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Old 02-09-2019, 07:24 AM   #1
TeXJ
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obd1 back to obd2 how-to's?

Have an obd1 m52b28, bought it this way, that runs like crap. I've been told to really look into putting it back to obd2.


I've tried to find threads on how to do this and what is needed. I've come up with zilch.


Any help would be appreciated.



I'd assume I would need the engine harness, but would any m52b28 harness work or does it need to be year specific?


Which sensors would I need as well?
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Old 02-09-2019, 09:53 AM   #2
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You need m52 sensors and wiring harness to make it work. Well tps sensor can be current one because those are same Wiring harness can be from any car, but e36 one is easiest to put in e30.
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Old 02-09-2019, 01:19 PM   #3
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Originally Posted by pazi88 View Post
You need m52 sensors and wiring harness to make it work. Well tps sensor can be current one because those are same Wiring harness can be from any car, but e36 one is easiest to put in e30.
Thank you!
So I could use an engine harness from say a 325i e36 and that would good as well?

The reason I ask is that these are getting hard to come by. I only saw 2 BMWs and both were 5 series at the junk yard that last time I went.
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Old 02-09-2019, 02:07 PM   #4
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Quote:
Originally Posted by TeXJ View Post
Thank you!
So I could use an engine harness from say a 325i e36 and that would good as well?

The reason I ask is that these are getting hard to come by. I only saw 2 BMWs and both were 5 series at the junk yard that last time I went.
No. 325 has m50. You need e36 with m52 320/323/328. E39 wiring works too, but the wires for ecu connector are too short to reach stock ecu location in e30 and chassis connector is at the wrong side of the car. So lot more things to do than with e36 engine harness.
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Old 02-11-2019, 08:12 AM   #5
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You'll also need to modify/replace your headers to accept o2 sensors, the OBD1 harness only has 1 harness post cat.

OBD2 harness has an o2 sensor in each bank and another one downstream for emissions (not crucial for engine management).

Also need an OBD2 DME. Not sure how the OBD2 harness meshes with the body harness, but you should check into that.
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Old 02-11-2019, 08:33 AM   #6
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aww good points. I'd assume then that the DME used by the donor vehicle should also be taken.

The exhaust is good, I have the ebay long tube headers already on the car. They have O2 sensor bungs on each side. I'm catless as well so I would need to have the rear most o2 sensor deleted.
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