Obd2 harness and engine in obd1 car

**bimmerbumm193** · 03-13-2016, 07:25 PM

Searching for this topic mainly brings up obd2 to obd1 conversions, but i am asking what is involved jn running a complete s52 obd2 engine, harness and ms41 ecu in a pre 95 car. I am looking for shells to build a turbo hillclimb car and wanted to know how big a deal it was to do the swap in case i find a nice obd1 car? Is it just a matter of plugging the engine harness into the round x20? plugs and redo the fpr regulator? Or do you have to redo the whole underdash wiring to install the obd2 port? Or is it so much a pain in the ass that i should only look for obd2 cars? Thanks!

**Butters Stoch** · 03-13-2016, 07:27 PM

Maybe find a 328. Maybe cheapest way out. Then drop in LSD and engine.

**flyfishvt** · 03-13-2016, 08:27 PM

You will have to get ews removed from the DME. OBD2 port is super easy but you don't need it as long as you have a working 20 pin port. That being said the 16 pin obd2 port simply taps off the 2 k lines in the 20 pin port. Add 2 grounds and a switched power line and you're done. Any e36?wire diagram will show you which pins get which wires. FPR should not be a problem to modify to the obd2 but lots of FI guys bypass it and use an after market regulator.

I can't tell you about connecting the engine harness to the chassis but I'm sure people that gave done s52/e30 swaps or s52/ti swaps can.

**flyfishvt** · 03-13-2016, 08:36 PM

Or you could look for a nice 328

**busterhax** · 03-13-2016, 09:48 PM

Plenty of people do it. It's nothing special.

**bimmerbumm193** · 03-13-2016, 11:09 PM

Originally Posted by flyfishvt

You will have to get ews removed from the DME. OBD2 port is super easy but you don't need it as long as you have a working 20 pin port. That being said the 16 pin obd2 port simply taps off the 2 k lines in the 20 pin port. Add 2 grounds and a switched power line and you're done. Any e36?wire diagram will show you which pins get which wires. FPR should not be a problem to modify to the obd2 but lots of FI guys bypass it and use an after market regulator. I can't tell you about connecting the engine harness to the chassis but I'm sure people that gave done s52/e30 swaps or s52/ti swaps can.

What is the 20 pin port you are referring to, is that a port in the cabin?

Buying a 328 is a good option, but once u add up buying m3 trailing arms, axles, front spindles, etc im almost at buying a cheap m3...well almost, guess it depends on condition.

Other than the zf trans, what does a 323is lack?

**vollosso** · 03-13-2016, 11:31 PM

Its very easy.

If you pm me your email ill send you what i know.

**Pythonz** · 03-13-2016, 11:53 PM

I could use some help as well, I have the same set up.

**Butters Stoch** · 03-14-2016, 05:14 AM

Originally Posted by bimmerbumm193

What is the 20 pin port you are referring to, is that a port in the cabin?

Buying a 328 is a good option, but once u add up buying m3 trailing arms, axles, front spindles, etc im almost at buying a cheap m3...well almost, guess it depends on condition.

Other than the zf trans, what does a 323is lack?

328 axles break due to traction, pretty easy on the dragstrip , sometimes on the street. Hill climb is different isn't it ?

**flyfishvt** · 03-14-2016, 06:06 AM

The e36s have a round 20 pin diagnostic port in the engine bay. On 6 cylinder cars it's up near the DME cavity. On 4 cylinder cars it's on the other side of the engine bay. It's used to access all the different modules in the car to perform diagnostics and coding functions. Starting in 96 all US spec cars have a 16 pin obd2 port under the dash. BMW equipped US spec cars with both ports until 2000 or 2001. In cars with both ports the obd2 port can only access the DME and the 20 pin can access all modules like DME, srs, abs, instrument cluster, ews, heat/ac controls etc etc

**niemanj** · 01-23-2020, 04:48 PM

Hi,

The ‘it’s very easy’ caught my attention. I recently acquired a fully setup spec E36 (‘94 325) but unfortunately the engine blew rather quickly on that one. So I managed to acquire an M52 engine from a ‘97 328. I have put the engine and the ZF trans in the car and start to work on the electrical part. The chassis only has an x69 and an X20. The harness had and X20, X69 and an X6031. I’ve read that I need to rewire some stuff in these connectors but cannot find what. Full disclosure I have a tuned DME in which the ASC, SAP, redline, speed limiter, etc. all have been removed.

In some case I’m reading that the OBD2 X69 is just ABS/ASC and I can delete this completely and ABS will still work. The X69 in the OBD1 chassis has a bunch of pins in there but I have not been able to find anything on the internet that tells me what these are for. Similarly teh X6031 on the OBD2 harness seems to have some important pins in there. Not sure I need these to run the car but if I want the data link connector to work it seems I need to at least connect pin 8 to power.

On the X20 a lot of the pins are similar (internet has quite a bit of info on this connector). Pins 8,9,10,14, 16 and 17 might be different between the chassis and the harness.

Anyway as you can see I’’m quite confused and maybe in it over my head but I’m determined to get this running. Any pointers would be helpful. I have the Bentley and the Electric Troubleshooting manuals for both chassis and engine but have trouble finding useful information in those.

Thanks in advance for your help, Jan

Originally Posted by vollosso

Its very easy.

If you pm me your email ill send you what i know.