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Thread: OBD1 to OBD2 swap on an OBD1 E34 M50B25TU?

  1. #1
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    OBD1 to OBD2 swap on an OBD1 E34 M50B25TU?

    Anyone done this or done any research on this?...

    Im swapping my internals out for 3.0 parts and boosting the car but also want to change to OBD2... I have searched but not found anything solid?

    Sent from The Moon

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  2. #2
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    You wouldn't swap M54 internals into an M50 only to try and convert the M50 to OBD2.

    Just swap the M54B30 in w/ cluster/etc. Though quite honestly there's a ton of stuff that needs to be in place for complete OBD2 functionality.

  3. #3
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    Thanks for your reply

    I'm not looking for full functionality but to be able to make use of the mappable newer ECU, OBD port etc, is there a better way to get the ECU on it's own onto the loom and working? I'm already looking at things like EWS delete etc... My local guy is pretty good with the MS41 and have been told that it is a better ECU to use?

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  4. #4
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    Considering TRM has told me that they can make an OBD2 ecu ready for drop into an e30 with a wiring adapter I would imagine that would be the only thing of concern, and it shouldn't be a problem if e34 and e36's share the same C101 connector. So flash the MS41 and put in a wiring harness you'll have to change the o2 sensor, maf, and cts though.

    Getting the OBD2 port to work is simply a K+L line connection from the wiring harness.

  5. #5
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    Quote Originally Posted by Nomade30 View Post
    Considering TRM has told me that they can make an OBD2 ecu ready for drop into an e30 with a wiring adapter I would imagine that would be the only thing of concern, and it shouldn't be a problem if e34 and e36's share the same C101 connector. So flash the MS41 and put in a wiring harness you'll have to change the o2 sensor, maf, and cts though.

    Getting the OBD2 port to work is simply a K+L line connection from the wiring harness.
    Brill, thanks for the info!

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  6. #6
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    Obd2 e34 with European original m50b20-25 built into forged trm "s52" +Trm turbo has been done also and proven even more refined than obd1 trm turbo e34 due to sheer brainpower.

    Just run euro 328i front crank position sensor as its direct interchange for the s52/m54 unit

    Sent from my GT-N7100 using Tapatalk 2
    Last edited by wanganstyle; 03-19-2013 at 09:31 PM.
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  7. #7
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    Ive done a few 24v swaps with M50/S50's running OBD2. Crank sensor is the only hurdle (if it is even one)
    460whp/515wtq wifes MMW tuned 335i

  8. #8
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    Quote Originally Posted by wanganstyle View Post
    Obd2 e34 with European original m50b20-25 built into forged trm "s52" +Trm turbo has been done also and proven even more refined than obd1 trm turbo e34 due to sheer brainpower.

    Just run euro 328i front crank position sensor as its direct interchange for the s52/m54 unit

    Sent from my GT-N7100 using Tapatalk 2
    This!

    Do you happen to know which Wiring loom was used? E36 328? I have access to several different looms from E36 and E39 (M52/M54) but was going to get my hands on the M52 and use the euro crank sensor...

    Quote Originally Posted by 328iJunkie View Post
    Ive done a few 24v swaps with M50/S50's running OBD2. Crank sensor is the only hurdle (if it is even one)
    Brill! Which OBD2 loom did you use? It is going into an E34 with M50B25TU

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  9. #9
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    E36 ones are nicer to work with than the E39's. Any 96+ 328/323/m3 one will do. M54 wont work. Youll have to do some rewiring in various places for everything to work 100% but its not too bad
    460whp/515wtq wifes MMW tuned 335i

  10. #10
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    Quote Originally Posted by 328iJunkie View Post
    E36 ones are nicer to work with than the E39's. Any 96+ 328/323/m3 one will do. M54 wont work. Youll have to do some rewiring in various places for everything to work 100% but its not too bad
    Excellent, thanks ... I am looking to tackle the start of the wiring this weekend... My M54 parts haven't arrived yet so will get the wiring done in the mean time...

    Is there a write up online of the various rewiring or is it self apparent when installing?

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  11. #11
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    Quote Originally Posted by Spice Boy View Post
    This!

    Do you happen to know which Wiring loom was used? E36 328? I have access to several different looms from E36 and E39 (M52/M54) but was going to get my hands on the M52 and use the euro crank sensor...



