Please proofread my wiring diagram - E30 S52 swap

[jjc034]

So I am having an issues with my ms41.1 swapped car where the round diagnostic port will power my obd2 scanner but no connection can be made. I linked c101 pin 6 to x20 pin 22 for switched power, c101 pin 12 to x20 pin 1 for CEL, and c101 pin 16 to x20 pin 17.

Does anyone have any clue why it won't communicate? Did I miss a wire connection? Pin 16 on X20 is currently not connected to anything.

Another member said to splice something into pin 17 on obd connector, but I'm not sure about that.

Any help is greatly appreciated!

Thanks,
John

Sent from my SM-G930V using Tapatalk

[Sh3rpak!ng]

you don't need to rout it anywhere, you just pop the hood and use the port right there. the main advantage of the OBD2 port is you can more easily log while driving or something, but on the E36 motors they just aren't that advanced that it would really matter.

you'd be able to write to it just the same as long as the k-line is hooked up.

Sorry, yes I get what you are saying. I actually have an adapter already

[nando]

you don't need to rout it anywhere, you just pop the hood and use the port right there. the main advantage of the OBD2 port is you can more easily log while driving or something, but on the E36 motors they just aren't that advanced that it would really matter.

you'd be able to write to it just the same as long as the k-line is hooked up.

[Sh3rpak!ng]

you don't really need the OBD2 style port, you can just use the existing OBD port and get a 20 pin adapter for like $5.

I like that idea. And just route the port into the cabin under the dash somewhere?

What about retaining the "write" capability? Or would that be retained because I just use an adapter?

[nando]

you don't really need the OBD2 style port, you can just use the existing OBD port and get a 20 pin adapter for like $5.

[Sh3rpak!ng]

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.

Yes this makes more sense. I am thinking this means I need to go to the junkyard and get the "OBD2 port harness" aka the physical port + wires?

Yea, I was thinking about getting rid of it too. But isn't the diagnostic port the one that has the "write" capability to the ecu? SO if I wanted to flash a tune onto the ecu I would need that round diagnostic port?

[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.

[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!

[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.

[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]

I'll just move it.

Thanks! didn't realize you were a mod

[nando]

I'll just move it.

[Sh3rpak!ng]

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

[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]

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