OBD1 To OBDII Management

[maharaj1]

Good Evening All,

Making progress on my 3.2 build to go back into the E36. Now that I have more or less decided on the hardware that I will be running I have started to look into the software/management and have decided that I want to run OBDII instead of OBD1. My E36 came from the factory as an automatic OBD1 vehicle. I already have the harness and all the sensors from the donor OBDII car, most of them will be replaced anyway. I remember reading a thread on what connectors need to be modified in order to run the vehicle OBDII instead of OBDI and was wondering if anyone knew the thread I was referencing, I tried searching but was unsuccessful. Any advice or help is appreciated, thanks.

[crazyyardie]

Yes in for that info too planning on doing the same on my 1995 m3 obd1. I know about wire loom sensors and it can be ews deleted but not sure which connectors need to be modified


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[bluptgm3]

You need an OBDII engine harness, and the fuel supply lines and fuel rail are different.
Are you planning to incorporate Traction Control Throttle Body as the ECU will be ‘looking’ for it.

I think it is easier to convert the S52 to OBDI.


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[ba114]

Are you planning to incorporate Traction Control Throttle Body as the ECU will be ‘looking’ for it.

Not all obd2 engines had it.

You need:
- Trigger wheel/harmonic balancer (optional if running rear/block mounted crank sensor - this varies by region i.e. EURO OBD2 cars have timing cover mounted CPS)
- Crank Position Sensor
- Cam Angle Sensor
- IAT
- ECU
- Engine Harness
- Knock sensors
- O2 sensors. OBD2 uses 0-5v sensors, very different to others.
- MAF

It can all be done fairly cheaply and is a massive benefit as far as finding faults and flash tuning.

[bluptgm3]

I don‘t believe the M50/S50 US engines have the aft crank trigger or the machined provision in the block.

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[maharaj1]

You need an OBDII engine harness, and the fuel supply lines and fuel rail are different.
Are you planning to incorporate Traction Control Throttle Body as the ECU will be ‘looking’ for it.

I think it is easier to convert the S52 to OBDI.


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I have an OBD2 Harness already, I have an entire OBD2 car for parts. Not planning on incorporating traction control.

Not all obd2 engines had it.

You need:
- Trigger wheel/harmonic balancer (optional if running rear/block mounted crank sensor - this varies by region i.e. EURO OBD2 cars have timing cover mounted CPS)
- Crank Position Sensor
- Cam Angle Sensor
- IAT
- ECU
- Engine Harness
- Knock sensors
- O2 sensors. OBD2 uses 0-5v sensors, very different to others.
- MAF

It can all be done fairly cheaply and is a massive benefit as far as finding faults and flash tuning.

I've got all the OBD2 sensors already, I bought a complete E36 M3 for the engine and parts. I'm looking for what needs to be modified on the x20 and x69 harness on the chassis side of the vehicle so that the engine harness will plug in to the correct pins. It is my understanding that the connectors on the OBD1 vehicles were pinned differently than on the OBD2 vehicles and that if I were to connect an OBD2 engine harness into an OBD1 pinned x20 and x69 harness that I would do some electrical damage. That is precisely why I want to run OBD2 instead of OBD1. Better diagnostics, tuning, etc.

I don‘t believe the M50/S50 US engines have the aft crank trigger or the machined provision in the block.

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They do no have that provision in the block. The crank sensor from the Euro spec engines mounts up front and is a hall type sensor so it works the same way that the sensor works in the rear of the block. It is a workaround for running the OBD1 engines on OBD2 management.