Need help, e36 m42 into e30 318i m40

[Home_made_iS]

Ok so Im changing out my 1990 m40b18 (8v motronic ecu) in my e30 2door for a m42b18 out of a 94 e36, im awae that i have to change the sump and location of a few minor things. my problem if your willing to help me out slightly is that i have the m42 engine wiring loom up to the interior loom change over plug, the big plugs are different (i cant remember the name of said plug) obviously because of the difference in years the systems will be slightly different for new options and so forth on the newer engines, is it posible to put a cenversion plug of sorts in place between the wiring loom plugs? (im aware this sounds kinda far fetched). Also is it possible to use the e30 8v air flow meter on the e36 16v engine, the plugs have 1 or 2 contact points different between them (im assuming thats for the DASC on the intake manifold or something of the like)

OR
just get the rest if the e36 wiring loom, instrument cluster, and any other associated pieces) and what other airflow meters fit this loom?

Any assistance on this would be extremely appreciated, also anybody who may have parts to suit like e36 airflow meter etc. and may want to get rid of them, Im automatically interested.

Sorry for the long winded post, this shits frustrating me at the moment
Thanks

[FredK]

Ok so Im changing out my 1990 m40b18 (8v motronic ecu) in my e30 2door for a m42b18 out of a 94 e36, im awae that i have to change the sump and location of a few minor things. my problem if your willing to help me out slightly is that i have the m42 engine wiring loom up to the interior loom change over plug, the big plugs are different (i cant remember the name of said plug) obviously because of the difference in years the systems will be slightly different for new options and so forth on the newer engines, is it posible to put a cenversion plug of sorts in place between the wiring loom plugs? (im aware this sounds kinda far fetched).

Yes.

The 20-pin round connector that passes signal and power through the firewall is called C101 on the E30. The E36 uses a 25-pin round connector called x20. You can make an adapter if you're feeling brave.

For this to work, you must use the E36 M42B18 DME and wiring harness.

I am not sure if you have to swap over the intake manifold stuff in order to clear the hood? If you can find an M42B18 from an E30, plunder it for the intake manifold, maybe even the complete wiring harness and DME if possible. This would make the swap a lot easier.

Also is it possible to use the e30 8v air flow meter on the e36 16v engine, the plugs have 1 or 2 contact points different between them (im assuming thats for the DASC on the intake manifold or something of the like)

OR
just get the rest if the e36 wiring loom, instrument cluster, and any other associated pieces) and what other airflow meters fit this loom?

I looked into this on the BMW Parts database (ETK).

There was a parts supersession on the M40B18 air flow meter to PN 13627558785, which means you SHOULD be able to reuse your 8V airflow meter with the E36 engine, provided you splice the M40 electrical connector to the E36 wiring harness.

[Home_made_iS]

Thankyou Fredk that clears up a couple of things.
would you happen to know if the m40 8v intake manifold will fit, negating the need for the later model intake electronics? im not trying to cut corners just wrap my head around it without tearing up the entire car, if it helps i have an entire m10 powered 318/5speed if any parts may be interchangeable (spare car)
thanks again

[Home_made_iS]

i also have the ecu from the e36.
but thanks any ways'

[FredK]

I'm am fairly certain the M40 intake manifold will not fit. The M40 intake ports are vertical and circular, and they are angled and oval on the M42 head.

[Slick92GS-R]

i just recently used an E30 M42 as a replacement for my E36M42..

there is a certainly difference between the two harnesses..

let me know if you need any E30 M42 specific parts

lol.. i just figured out that you are in Australia ..

[Home_made_iS]

thats ok, thanks any ways i may need ot oreder parts from overseas anyway at this point, apparently e30 m42 parts are hard to find in australia. dammmmmit

[Home_made_iS]

ok, ive now got it all in and turning over, but from what i can tell the ecu is not switching on when its turned to start. I have no fuel pump but all wires that i know of are connected.
Does anybody have a complete dme 1.7 pinout diagram?

or possibly somebody has done a similar swap with an e36 m42 into e30 m40 and has a diagram from theyre experience, its not that im trying to take the easy way out, ive been tracing wires for 2 weeks and i still cant get all the right diagrams and colours to get everything pumping.

if any body may have made a conversion table between 1990 e30 c101 and 1994 e36 x20 engine plug that i may be able to borrow as i have not been able to find one to suit the m40 non abs only the m10 or m30 which are all slightly different engine harnesses.
i have checked that its a manual ecu, so no park sensor.
any help would be greatly appreciated

[keen]

Hi there I suppose you have finished by now but I have some points you might find interesting and maybe you could try these or maybe you have already done these. The sump needs to be changed and I wonder if the sump from the m40 will fit the m42? there would be the associated oil pickup needed but the blocks should be the same so I would have thought it would all fit.The loom from the m42 in the e36 is on the opposite side and in the engine compartment. Could you "U" turn it and bring it back into the compartment of the car where the m40 one comes back to? you may have to cut the loom outer casing for that to bring the relevant wiring back. but I am thinking that that would not be a biggie then you can use the ECU from the m42.I'm not too sure about the park sensor. is your car an auto or are you trying to put this into a manual? Please let me know how its going I'm in the throws of the same conversion .

[Joel McCarter]

i was thinking about doing the exact same thing to my 1990 318i

[Home_made_iS]

hey all sry for the shit replys.
conversion done, u can tell it was done at home but other that that works fine, everything (that u needs anyway) from the m40 bolts straight to the m42 (upper and lower sump, oil filter, power steering etc) was actually a really easy conversion. i lost all my handwritten c101 - x20 wiring diagrams which was the only real issue with the whole lot.

overall worthwhile conversion for the $2000 or so it cost all up

back on line now pm if anybody is still doin this swap and has questions

[e30yttocs]

can anyone please help me with the wiring please ?

[TwoTees]

Hi,
Its been a while since this thread last saw interest but I am hoping someone can help with a few questions.
The car is a 1990 e30 M40. (Right hand drive for exhaust issues)
Also keep in mind e30 38is is very rare here in Australia so finding the e30 m42 parts is difficult.
I have a complete M42 from e36 including e36 Exhaust headers and engine pipe, all ancillieres, pumps etc. loom complete to ECU air box/meter pipe.
I have sourced e30 m42 headers but not sure if m40 engine pipe will simply bolt to them.
I am good with the actual change of sumps, engine mount arms, ancilleries ect. and the general install, but cant get good info on the wiring required and a few other possibly trivial points.
Shall I keep e30 M40 loom and just modify the relevant plugs to engine points/sensors ignoring knock sensor or use e36 loom and cut the plug off the end and join the e30 plug. If so can you offer any advice. I did read somewhere they are colour for colour.??
Do I run m40 ecu? M40 air meter/box.
Will the e30 or e36 rubber intake tube fit? or will this need to custom
This is my sons car and really want to do it in a weekend so I am trying to be clear of all the little things that crop up.
Thanks in advance
Regards, Chris