouble to get it out in one piece and only needed to cut out one wire. And by wiring loom I mean the whole car's wiring.

Now from there I am going to swap the speedo with the one from the 325i (Motometer I think, as opposed to VDO) - Just need confirmation of any additional Pre-FL and FL differences in the wiring department... Will the later fuel pump run on the earlier motronic etc....? (If not, it's easy to swap the bits over to make it run)

Cheers for your help so far, but wait there's more.

I'm going to put the facelift M20 2litre into my recently aquired for $450 Pre-FL 1986 318i, so I'm going to basically do the same for this as I mentioned as per above to get the 2.0 running in my car... Complete loom swap, sounds workable?

I'm only going to this much effort for the 2litre to have the provisions (Motronic 2) for an M50 which I plan on picking up in a few months time... That and the 2litre m20 has been well taken care of.

Now does this sound like a plan and a half and will everything after a bit of playing silly buggers run at the end of it?

One more problem I see coming up is the 320i is a sedan, and the 325i was a coupe - so will I be able to keep the rear electric windows or does the loom have provisions for rear windows and I'll be able to slot them right in?

Cheers for all assistance....

[ducatiss 1]

Will be very interested in how you get on - keep us informed. I have a Motronic engine to fit to an LJet at some stage.

[Gus 5]

reading your post v quickly...why not just change the engine loom and FL cooling system onto the Pre FL 2.5....then will work with the loom, just plug straight in. saves changing whole car loom. only prob then will be putting 2.0 into 318, but one may ask what the point of that is anyway? if you want more info on cooling system/loom swap email me

[ED1RTY 2]

e-mail this guy [email protected] he has done this before bout three times, knows the shizzle

[Surge 1]

Good point Gus re: swapping just the engine loom off the 320i onto the 325i - won't it have the crank angle sensor instead of the gearbox one?

The point of swapping a 2.0 inplace of a 1.8, I've got a manual box for a 6. I know performance difference between the 1.8 four and the 2.0 six is pretty negligable - hell the 1.8 is more fun to drive in a manual state

That and I've got all the bits essentially to give it the setup of a 325i, larger struts, sway bars, battery in boot etc.... So yeah, the 318i won't really have any memories of being a 318i after I'm finished with it.

I'm basically after just the late model motronic to make the planned M50 swap more straightforward while the later M20 will get me by in the mean time.

[Surge 1]

Update:

The 320i with the pre-fl 325i engine has all it's wiring removed, and the 325i loom basically put in - only things that I'm stuck with is a 8 pin connector under the rear seat - the colours of the wiring between the two looms don't match at all.. I really need to find out which wire does what so I can match it up. (it's on the drivers side)

And another thing, which is not essential but would be handy - has anyone wired rear window controls from a 2 door loom to a 4 door before?

[Carl 3]

reading your post v quickly...why not just change the engine loom and FL cooling system onto the Pre FL 2.5....then will work with the loom, just plug straight in. saves changing whole car loom. only prob then will be putting 2.0 into 318, but one may ask what the point of that is anyway? if you want more info on cooling system/loom swap email me

Best to discuss these in the open instead of by PM so that everyone can benefit.

I'm looking at putting a preFL 2.5 into my FL 320i, so the question is, can I still use my 320i loom?

My FL 320i has motronic 1.3 which has the crank sensors on the front of the engine, so, can I simply transfer the 320i loom onto the 2.5 engine and just swap the ECU's over, assuming that they'll swap over between 1 and 1.3....

Edited April 25, 2006 by Carl

[Surge 1]

Carl, from what the wreckers (Eurorec, and German Auto - both in CHCH) told me was that the two motronic's although similar in plugs etc... are completely not compatible.

The guy at Eurorec mentioned a story of someone matching up the wires correctly but needing to replace various bits and pieces (a 635csi ignition coil! of all things) just to get it to run semi-respectably, but even then it wasn't 100% in operation, hence why I'm using every single thing which came with that engine.

Carl, I'd assume if you did that (change the wiring on the ECU to the engine) wouldn't you end up with 320i engine management on a 325i? Is there a difference?

[topless 13]

The 320i with the pre-fl 325i engine has all it's wiring removed, and the 325i loom basically put in - only things that I'm stuck with is a 8 pin connector under the rear seat - the colours of the wiring between the two looms don't match at all.. I really need to find out which wire does what so I can match it up. (it's on the drivers side)

Important question... is your fuel pump in the fuel tank or under the car on the rear passenger side?

