Where did I go wrong M42 swap

[steve3smart]

This is my first 4cyl BMW, I always had straight 6's before hence the lack of experience with this engine. I just fitted a 95 M42 engine into my E30 M40, complete with serpentine belt drive system, wiring loom and ECU. Everything fitted in fine, just had to shorten the M42's dipstick and mount it towards the front of the car. I rewired a spare C101 plug to the M42 harness. The engine is cranking over but there is no spark. I checked all the harness adaptation at the C101 and seem's all in order. I'm guessing from all I've read that it is an EWS issue. What is the best way around the problem? I read one member fitted all the E30 sensors to an M42 and simply used the original harness. Is there a quick fix to this problem ? 

[bmwman91]

If you put on an E30 M42 intake manifold you should be able to run with the E30 M42 harness, although you will also lose the knock sensor function. I have no idea how to bypass the EWS, but I would imagine that you have to get a custom chip for that.

[DesktopDave]

I've heard of two short solutions.

First, tape the original E36 key to the EWS antenna, connect the EWS box & tuck it all up behind the dash somewhere.

Second, cut the EWS harness wire & splice it. I'm not sure what wire nor what colors it might be, but the EWS harness should have some thicker wires to indicate which carry more amps...those are the important ones. If I had a complete E36 setup I could tell you, but mine is missing the EWS junk. IIRC they're a plain green wire and a green/black wire.

[bmwman91]

Ha! So you can pretty easily hot-wire an EWS car if you just cut & twist the right pair of wires?

[DesktopDave]

Pre-OBD2, anyway. From what I've heard via my BMW Master Tech buddy, the EWS-II system ('92-'95) only used a transistor box to inhibit spark, much like the old CODE anti-theft boxes in OBC system. I had heard that you'd also need a non-EWS DME, but he claims that you don't. There are also DME EWS delete chips by MarkD and Dinan. I think Barrie might have one too, have to double-check his web site.

The later OBD2 system (EWS 3) is significantly tougher. It uses an encoded signal to the DME, meaning that the cluster, DME and keys all have to match. BMW will align them for you, but dealers tend to be pricey. I believe that there are a few EWS delete chips for them too.

Information is confusing on this type of swap. There seem to be about a thousand success stories, but many are fakes. The attention-starved teens on BMW sites like R3v tend not to be a reliable source of info.

[benz-tech]

Hijack: so you're sayin I need a cluster(E36).  damn

[DesktopDave]

I don't think you NEED a cluster for the swap, just the key & antenna along with the EWS box. You'd have to sort the C101 as well. I found this nice little chart here for the E30/M50 swap. I'll bet the M42 would be very similar.

It's be nice to have the E36's little digital warning display and all, but you can splice the E36 harness to send signals through the E30 chassis harness to the E30 cluster. I'd think for the E30 cluster you'd need the following six signal wires at a minimum: alternator, CLT, oil pressure, DME speed signal, CEL and the injector duration. The C101 has a lot more wires but several are just for the OEM GT1 diag hookup.

[benz-tech]

Thanks and good to know. My only worry is that there is some sort of data transfer between the cluster and the DME for info such as coolant temp, tach signal etc.  At leas I have the EWS and key.

[steve3smart]

Thanks for the replies.  I've been looking at EWS bypass chips, there is one here on Taiwan Ebay but Im not sure if it will work with my ECU. The numbers on my ECU are 0 261 203 590   and 1 743 250 001. I have asked the seller but he doesn't know if they are compatible. When I bought the engine I only got the complete engine harness and ecu. Can I use an earlier E36 Ecu?

[DesktopDave]

I'm not sure of those numbers. It's my understanding that there are only three M42 DMEs. There's the E30 version, 175, with no knock and no DISA. There's the non-EWS E36 (purple label?), and the EWS (silver label) version. Some DMEs have the Bosch part number in different places, so it can be difficult to tell which DME it actually is.

Did you try to PM Barrie about his DME delete chip? He's "BMWConnect" on the forum here, and over at 318ti.org as well. He should know exactly what you have, and should have a quick solution to make it work.

This looks fun too, not sure if it works:
https://www.youtube.com/watch?v=1l26whvF-3k

[steve3smart]

I'm not sure of those numbers. It's my understanding that there are only three M42 DMEs. There's the E30 version, 175, with no knock and no DISA. There's the non-EWS E36 (purple label?), and the EWS (silver label) version. Some DMEs have the Bosch part number in different places, so it can be difficult to tell which DME it actually is.

Did you try to PM Barrie about his DME delete chip? He's "BMWConnect" on the forum here, and over at 318ti.org as well. He should know exactly what you have, and should have a quick solution to make it work.

This looks fun too, not sure if it works:
https://www.youtube.com/watch?v=1l26whvF-3k

Thanks Dave. I'll e-mail Barrie. It'll be great if I can get a performance/EWS bypass chip, or another quick fix. I'm doing the work on the car, but it's sitting in a local garage. I feel like it should be finished and out of there by now.

[DesktopDave]

Thanks Dave. I'll e-mail Barrie. It'll be great if I can get a performance/EWS bypass chip, or another quick fix. I'm doing the work on the car, but it's sitting in a local garage. I feel like it should be finished and out of there by now.

I hear that! We've all been there...are there...will be there again. My '84 745i is still sitting, should have been done before winter! Barrie knows his stuff, he'll get you rolling.

[selespeed]

This is my first 4cyl BMW, I always had straight 6's before hence the lack of experience with this engine. I just fitted a 95 M42 engine into my E30 M40, complete with serpentine belt drive system, wiring loom and ECU. Everything fitted in fine, just had to shorten the M42's dipstick and mount it towards the front of the car. I rewired a spare C101 plug to the M42 harness. The engine is cranking over but there is no spark. I checked all the harness adaptation at the C101 and seem's all in order. I'm guessing from all I've read that it is an EWS issue. What is the best way around the problem? I read one member fitted all the E30 sensors to an M42 and simply used the original harness. Is there a quick fix to this problem ?

I have this exact problem in july 2013 on my april 1994 e36m42 on my e30. it wouldn't fire up but It cranks.  after days of scratching the head, it turned out that the mechanic did not connect the ground wires properly. as there is no diagnosis too.

check the connections. and there is also a write up on ews ecu by pass.

[steve3smart]

PROBLEM SOLVED. Big thanks to Desktop Dave, and BMWConnect, The quick and definitive answer is there is no EWS bypass for the 0 261 203 590 DME.   I needed an earlier DME.  Pelican Parts has a good list of DME numbers with corresponding Bosch systems.  According to the list what I was looking for was 1994  0 261 203 282 unit the Bosch Motronic M1.7.2.  Luckily for me there was one on  a local auction site.  Bought it, plugged it in and the car started. Now I just have to finish fabricating the exhaust front pipe, shorten and tidy the wiring harness.  All in all the swap wasn't difficult. I'll post some photos when it's all finished.

[DesktopDave]

Awesome! Off-hand, does that 282 DME have a purple label?

Isn't that EWS system a massive PITA? WTF, you buy a car but somehow you don't completely own it? I'm told that a dealer can re-align the old DME, but I'll bet it won't be cheap...