m30 wiring issue

[randomdave325]

hey all. this isn't exactly e30 but i know a few of u have put m30 lumps in e30's so hopefully will have sorted this.
the problem i've got is the e34 i took my m50 from now has a 3.0 m30 in it's place. all is together but atm i have no spark or injector pulse. i wired the r101 plug as per the usual m20-m50 wiring setup so i don't think theres any probs there. what i do have is on the m30 loom there is a small white plug near the ecu which has nowhere to go on this car.
i'm getting a live feed and a pulse feed from 2 of the pins. obviously this needs to go somewhere or be bypassed somehow to make it start.
this is the plug.





the wire colours on the engine loom plug are red (12v live), grey/black (pulsed live), black/white(?)and black/blue.

the wire colours on the original cars loom are red, green/ black, black/white and purple/ green.

the car that it's in now is a 94 525 and the donor was a 89 530 if it helps

hopefully someone will have come across this before as e30's don't have this plug either.

it started as one of those quick favours for a m8 and is now doin my head in. please help!

[Brianmoooore]

There's a similar plug near the ECU on E30s. It's only normally used on cars with aircon or switchable autos etc. Don't think its relevant to your problem.
Have you connected all the reds at the battery, and earthed all the browns and brown/orange?
Check for 12V+ at the red wire on the main DME relay, and for ignition 12V+ on the coil + terminal.

[randomdave325]

thanks brian. i know the plugs u mean on e30's. this has them 2! i don't think they are connected to this plug tho. the original car had this plug and is a manual with no a/c and it was connected. i've cut the loom back and traced it on the 530 (much fun) and the red goes to a huge chunk of reds under the fuse box. as does the green and black. the black/ white goes to a load of black/ whites in the relay box on the n/s inner wing. these are all the ones with the yellow caps on. u know the ones. and the purple/green goes to one of the relays in that box. but the m50 car doesn't have this.
someone must have bypassed this on an e30.
all the lives and earths are on and in the right place m8.
come on you 3.5 boys. where u at??

[ed325i]

Have you got these plugs the rigth way round ? the crank sensor goes to the left one.

ED

[randomdave325]

Have you got these plugs the rigth way round ? the crank sensor goes to the left one.

good thinkin that man but i didn't disconnect it as took the whole loom with the engine so didn't need to touch that. i have since changed the crank sensor cos it is that kinda prob but still no joy. it was running when it came out. thats what makes it so annoying. i'm pretty sure it is all down to this plug. liking the ideas tho people. keep em comin. thanks

[ed325i]

Have you got it going ??

ED

[randomdave325]

Have you got it going ??

hiya. in a word. err no!! i've had no time to play with it today but i did check if the plugs were the right way round. which they were god dam it. i had an interesting conversation with someone who put a later engine in a 635 and they had similar problems which all came back to this one white plug. but annoyingly he couldn't remember what it was he did to it to get it going as was a couple of years ago and he doesn't have it anymore .
in some ways i wish i hadn't spoke to him as it just made it more annoying.
i'll have another play tommorrow and keep u posted.i'll double check the big multiplug wiring again but just wired it pin to pin as i did the m50 wiring on mine so it really should work. they should be the same.
unless anyone knows otherwise???
thanks for asking tho. it will run eventually!! i've spent too long on it now to give up

[ed325i]

I just pluged the big round plug in but I have no rev counter or ign light

ED

[randomdave325]

i used this for the wiring m8 which brianmooore kindly supplied when i was fitting my m50 to the original shed. 13 months, 11000 miles and a reshell ago. doesn't time fly hey

