bmwe21.net forums

Fingers crossed she fires up ok mate. One thing though - check your earths.

This is a great build thread, love being able to logon each day and see the progress, almost as good as being there!
Don't stop the thread once the engine is complete and running as I suspect that you will be modifying the running gear etc and I would love to see further developments.

I'm in the process of connecting all the wires up, i have everything connected BUT the GREEN/GREEN ignition switch to motronic #27 as there seem to be no more spare green wires in the motronic plug.

Quote:
from bmwe21.net.techincal

E21 Plug # E21 Wire color Motronic 1.3 Wire color Purpose

1 Brown/Green Brown/Green Oil pressure switch to instrument cluster
3 Green/Black Green/Violet & Black/Green Power to Fuel pump from Fuel pump relay and starter
5 Blue Blue Alternator Charge (D+) to instrument cluster
6 Green/Violet Green Coil 15+ / O2 Sensor Heater Relay

8 Green Green ignition switch to Motronic #27<------this one, what green wire??
There were two green wires, one thin one fat on the male side of the plug both coming out of pin#7 which is used for the ign coil/heater relay

10 Black Yellow/Black ignition switch (start) to starter
13 Brown/White Brown/Violet from injector rail (temp sensor) to instrument cluster
15 Black Black from Motronic #6 to tachometer


I'm on the cusp of firing this thing up but i don't want to damage anything.

Everything else is wired up ready to go....

I went back out to the shed to have a crack at the car.

It cranks over, it has fuel pressure, the gauges spring to life when the ignition is turned on.

I have a solid green wire coming from the engine plug in the fuse box that is live when the ignition is on, logic would dictate that it should go somewhere on the motronic harness.

I can see pin #27 on the ECU but i will have to start testing the harness to find which wire in the loom makes it live.




Its all quite untidy right now but once the engine fires i can go and do it all properly.

Oh and the oil cooler is reconnected, zip tied to the two towing eyes, i should have taken a pic.

Getting close now!

Mind my language for that second if you please, but f*** hell varden, what have you done? you`ve mullard the engine harness dude, all you need to do is connect a few wires without the hassel, tell me what wiring loom did you use, from what bmw model??


J

hi ALPINA

The loom came out of a 3/1989 325i E30 AUTO.

Any help solving this mystery would be greatly appreciated.

I'm still researching and I'm finding reference to an inhibitor switch circuit in an 89 e34 M30 auto loom that will prevent a car with an e34 auto loom from starting, will this apply to me and my 1.3 motronic auto loom?

Without going thru the post, what exactly is it your trying to do... to the point?



J

notes from my thread......

well ive got no diagrams but this is what i have!
right....... on the car side of the motronic loom i have;
1) solid blue
2)blue/black
3)-
4)brown/pink
5)black/brown
6)green/yellow
7)solid green
8)yellow/white
9)solid black
10)pink/green
11)white
12)-
13)violet/red
14)blue/yellow
15)black/green
16)-
17)-
18)black/yellow
19)-
20)red/yellow

on the e21 loom i have these pins:
3x green/violet..... ing lives..... wire to bits on the carb.
2x big greens...... ing lives...... 1 of which was live side of e21 coil.
2x blacks...... one went to coil neg, one went to the tci unit.
2x blues...... ing lives...... alternator.
1x brown/green....... ing live...... oil light switch.
1x brown white.......... water temp.

ones ive figured out;
starter soleniod.................big black - black/yellow on pin 18 of c101
alternator exc. wire...........solid blue - solid blue on pin 1 of c101
oil light switch...................brown/green - black/brown on pin 5 of c101
water temp.......................brown/white - brown/pink on pin 4 of c101


when id worked them out......

wiring is simple really.....
on mine....
from the e21 engine loom plug to the c101 round plug on the motronic loom.
- ing. feed to the coil - green/violet to solid green, pin 7
- starter solenoid - big black to black/yellow, pin 18
- rev counter - smaller black (different pin to starter wire) to solid black, pin 9
- alternator exc. - solid blue to solid blue, pin 1
- oil light switch - brown/green to black/brown, pin 5
- water temp. - brown/white to brown/pink, pin 4
- fuel pump is simply earthed and fed live via the violet/red, pin 13 (id suggest putting an in line fuse in this just as it comes out of the c101 connector.
the rest of the wires separate from the c101 are black sheethed wires grouped together with ring terminals on. brown/violet and solid brown both need earthing.
and 4 reds same deal need battery live.

have a nosey at what i did. jimi posted some useful links in my thread too.
http://www.bmwe21.net/forum/viewtopic.p ... c&start=15

ALPINA wrote:
Without going thru the post, what exactly is it your trying to do... to the point?

