M42 Engine wiring issues
 

Ok guys this is my first post as i have been able to find most of what i have needed in the past here without asking for help however in this case i really need some direction. I bought a 1995 318ti that was non-running (its my hobby to build these m44 m42 engines out and make them run, i have a z3 1996 that i have rebuilt from the ground up with minimal issues doing so thus far) the issues i am having is the engine wiring harness on the M42 this is slightly different from the M44 and i do not have a visual reference to which plug goes to which connector/sensor on the engine, on the m44 there is little room for error as the wiring harness has a quick disconnect at the air intake manifold and thus is easily reconnected and disconnected when removing the air intake manifold, unfortunately the wiring harness was disconnected at the time i claimed this car and i have no way of knowing what lead goes where. That being said i have identified the 4 connectors and how they plug to the wiring harness for the cam & and knock sensors in the proper locations however there are several i do not have a way of identifying the following connectors are on the engine but how do i ID the proper connector on the wiring harness for that sensor ? there is an oil sensor under the oil filter, an air intake control plug a throttle body control plug and 2 sensors located on the head under the air intake manifold i believe one is a temp sensor. any visual reference of the wiring harness with plug listings would be great.

Suggest taking a few pics of the connectors in question and posting. I'll cross check them on my 95 M42. :cool:

http://static.bmwfans.info/images/epc/MTY0Ml9w.png

in the image above the connectors in question are the ones coming of the assembly under 5/6

Took a quick look at a M42 I have on a stand, uncaffinated and just before getting ready for work. :rolleyes:

http://i402.photobucket.com/albums/p...psvtnzzots.jpg
http://i402.photobucket.com/albums/p...ps4mlzzodz.jpg

Nothing definitive at this point, I need to untiewrap the harness to get a better view. I'll need to do that tonight after work. Prolly easier to trace the harness on this motor than crawling under Wifie's 95. Config of the harness on this one might look a little different due to the DASC, but the connections should still be there nonetheless.

This M42 harness doesn't have the lower junction box on it. It was all separated by the PO when the DASC was installed for a little more room and installation ease.

A couple of guesses out of that junction. Air temp to airbox. AFM, TPS, 2 knock sensors, CPS. :cool:

Wonderful! At least I have some references, I will take pics tonight of the actual connectors with markers so that we can get a map then I'll put a post up of the final solution once we get the mess figured out, thank you so much for the help

Ok here are more visual references to my issue to make it more clear.


what plugs go to these sensors & how to identify the proper connector from the wiring harness ?
http://i339.photobucket.com/albums/n...M42sensors.jpg

next is this

plug definitions
http://repairguide.autozone.com/znet...528004a13c.gif

and the last misunderstood plug is this

which plug from the wiring harness goes to the DISA solenoid
http://www.bmwe36blog.com/wp-content...disa-valve.jpg

see if that gets you a little more context to work against. :biggrin:

Since you mentioned it how do you like the DASC ?

M42 Engine wiring issues
 

First, I believe the connectors are uniquely keyed, so they should only plug in where the are supposed to go. Check that the rubber seal is still in each harness connector or socket as they sometimes fall out. Water restiance.

As far as the DASC, I suppose I should get one of the two actually installed to give good feedback. I've been focused on getting the target car, my M44 98' Cali solidified first before I put in that SC.

For the M42, I'm just waiting for my Wife to toast her current M42 as a reason to do the M42/DASC swap. It is built and ready to be installed. Unfortunately, I have got that legacy M42 running pretty solid, so it might be awhile. I have a 318ic I have wondered if it should go there. That would raise the fun factor for the Vert.

Too many car and boat projects to get to either mod so quickly.


Sent from my iPhone using Tapatalk

yeah ill be able to verify the plugs later tonight when i get to the house.
thanks for all the help.

ok for anyone who has this problem i found a diagram :)

http://workshop-manuals.com/bmw/3_Se...age-995001.png

1 Switch-over valve for DISA (differentiated suction unit)
2 Switch for reversing lights
3 Starter, terminal 50 (M 6)
4 Starter, terminal 30h (M 5)
5 Starter, terminal 30 (M 8)
6 Alternator D +
7 Alternator B +
8 Remote thermometer sensor
9 DME coolant-temperature sensor
10 Oil-pressure switch
11 Camshaft sensor
12 Crankshaft senso