Please proofread my wiring diagram - E30 S52 swap

[Sh3rpak!ng]

I am currently working on the wiring for my s52 swap. I have been doing a lot of research between the etms for both e30 and e36, searching for other's wiring diagrams, reading as many threads discussing wiring as I can find and now I am at the point where I think I just need some advice. I am pretty sure I have figured out most of it, but there are still a couple of connections that I am not sure of.

Basic specs are a 1989 325i manual getting an obd2 s52. I have an ECU with ews, rear O2s, muffler flap, evap, and secondary air pump deleted and with a tune for an m50 manifold. I am rebuilding the motor very slowly and figure while I wait for time/money I will tackle the wiring. The harness is from a 98 m3 manual. I have a spare c101 connector that I plan to splice into the e36 engine harness. (my 2 cars are the e30 325i and an m52 e36, so I will be able to physically reference either car if necessary)

I have prepared the conversion diagram in excel for review. The lines with green x's are the ones I think are good. The ones marked with red I am not sure of.



Here are my diagrams for the x20 and c101 connectors that I did prior to working out the conversion. These diagrams are a combination of what I could figure out from the ETMs, what I actually physically saw and a little from other threads.

[nando]

personally, I like using engine colors for the E30 instead of body side. less variability, and they match up 1:1.

I think some of your wire colors are wrong. red/white wires are power, I'm pretty sure the CEL wire isn't red/white. use the O2 relay pin to power the OBD port, the relay is self contained on the S52 harness.

pin 20 on your car, assuming you have an airbag, is to power the ABS relay. Jump it back to pin 15. if you don't have an airbag, leave it blank.

you don't need to connect pin 16.

yes, you do have to wire in your own sensor wiring for the coolant gage. it's just a single wire, typically brown/purple. you also have to take some wires from the other connector (it's right next to the X20 and looks similar), the OBDII cars don't have everything on the X20. they're a pain in the ass, to be honest.

[Sh3rpak!ng]

personally, I like using engine colors for the E30 instead of body side. less variability, and they match up 1:1.

I think some of your wire colors are wrong. red/white wires are power, I'm pretty sure the CEL wire isn't red/white. use the O2 relay pin to power the OBD port, the relay is self contained on the S52 harness.

pin 20 on your car, assuming you have an airbag, is to power the ABS relay. Jump it back to pin 15. if you don't have an airbag, leave it blank.

you don't need to connect pin 16.

yes, you do have to wire in your own sensor wiring for the coolant gage. it's just a single wire, typically brown/purple. you also have to take some wires from the other connector (it's right next to the X20 and looks similar), the OBDII cars don't have everything on the X20. they're a pain in the ass, to be honest.

Yea, I am sure there are a couple wrong ones. That CEL connection is definitely wrong, however every diagram I found said connect x20 pin 8 to c101 pin 12.

Don't I need power to the ABS relay regardless of if I have an airbag? (I do not have an airbag fyi)

Ok, which pins/wires for the O2 relay to power the OBD port?

Which wires do I need from the other connector next to the x20? (is that connector the x69?)

I know its a bit more of a PITA, but I figured with all the stuff deleted from the DME, especially EWS, it shouldn't be too hard. Plus I got very good deals on the parts.

Thanks so far, keep it coming. I will update the diagram shortly.

[Sh3rpak!ng]

the CEL output is from pin 20 on DME to pin 1 of x6031 (must be the third connector next to x20 and x69) - so I re-route this through the c101? to pin 12?

[nando]

yes. it's not in the X20. on OBD1 cars, it's all in the X20, but BMW decided to move a bunch of wires around (even though there are still empty slots in the X20).

the other wire in there is the econometer

[Sh3rpak!ng]

yes. it's not in the X20. on OBD1 cars, it's all in the X20, but BMW decided to move a bunch of wires around (even though there are still empty slots in the X20).

the other wire in there is the econometer

gotcha. Well, I will not be defeated. I haven't found anything very comprehensive on OBDII wiring, so I hope this helps somebody.

Looks like I need to read the ETMs again haha searching for the x69 and x6031.. see what's connected to them

[Sh3rpak!ng]

Checked the x69, looks like it's all auto trans (egs) related connections

[Sh3rpak!ng]

I will run my multimeter over the e36 relays and x20 connector with the car off, in run and start and see where is getting power and in what positions. I suppose this can help me determine some more definitive answers, and validate my diagram so far.

[Sh3rpak!ng]

Whoops, didn't realize I didn't post this in the M50/52 & S50/52 subforum. I will repost the thread there.

[nando]

I'll just move it.

[Sh3rpak!ng]

I'll just move it.

Thanks! didn't realize you were a mod

[luckysnafu]

SH3 - Your diagram looks pretty good, I agree with nando's suggestions for the temp gauge and CEL. Feel free to reference my diagram for a 1990 325i to 98 Z3M S52

http://www.r3vlimited.com/board/showpost.php?p=4318120&postcount=59

As for the OBD2 port, you need to get the data wire from the diagnostic port Pin 17, which comes from ECU pin 88. The OBD2 port is just 4 wires from that point:

OBD2 Pin
4 - Ground
5 - Ground
7 - Signal (diagnostic port Pin 17)
16 - +12V (switched if you only want the port active while the car is on)

[Sh3rpak!ng]

SH3 - Your diagram looks pretty good, I agree with nando's suggestions for the temp gauge and CEL. Feel free to reference my diagram for a 1990 325i to 98 Z3M S52

http://www.r3vlimited.com/board/showpost.php?p=4318120&postcount=59

As for the OBD2 port, you need to get the data wire from the diagnostic port Pin 17, which comes from ECU pin 88. The OBD2 port is just 4 wires from that point:

OBD2 Pin
4 - Ground
5 - Ground
7 - Signal (diagnostic port Pin 17)
16 - +12V (switched if you only want the port active while the car is on)

Just to clear up - which ports are you referring to when you say OBD2 port and diagnostic port? (OBD2 port - under the driver dash on an e36? diagnostic port - the circular "port" under the hood next to SAP?)
^want to make sure I understand correctly

And you are saying I need to run a "new" wire from diagnostic port pin 17 to OBD2 port pin 7? or does this wire already exist, I just need to relocate it?

I am sure this will make more sense if I had the harness in front of me. I'll take a look at it tonight to refresh my memory.

[Sh3rpak!ng]

Feel free to reference my diagram for a 1990 325i to 98 Z3M S52

http://www.r3vlimited.com/board/showpost.php?p=4318120&postcount=59

Yes, I already have this printed on my desk from the other thread on OBD2 wiring for e30. Great info, thanks!

[luckysnafu]

Just to clear up - which ports are you referring to when you say OBD2 port and diagnostic port? (OBD2 port - under the driver dash on an e36? diagnostic port - the circular "port" under the hood next to SAP?)
^want to make sure I understand correctly

And you are saying I need to run a "new" wire from diagnostic port pin 17 to OBD2 port pin 7? or does this wire already exist, I just need to relocate it?

I am sure this will make more sense if I had the harness in front of me. I'll take a look at it tonight to refresh my memory.

When I say OBD2 port I'm talking about the port under the dash on an e36 that you can hook up to an OBD2 reader/bluetooth adapter.

No, you don't need to run a new wire from the round diagnostic port, you just need to tap into pin 17 to get the signal for the OBD2 port. On my cars I actually got rid of the round diagnostic port because it takes up too much room and just use the OBD2 port for diagnostics.

Hope this makes sense.