NEED HELP! 87' M20B27 swap into 89' 325i wiring

[MaschinentechnikerMurdo]

So, after beating my face against hard objects for the last day and a half, i have finally admitted that i need help getting the final stages of my swap done. I have a 1989 325i, the engine decided to give up the ghost so i picked a "new" one off the local craigslist with an ECU for $300. it has an 87' casting on the block and the ecu is a 027. i have the engine and trans completely done and bolted in and i started on the wiring but the loom doesnt seem like it is a direct swap as most of the forums suggest. i have the c101 plugged in and the ecu plugged in, starter is all hooked up (against my instinct both black and red wires are hooked to the big terminal according to forum and pictures, small wire on solenoid 12v signal post) and the engine ground wire is on. yet still, for some reason, the engine will not crank at all. my thinking is that in the process i have somewhere forgotten a ground or a connector somewhere that i didnt know about on the new loom. if anyone has done an older model b20 into a newer model chasis, PLEASE ADVISE!!!

also, if i cannot get this harness to work for some reason, is it possible to run the 87eta motor off my 89i harness and ecu? the only reason i can think of not to try that as a last ditch effort is because i would have to swap the "harmonic balancer" if you want to call it that to account for the 2 different types of crank triggering from what i can tell. aside from that, it seems like the engine would just run a little lean off the i ecu because of the displacement difference. thoughts/advice needed!!!!

[jayuuey]

you would need to swap all the sensors from I motor to your "new" ETA motor. since you already bolted the eta in, you might want to consider a 327i if your old I head is still good. that would be the best possible outcome for you in this case.

basically do this, but backwards.

http://www.r3vlimited.com/board/showthread.php?t=100939

[MaschinentechnikerMurdo]

So is my eta harness and sensors on the engine currently unusable?

[jayuuey]

if you already have all the e sensors on and harness done, you probably have issues with your c104. what did you do with the harness branching of the ecu plug in the glove box? you may not be getting power to your ecu if its not hooked up.

[MaschinentechnikerMurdo]

To my understanding the c104 is the main bus terminal connecting to the ecu, correct? In that case, it is mated directly to the ecu with the exception of one strange looking 3 pin connector that is separate and 2 small white connectors. But I am currently running the ecu that was originally mated to this engine from the factory (027 ecu) I took off the the I ecu that was on there. So theoretically if the c101 is pinned properly and those other little connectors are for unecessary sensors or functions like rpm and evap, I should be good no?