I'm using the wiring chart at http://www.e21bmw.net/tech/motronic.php and cross referencing it against Murrans chart on his conversion thread cos he has added in the motronic pin outs to his chart for added clarity.

My goal here is to get this 325i engine and auto loom up and running in my manual e21 323i, but the chart at http://www.e21bmw.net/tech/motronic.php calls for me to connect the green e21 ignition lead to the green ign lead to motronic pin #27.

But after i connect the green/violet e21 lead to the available green motronic lead at plug pin #7 as specified I'm all out of green motronic leads.

Unless the green/violet AND the solid green e21 ign lead connect up to the green motronic lead, but I'm reluctant to try that cos there is a fluctuating voltage signal on the green/violet e21 wire and a solid ign signal on the green e21 wire.

I've already swapped out the green/violet wire and connected the solid green 21 ign to the motronic solid green as per murrans thread at http://www.e30zone.net/modules.php?name ... c&t=107543 but i didn't help.

Brianmoooore wrote
The live feed to the fuel pump comes from the purple/red on pin 13 of the motronic loom. Connect it to the red of the fuel pump via a 7.5 amp fuse.
The ECU lives all come from the main battery + connection on the motronic loom. A thick red wire (may be under a black sleeve), that is nothing to do with the C101. The main loom earth will be near it, which is a brown or brown/orange wire which also may be under a black sleeve.

The two big greens on the E21 loom go to the E30 green on pin 7. This is the ignition feed to the coil, and also switches the ECU on and triggers the main DME relay (white one).

That's all you need to connect extra to get the engine to run.
Rest of the M20 loom:
2 and 10 are oil level sensor.
6 should be fed a 7.5 amp fused ignition live. It connects power to the data receive pin of the motronic ECU when the cap is on the diagnostic socket, although I don't know what the long term effects of this supply being missing are, if any. It also supplies power to the relay for the lambda sensor, if for any reason you need to use it.
8 is the fuel rate signal from the ECU to an E30 instrument cluster.
9 is the engine speed signal (rev counter) from the ECU to an E30 instrument cluster. I doubt if it will drive the E21 tacho.
11 is the wire from the diagnostic socket that resets the service indicator lights in an E30 cluster.
14 is a road speed signal going to the ECU from the E30 cluster. I doubt if you'll find a suitable signal on an E21.
15 is the connection to the starter motor that switches the unloader relays i an E30 fusebox. Not relevant to E21s.
20 is the feed from the motronic loom to the ABS system.

Tho as i look at murrans engine plug pic it looks like the two green ign lives aren't used.

murran wrote:

http://i200.photobucket.com/albums/aa91 ... wap007.jpg

wiring is simple really.....
on mine....
from the e21 engine loom plug to the c101 round plug on the motronic loom.
- ing. feed to the coil - green/violet to solid green, pin 7

- starter solenoid - big black to black/yellow, pin 18

- rev counter - smaller black (different pin to starter wire) to solid black, pin 9

- alternator exc. - solid blue to solid blue, pin 1

- oil light switch - brown/green to black/brown, pin 5

- water temp. - brown/white to brown/pink, pin 4

- fuel pump is simply earthed and fed live via the violet/red, pin 13 (id suggest putting an in line fuse in this just as it comes out of the c101 connector.

the rest of the wires separate from the c101 are black sheethed wires grouped together with ring terminals on. brown/violet and solid brown both need earthing.

and 4 reds same deal need battery live.

There is something I'm missing here....but i don't know what.

murrans chart is spot on but it looks like he didn't need to use the green 21 ign going by his pic and his chart.

some e30 wiring looms are not always the same colours from what ive expericanced, you do get some with different colours which means you have to match all wires from the chart to what you have and the one thats different to whats yours on your wiring loom then its that wire that needs to be connected.


Hope this makes sence..


J

Yeah i think your right ALPINA.

Tomorrow I'm going to map the ecu plug out to see what pins correspond to what wire colours cos there are differences between my motronic loom and the pics of murrans loom.

The pin outs should be uniform even if the wire codes are not.

dunno if it helps but my loom was from a '89 "f" registered e30 320i manual 2 door with abs.
found it exactly the same as my '90 e30 touring 320i that i put a 325i into using the same loom.

http://i200.photobucket.com/albums/aa91 ... wap003.jpg

this pic has a close up of the e21 plug loom plug the wires cut short, i didnt use!

the c101 round plug....

http://i200.photobucket.com/albums/aa91 ... wap006.jpg

Hi varden,
awesome thread, am realy enyoing it and wish i could help with the wirring trouble..

but on a compleetly different note do you have any plans with your old engine, or head ?
Thanks mick