DIY: In depth M52/S52 OBD2 swap

[E30Reed]

What is the reasoning behind cutting the oil pickup tube from the e36 setup versus just unbolting it? I started the swap last night that I'm doing for a buddy so any tips is very much appreciated!

[328ijunkie]

Its too tight against the firewall to unscrew sometimes is my gripe. It is alot easier to put it there and not have to deal with the extra bracket.

[craiggroves91]

Also thought ide throw this in there cause it came up in another thread. Factory Diag port bracket:




PN#: 41-14-8-193-254
I stock them or you can get from any of the other OE parts vendors here/elsewhere.

I think mounting on the M3 cover is cleaner. Thats just me though

[328ijunkie]

Also thought ide throw this in there cause it came up in another thread. Factory Diag port bracket:




PN#: 41-14-8-193-254
I stock them or you can get from any of the other OE parts vendors here/elsewhere.

[328ijunkie]

^correct.

[mtlbloodshot]

Okay so the square plug that goes towards the rear of the car in the transmission tunnel is not used. Just strictly use the under shift boot wiring

[328ijunkie]

^Wait what? nono. The E30 reverse lights come through the shift boot to the trans and to the body harness. The E36 reverse light harness is in the engine harness and goes nowhere from there depending on how your wiring was done.

[mtlbloodshot]

I have to solder the two wires coming from under the shift boot to the two wires coming from the engine harness and have all four basically staying with the plug for the transmission sensor?

[Mr.SWISS]

Concerning the reverse lights, the wire that goes back towards the transmission tunnel with the O2 sensor wire is not needed?

Those green and blue wires w/ wht stripe?

That's the one's!

[mtlbloodshot]

Concerning the reverse lights, the wire that goes back towards the transmission tunnel with the O2 sensor wire is not needed?

[328ijunkie]

What works well is the reverse light harness (that you dont need). :P

[Boise]

Sweet, thanks guys.

[Jezza]

Yes forgot about that!

[328ijunkie]

^ This but you only need brn purple.

[Jezza]

How did you wire up the brown top e30 coolant temp sensor? My understanding (and I could be wrong) is that the OBD2 harnesses use one temp sensor that has both readings for the cluster and DME, hence the 4 wires going to the OBD2 temp sensor. Did you splice off one of those wires to the e30 brown top sensor?

Brown/Violet and Brown/Yellow will be spliced into the brown top connector. Leave the other two in the original sensor.