E34 M50 Tu E30

1/ blue/white (oil level, dynamic) 2/ green/yellow
2/ blue/yellow(oil level static) 10/ blue
3/ red/white (ABS supply) 20/ red/yellow
4/ black/blue (aircon)
5/ black/grey (aircon)
6/ purple/grey (aircon)
7/ black/purple (drive away sigle for E34 OBC)
8/ grey (engine fault) 12/ grey
9/ NC
10/ NC
11/ brown/yellow (water temp)
12/ brown/purple (water temp) 4/ brown/purple
13/ green/purple (fuel pump) 13/ green/purple
14/ black/white (speed to inst. cluster) 14/ black/white
15/ black/green (unloader relay) 15/ black/green
16/ white/yellow (Rx data)
17/ white/purple (Tx data)
18/ black/yellow (starter) 18/ black/yellow
19/ white/green (SI. reset) 11/ white/green
20/ black (engine speed to cluster) 9/ black
21/ Green (ignition) 7/ green
22/ green/white 6/ green/white
23/ brown/grey (oil pressure) 5/ brown/green
24/ white/black ( fuel rate to cluster) 8/ white black
25/ blue (ignition light) 1/ blue.
.
from this on an e30 pin 1 is ign light and pin 9 is tacho.
hope this helps

[randomdave325]

actually thinking about it i never asked it the m30 plug goes straight on to the m20 plug (r101) i just kinda assumed that it did. does anyone know or have the pin data for the e34 m30? brian again perhaps maybe please??

[Brianmoooore]

actually thinking about it i never asked it the m30 plug goes straight on to the m20 plug (r101) i just kinda assumed that it did. does anyone know or have the pin data for the e34 m30? brian again perhaps maybe please??

AFAIK, the only issue is the lack of the black/green unloader relay "earthing" wire to the starter motor in the M30 engine loom

[Brianmoooore]

The engines with their associated looms and ECUs are all fairly well self contained on all these engines.
Apart from the red(s) to battery pos., and the browns and brown/oranges to battery neg. direct from the engine looms, the only C101 connections essential to the engine running are the green ignition wire and the green/purple fuel pump wire (+ the black/yellow starter wire to get it running).
Everything else is just for accessories or instrumentation.

[randomdave325]

interesting. i'd imagine the wire to the starter is there as i didn't touch any of that. there is a green/black on that plug. i'm sure thats the one that pulses. am i right in thinking this goes to earth then? it's just pulsing as the negative side of a coil would with a set of points and is probably the trigger to tell the ecu the engine is turning??

[Toby_Unna]

did the m30 run in the original car?!

if you can get a positive feed to the fuel pump to run it, all the engine needs to run is a positive feed direct to one of the coil terminals and then touch a positive wire to the starter solenoid, don't even need the c101 connected.

if that doesn't work there's something wrong.

[Brianmoooore]

did the m30 run in the original car?!

if you can get a positive feed to the fuel pump to run it, all the engine needs to run is a positive feed direct to one of the coil terminals and then touch a positive wire to the starter solenoid, don't even need the c101 connected.

if that doesn't work there's something wrong.

This is all correct. The pos feed to the fuel pump bypasses the green/purple in my post, and the pos feed to coil + bypasses the green wire.
The black/green wire from the E34 body loom should read a steady 12v+ when not connected to anything and measured with a meter, with the ignition on. Earthing this wire should make a relay click.

[randomdave325]

kool thanks guys. there is definatly 12v at the coil. the black green wire only has voltage when cranking. it pulses on and off so reads about 8v averaged when measured with a meter. fuel relay is not running but even with no fuel it should spark. should i just earth the black/green then?

[Brianmoooore]

kool thanks guys. there is definatly 12v at the coil. the black green wire only has voltage when cranking. it pulses on and off so reads about 8v averaged when measured with a meter. fuel relay is not running but even with no fuel it should spark. should i just earth the black/green then?

I've never worked on a M30 loom, but from other previous postsin other threads, the M30 loom doesn't have the black/green wire. It can be connected to the short link between the starter solenoid and the starter motor body, or , as a less satisfactory alternative, can simply be earthed.
If the coil has power, you hot wire the fuel pump, and the red wire at the main ECU solenoid has power, then the engine should run.
If there's no spark and the fuel pump relay doesn't pull in, then check out the crank position sensor and its wiring.

[ed325i]

Hi, Have you got it going yet??
ED