help! Swap cranks but no start

[Andrew325is]

Also, I included details in the instructions I provided for the back-up lights connector. You can use either the E30's old back-up lights switch connector or the one on the S54 transmission/oxygen sensor harness if you wire the E30 wires to the X6021 connector on the adapter harness, pins 3 and 4. Make sure that harness section is from a manual trans car, not SMG.

[Andrew325is]

That blue relay is the DME relay. The Brown/white wire (pin 4) connects to the X60002 connector pin 23. The X60002 connector is the second DME connector. It's the one with 24 pins. That's the activation signal for the relay, so if you connect that hopefully that'll fix you up. :)

[diesekte]

A little background: I bought my car (89 325IS) with an M52 in it, with a conversion harness from C101. Two questions I have in that regard are: 1) I don't seem to have a "main relay"- the area where three relays are supposed to sit has an aftermarket fan relay placed by previous owner for electric fan. Could no main relay be related to this issue or no? 2) never hooked up, even with M52 swap, coming off fuse box, what is this?



I went back and pulled everything back out from the firewall into the engine bay and started from the beginning.

This is still unhooked - I'm guessing it doesn't matter? One red/white stripe/yellow dot wire, one brown/yellow stripe wire


No clue where these go. My guess is trans, but can't I just use the E30 connect for reverse lights? If I use the E30 one, there are two places it could go - it goes on the one closer to engine or closer to rear?


I was tracing the wires, and came upon this relay


This brown/white stripe wire coming from it is totally broken off, with no hints as to what it is supposed to connect to. If I apply this broken wire to ground, the fuel pump primes, but still no start :/.


This is my junction. The top (thin black wire from battery) has what appears to me to be the 2 power inputs to the ECU connected to it. The yellow wire is the wire from andrew's harness that goes to e46 m3 fuel pump relay. To the right of that I have connected the thick cable that goes to the starter, as well as the "Y" shaped cable coming off the fuse box


I know its hard to tell what's going on here, but here's a pic of how things are now for reference. I can email a higher res/larger pic if needed:





TLDR: I found a broken wire (but only one end!) that when put to ground causes the fuel pump to run when key in "on" but still no start. I didn't have time to get my cable and computer today to run INPA, but I highly suspect my ECU is not getting power or is not grounded properly.

Is there any noise that should come from the ECU if its on? Faint hum etc? Should pushing the throttle pedal down, even with key in "on" cause the throttle bodies to open? I don't get any activity.

The way Andrew's harness is, things are more or less straightforward. I mean when combing the various e46 m3 harness and his harness, things really only go one way....I'm not sure what is stopping ECU from having power, it all seems connected correctly to me

[gpeterson]

Yes it was. Also I was under the impression it wouldn't even turn over if EWS wasn't deleted?

It will. EWS on the DME side cuts fuel/spark and the EWS module cuts the starter. I'm guessing you have no EWS module installed.

[diesekte]

EWS deleted from your DME?

Yes it was. Also I was under the impression it wouldn't even turn over if EWS wasn't deleted?

[gpeterson]

Thanks, will lay everything out and look at it again. I have INPA and a cable but no dedicated obd2 hand held scan tool. That way I should be able to at least see if dme has power.

Yes, fire up INPA to see if it communicates at all and check codes. Was EWS deleted from your DME?

Another odd thing...I can't seem to find EKP. What is it supposed to be connected to?

EKP = PWM (variable speed) controller for fuel pump. It isn't necessary and isn't present on euro models. MSS54 with a US tune will still drive a regular fuel pump relay via X60004 pin 10. Running a US tune with no EKP will cause a code to be stored unless coded out.

I do have 1 plug I can't find the other end of by the ecu. It is a white 3 prong plug with 2 female pins in it, 1 connected to a brown/yellow stripe wire, and rhe other 1 to a red/white stripe wire

Probably the e-box cooling fan, not necessary but will cause a code to be stored unless coded out.

[diesekte]

Thanks, will lay everything out and look at it again. I have INPA and a cable but no dedicated obd2 hand held scan tool. That way I should be able to at least see if dme has power.
I can't seem to find any wiring diagrams for the e46 stuff though. Links are all dead or not very informative. It would be nice to have the schematics with wire color labeled for all the connectors etc so I am 100% I've got everything connected properly.
Another odd thing...I can't seem to find EKP. What is it supposed to be connected to?
I do have 1 plug I can't find the other end of by the ecu. It is a white 3 prong plug with 2 female pins in it, 1 connected to a brown/yellow stripe wire, and rhe other 1 to a red/white stripe wire

[DesertBMW]

When I have problem like this, I hook up my snap on scanner, that can do any BMW 88+. Then if the scan tool can't communicate with the ECU then I know ECU is not getting power. If I can get into diagnostics then I can activate components and do the test like that. Problem can be narrowed down with a good scan tool. Without it just becomes big guess game

[diesekte]

I'm using Andrew's wiring harness. When it comes to electrical stuff/troubleshooting I am totally confused by everything, so keep it simple for my sake.
Swap cranks up no issue, but won't start...
Didn't think I heard fuel pump working, so I pulled the back seat and lo and behold, it wasn't doing anything (pump is new - TRE walbro 255 equivalent).
I jumped the fuel pump relay between pins 6 and 2 and the pump stays on regardless of key position and primes the system as it should. Put fuel pump relay back in (brand new btw) and nothing. Try another relay, nothing.
Tried to start car with the pump jumpered, and it still won't start.
Pulled fuse 11 and it looked fine. Tested with test light and didn't seem to be getting power through fuse 11.
This seems to be a common problem post swap on E30s and every thread I've seen about it seems to have a different answer. Not sure why it worked with my M52, but all of a sudden now things aren't working as they should. The E30 body side C101 has remained untampered with, so this doesn't make any sense to me

Appreciate any advice, would REALLY like to get running (by)this weekend.