M52 Starting Troubles

[PotatoE30]

Hi Guys,

I am having some starting issues with my M52 swap and hoping you could help me out.

A little background information on the build, the car is a 1989 E30 318i Manual and the M52 is out of a E39 Auto. I'm using a MS41.0 ECU that has had the EWS removed and the usual tune for the M50 manifold etc. I've used several different wiring guides to cross reference the C101 graft as the colors were a little out for certain things (from memory the instrumentation signals etc)

I have replaced the CPS with a genuine BMW part however the cam position sensor is the original unit.

Currently I have no spark at the coils and no pulse to the injectors, i have also found that the main relay is not being triggered by the ECU on ignition, however when applying 12v to pin 87 on the ECU it does activate the relay giving power to the injectors and causing the ICV to hum, unfortunately this still wont enable the car to start.

Ive done quite a bit of digging around and can't seem to get anywhere, i have tried finding the infamous Brown/Black wire which is supposedly located at Pin 27 on the ECU for the auto trans signal but no luck as some others have also found.

I'm thinking to maybe pull the harness back out and re-check all my wiring,
any help would be greatly appreciated, i know I'm posting in the right place to get this thing back on the road again!

Thanks in advance

Bill

[mpowerful]

I know that on my obd2 swap the unloader relay had to be functioning to start despite whatvid read elsewhere.

[PotatoE30]

I know that on my obd2 swap the unloader relay had to be functioning to start despite whatvid read elsewhere.

Will re-check the unloader relay asap, however from memory it was functioning when i was poking around the E30 fuse/relay box with the test light when it first wouldn't start

[mpowerful]

Will re-check the unloader relay asap, however from memory it was functioning when i was poking around the E30 fuse/relay box with the test light when it first wouldn't start

The unloader on an e36 harness is a relay right next to the DME. It needs to be grounded to work.

[PotatoE30]

The unloader on an e36 harness is a relay right next to the DME. It needs to be grounded to work.

I'm using an E39 Harness so the only unloader relay that i've got is the factory E30 relay which is located in the fuse box under the bonnet. Could my issues be stemming from the fact that i am using an E39 harness?

[PotatoE30]

After checking over all my connections again i still can't get this thing started, i am starting to think it is the E39 harness, has anyone used an E39 harness before? or should i be swapping it out for an E36 harness?

Thanks

[Dgerry]

E39 Harness

Hello,

Yes, E39 harnesses have been used, and yes, they are a little more difficult, but can be made to work. Here is a link to a thread with some pinouts even:

http://r3vlimited.com/board/showthread.php?t=402860

Hope this helps you get it started. Post up what you find. Thanks!!

[PotatoE30]

Small Update

Problem Solved!

Just thought I'd update this incase anyone else was having similar issues and stumbled across this thread. The issue was the E39 harness, unfortunately the harness didn't have the extra plugs like dgerry's links talks about, so none of that wiring diagram could be used, I guess it may have something to do with Aussie E39s or something.

The solution was swapping to an E36 (Auto) harness and following the plethora of guides that are already out there, the car fired right up first time and idles beautifully even without a proper intake and exhaust!

Thank you for all your help and suggestions :)