pin 7 and pin 21 what's the deal with two wires in one? I got no signal to fuel relay

[singh336]

E30 = 1990 325i

M50 = 1992 325i M50 Non vanos

Harness = Automatic M50 Harness and ecu that came with it.

I tried my best to safely strip off automatic wiring from the harness but probably left some of it in there.



My issue is, car cranks of course, but no start.


NOT getting fuel , jumped relay socket for the M50's fuel pump relay and it pours out fuel no problem...

Tested for voltage / signal to relay socket when cranking the car and I got nothing.....


my grounds are on the engine, diag connector, then the positive near the diag connector is on the pos block off firewall, and the only other positive is to the starter off the firewall.


Basically I'm not getting signal from DME to start fuel pump so i've got some figuring out to do...

I want to check wiring first and test crank sensor after because the engine was running in the e36 it came out of

[singh336]

I've heard some people saying to check the ignition switch to dme wires, because on the M50 harness side there is two wires that come together, which both need to be connected to the pin 7 on the m20 side ?

[singh336]

I just noticed my check engine light does not come on when turning the key to the on position

I'll be uploading pics soon to show my grounds and wiring and tomorrow I'll pull the intake an inspect the crank sensor if need be


how can I test for power at ecu what pin numbers etc ?

[hwy84]

If you have no CEL, you have no power to the ECU.

Did you do your own harness? If you post your conversion, we might be able to see what's gone wrong.

Check all your grounds - block to chassis, injector harness to engine lift bracket on head, coil grounds (2 - but they won't be the problem here), and harness to strut tower.

If those are good - check your positive lines - sounds like you have the starter hooked up right, but how is your alternator wired? What about the harness positive cables?

You probably covered all this - but it can't hurt to double check. My money is on the harness conversion at this point.

[singh336]

hey man, thanks for the reply

okay , as I said in first post it's the harness that was originally with the engine from an auto magic 325i which I cut off the extra connectors for the auto tranny


one ground I didn't hook up because I thought it didn't matter was the fuel rail ground that was broken and I haven't bothered to hook it up, doubt that would give me no cel but I'll def hook that up I just heard it was for noise ground etc

as far as positives all I have is the positive just before the ground on the diag connector and the positive from the dist block to starter

I saw bmw jumps all power for alternator off the starter

[singh336]

my question is how does my engine run with starting fluid if there is no power to the ecu ? because the coils must be firing in order to make spark ? it sounds like every cylinder hits too not just random pops

[singh336]

here's some picture

[singh336]

okay i posted those pics from my phone let me explain..

was trying to show the dash lights when the key is on

then i took some pics to show what i had hooked up to the block on the firewall for hot power

and then i showed my grounds... i grounded (temp of course) the engine hook bolt to the shock tower because my pass control arm is broken where the ground strap is supposed to go, so i'll make something later for that.


then i showed some pics of my iginition wire which i don't see where two wires go into one on either side, i just see two wires further down the harness that won't make a difference if connected at all...


i just need to figure out whats up with no power at ecu..


heres what i got


positive / hot wire hookups...

one to the firewall from diagnostic connector line as seen in the pics

and one to the starter straight from the firewall whcih then jumps to alternator..


for grounds i have

fuel rail, main engine block is grounded and shock tower for diag connector



I feel i might not have enough power leads connected, is there is only two wires for the power that need to be connected?

[singh336]

found out what the problem is

cut the wrong stuff out of my auto tranny harness


need a new harness so...

WTB M50NV WIRING HARNESS