Help with Wiring for 87 M30 Motronic swap...Please.

[bimmeup02]

Hi, I have a 79 633csi (it is e12 based not e28) and I have installed the complete motor with motronic from a 1987 535is to replace the dead 3.3L. Where I made my biggest mistake is Assuming that there would be ample information regarding the interface of the Motronic Harness' C101 connector interface to the Stock e12/e24 fusebox. I want to do a very completely functioning, neat and tidy interface, and so I plan on making a Jumper cable with the appropriate connectors that I have acquired from the needed vehicles (I have the fusebox female end from an e28 to plug into the Motronic harness, and I have the old e12 fusebox male end to plug into the stock fusebox, and I plan to mate these two to make the jumper) I have been able to find plenty of info on e34 to e28 3.5 swaps, and plenty have done the e12 3.4 and 3.5 swaps, but it appears most have retained the old L-jet injection...I am upgrading for Performance and Economy, both of which are unavailable with L-jet. My stock e12/e24 fusebox connector has 12 Pins which 10 are wired (2 doubles for a total of 12 wires), and the C101 connector on the B34 has 17 Pins of which 15 are wired, what I am looking for is a diagram(s) that actually contains Pinout wiring information for the connectors. There are some really good writeups in the Technical FAQ section, but none of them Actually addresses the info that I need, the one writeup about the e28 wiring conversion addresses the 8 pin connector on a 520i (a 520i is a 4 cylinder model, obviously not a US car) I need the pinout of a 12 pin connector. I really want to do a Complete interface that will be as close to Factory as is possible given the difference in vehicle model years. Please Help! I will post a very detailed, and Plug-n-Play writeup for everyone else to use when I am done. Thanks in advance...Also one more thing, I would really appreciate if the replies were limited to real information...not opinions about what YOU think I should do instead. I've seen WAY too many posts turn into B!tch sessions.

[alotawatts]

Another place to try - Lots of folks with know-how at MYE28.com
try a 'ljet to motronic' search

http://www.mye28.com/search.php?mode=results

This is a very good book -

[Mike W.]

I look at it differently, I think of an engine harness and a FI harness. The C101 is of course the engine harness, and I would reuse the one you have, adding or adapting as needed. Most of what it does is things like oil pressure, voltage regulator etc. I'm more familiar with B34/Motronic 1.0 than 1.3, but I think it's pretty similiar. Mostly you will need to power things up, perhaps from what went to the combo or double relay, which is vaguely like the main relay for Motronic. And you pretty much have to use the original connector as I don't think the new one will plug into the fuse box. BTW, you can remove individual wires fairly easily by depressing the locking tab, then sliding them out.

[bimmeup02]

Yeah, the connections at the fusebox are all for powering the (accessories) if you will, but it is finding the diagrams that show which color wire does what, and what socket pin it goes to that is the tough part. As for the connectors, I wrote of my desire to utilize the stock connectors both types to keep it very clean looking, but pulling pins will not help much as the e28 has 17 round pins, and the e12 has 12 flat Blade type connectors...hence the need to make a jumper

[Mike W.]

Well I'm still not sure why you don't want to use the original harness, but there is a way without too much splicing really. Reuse the old connectors. Ah you say, they're crimped on. Yes, but if you really want to got that route, you can cut the wire off the connector, the individual, not the plug, then run a sheet rock screw in there to expand it. It's sharp, it'll bite and go in, then remove the old wires, insert new and crimp. Solder also if you really want it good. You still have to figure out what if anything to do with the extra wires, lets see, a couple for the oil level sensor, and what else I'm not sure offhand, but that is an option.

[bimmeup02]

I'm not sure that I'm following your intent? I plan to use the Original Harness that wires the e28 M30B34 engine...not the original harness from the 3.3L Ljet motor that was in there to begin with. I am upgrading the engine size AND the Injection not just stuffing a bigger motor in it, as I explained in my original post.

[Mike W.]

C101 mostly runs the the conventional stuff any car would have, even carburated ones. Oil pressure, water temp, alternator light, that sort of thing. There may be a couple of wires that interface, but the Motronic harness is very much seperate, so you could use your existing C101 with the motronic harness. Two different harnesses. That's what I mean by an engine harness and a FI harness. Motronic doesn't care about oil pressure or engine gauge temp, it's got it's own FI temp sensor and doesn't use the gauge input.

[bimmeup02]

Thanks, I do understand the difference in the harnesses, but the C101 is where the entire Engine/FI harness plugs into the vehicle, and where the FI harness gets its power. So, through the C101 is where the senders, the ignition cranking and running, combo relay etc. interface with the car. I know that I could make the car run with 4 wires connected, but I want Everything hooked up correctly. thus the need for the wiring diagrams between the e12 and e28 C101 connectors. As I wrote, there is enough information readily available to get 8 of the wire connected, but I still have a few the I need to find a home for.

[Mike W.]

No, motronic gets power directly from the battery, it goes from there to the main relay. Check out the pic. I can email you an E28 wiring diagram if you need or you can find it on Mye28.

[bimmeup02]

Thanks for the reply, I do believe that I have that diagram as part of a ETM download link from a different post. I have been able to find a few e28 and e34 interface diagrams that contain the pinouts of the e28 C101 connector, now I just need to find a 12 pin e12 connector pinout diagram, I can get pretty close with the 8 pin one from the FAQ's but there's still 4 pins that I need to trace down. When I get this done, I am going to post a One-Stop-Shop diagram for any other converters out there to use.

[garethashenden]

There is someone on ebay selling full color e12 wiring diagrams. I haven't gotten one yet, so I can't speak to the quality. I am just arriving at this stage in my own swap.

[bimmeup02]

Ok, I will change the question that I have to...Does anyone know the pinout of the e12 5/6er with the M30 motor C101 connector that is ON THE FUSEBOX? This connector has provisions for 12 pins (blades) but there's only 10 used. I will list the wire colors and their associated position as if you were Looking At the fusebox with the e12 harness plug in your hand starting with the 1.Top Left/Aft and working down as numbered on the plug, and to the right of the list is what I've been able to gather they go to.

1. Brown / Green (Oil Pressure?)
2. Brown / White (Coolant Temp?)
3. EMPTY
4. EMPTY
5. Blue / Violet (Oil Level?)
6. Black / Yellow (2 wires) (Starter)

Top Right/Fwd
7. Green (Coil Positive)
8. Green / Yellow
9. Green / Violet (Fuel Pump?)
10. Black (two wires) (Tach)
11. Brown / Violet
12. Blue (Generator light)

A lot of this is best guess, if I can definitively label each one of these then I should be able to figure the rest out by using the M30B35 diagrams that I've found. However, since there are so many differences and omissions between the harnesses, I know there will be some that just wind up getting re-purposed. Please feel free to write with any info that you have.