Also, can you confirm that you have put the complete pre-motronic 325 loom in your f/l 320? If so, what colour wires are you trying to join? (give both sets from the main loom and the plug under the rear seat).

I'm looking at putting a preFL 2.5 into my FL 320i, so the question is, can I still use my 320i loom?

Carl, I would use your 320 loom from your existing 320 motor and change over all the motronic 1.3 sensors from the 2.0l motor to the 2.5 motor. You will need to either get your ECU remapped or buy a 2.5 one as i am sure the 2.0 one will not fuel/time the 2.5 properly (but I may be wrong as I have not ever tried the 2.0 ECU on a 2.5 and had it dynoed to check what it does). And the motronic 1 and 1.3 ecu's are definitely not interchangeable btw..

[gmccormack 0]

Will be very interested in how you get on - keep us informed. I have a Motronic engine to fit to an LJet at some stage.

Motronic engine into L jet car is easy. I did it with my old 323 (now Andrews car) by making a simple adaptor lead. It plugs straight in and requires no mods to either the car loom or engine loom. Andrew, could you post a photo of the adaptor lead?

[Surge 1]

Important question... is your fuel pump in the fuel tank or under the car on the rear passenger side?

Also, can you confirm that you have put the complete pre-motronic 325 loom in your f/l 320? If so, what colour wires are you trying to join? (give both sets from the main loom and the plug under the rear seat).

The 325i (wrecked, engine source) the pump was under the car. The car that the pre-fl engine is going into is a 1990 320i (If thats any help as to where the location of the pump is, Dad's 1990 325i SE the pump is under - but don't they have one in the tank aswell?)

Yeah I've put the complete prefacelift loom (early motronic, you quoted 1.0? - I've always just called it "motronic 1 & 2") into the facelift 320i shell. This is going into my freinds car, my end of the deal consist of getting me a late model facelift loom (motronic 1.3?) for a future M50 conversion - heard it's easier! Not easy so far...

Sorry can't quote you on the plug colours etc yet as they are at the "workshop" (grandma's garage) on the other side of town - will get them for you tommorow.

[Carl 3]

Carl, I would use your 320 loom from your existing 320 motor and change over all the motronic 1.3 sensors from the 2.0l motor to the 2.5 motor. You will need to either get your ECU remapped or buy a 2.5 one as i am sure the 2.0 one will not fuel/time the 2.5 properly (but I may be wrong as I have not ever tried the 2.0 ECU on a 2.5 and had it dynoed to check what it does). And the motronic 1 and 1.3 ecu's are definitely not interchangeable btw..

Thanks, I suspected that was the case and i'm assuming the 2.5 will run off the 2.0 ecu which would be okay interim, last plan is to stick in a piggy-back unit and ditch the AFM.

Just to confirm, will my 320 Moronic 1.3 loom run off a 325 Moronic 1.3 ecu (assuming they plug together)??? Guss I could always borrow one to test...

[Surge 1]

Update on the wiring for you Will.

Ok, on the pre-fl 325i loom which has been installed in the car the plug (Plug on the drivers side - below rear seat, on both the new loom and the car) has the following wires attached:

(2nd colour being secondary on each wire)

1 Brown

2 BrownRed

3 BlueWhite

4 BrownGreen

5 BrownGrey

6 Green

7 Brown

8 GreenViolet

On the facelift 320i Car loom:

1 Brown (Medium Gauge)

2 Brown(with Red stripes accross the wire, not as per the usual strip down the whole wire)

3 Brown (Small Gauge)

4 Black

5 BrownLarge

6 GreenViolet

7 GreenBrown

8 BrownGrey

Also, out a seperate hole on the passenger side (again, under the rear seat)

On the facelift 320i Car Loom

1 BrownGreen

2 BrownGreen

On the pre-fl 325i Loom

1 Solid Brown

2 Green Violet

Now I'm assuming that there needs to be a few wires linked across to the other side of the car as the wires over the facelift may have been routed to the other side from that 2nd hole.. if you get my drift...

Any help would be much appreciated!

[topless 13]

I am up north at the moment, will try to post this weekend when I can get to my cars to cross-check things

[Surge 1]

Had a chance to look at your cars?

Cheers,

James