    Brill! Which OBD2 loom did you use? It is going into an E34 with M50B25TU
    I sent a s52 engine automatic e36m3 harness and its misc temp sensors, vanos sensors, 02, knock, cam sensor.

    e36 320i/323i/328i euro obd2 items used:
    front hall type crank position sensor

    Install was pretty easy as e36 chassis was designed for both obd1 and obd2; other chassis would also be ok.

    Usa obd2 has 4 o2 sensors besides z3, euro obd2 all have 2 only.

    Usa obd2 has crank position sensor in block like m54 with trigger on crankshaft

    Sent from my GT-N7100 using Tapatalk 2
    Last edited by wanganstyle; 03-20-2013 at 08:06 PM.
    Wanganstyle Powertrain
    http://www.wanganstyle.com/

    S54B32 E36 M3 DTA S100 Sedan Street car full swap:
    http://forums.bimmerforums.com/forum....php?t=1437471

  12. #12
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    Quote Originally Posted by wanganstyle View Post
    I sent a s52 engine automatic e36m3 harness and its misc temp sensors, vanos sensors, 02, knock, cam sensor.

    e36 320i/323i/328i euro obd2 items used:
    front hall type crank position sensor

    Install was pretty easy as e36 chassis was designed for both obd1 and obd2; other chassis would also be ok.

    Usa obd2 has 4 o2 sensors besides z3, euro obd2 all have 2 only.

    Usa obd2 has crank position sensor in block like m54 with trigger on crankshaft

    Sent from my GT-N7100 using Tapatalk 2
    This is very very useful... So seeing as I will be using all Euro parts I will be at an advantage already over using USA parts, correct?

    I will focus my choice on looms on the E36 only as I want to simplify the installation as much as I can. I am capable of doing more complicated wiring but why make the job any harder than it has to be, right? lol...

    "Usa obd2 has crank position sensor in block like m54 with trigger on crankshaft" I understand that I can use the Euro E36 328 crank position sensor too, is this also correct?

    Sorry to bombard you with questions, I'd rather make sure I am armed with knowledge when doing the car than attacking it blind lol... As I am doing the work myself

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  13. #13
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    Just to update, I've successfully fitted an M52B28 OBD2 into my E34 as a test run for my other engine... With MS41.0 ecu and all OBD2 sensors in place...

    So it can be done, and not too difficult either!

    Avus E34 525i Sport with Stroked M50B30TUHybrid, Lysholm AX1600 Supercharger and a nut at the wheel...

  14. #14
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    Quote Originally Posted by Spice Boy View Post
    Just to update, I've successfully fitted an M52B28 OBD2 into my E34 as a test run for my other engine... With MS41.0 ecu and all OBD2 sensors in place...

    So it can be done, and not too difficult either!
    Did you use an e36 loom!?
    How does it work with gauges and so!? I mean, does it fits aswell and everything is functional!?

    Ive been told that Siemens is much more refined and efficient than Bosch units. And you make more power out of them.
    Did you use the m50 manifold!?

    What was the major problem/ biggest deal when swaping the harness?

  15. #15
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    Quote Originally Posted by 4dri4n View Post
    Did you use an e36 loom!?
    How does it work with gauges and so!? I mean, does it fits aswell and everything is functional!?

    Ive been told that Siemens is much more refined and efficient than Bosch units. And you make more power out of them.
    Did you use the m50 manifold!?

    What was the major problem/ biggest deal when swaping the harness?
    @4dri4n Turns out I'm getting the M52B28 fitted in the e34 after all So far I have found out that you have to use e36 loom because e39 harness is different and the I'm not sure where the 2 plugs go that join together the engine harness with the main car harness. Im just not sure that the e36 engine harness pins on the 2 round connectors that connect to the main harness near the fuse box have the same pinout as e34 :/ Otherwise it would be easy as...hmm...

  16. #16
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    Quote Originally Posted by Mixzzz View Post
    @4dri4n Turns out I'm getting the M52B28 fitted in the e34 after all So far I have found out that you have to use e36 loom because e39 harness is different and the I'm not sure where the 2 plugs go that join together the engine harness with the main car harness. Im just not sure that the e36 engine harness pins on the 2 round connectors that connect to the main harness near the fuse box have the same pinout as e34 :/ Otherwise it would be easy as...hmm...
    I know a guy who made it with the e39 loom, on a e30. And it works! He told me all clusters are fully functional and so... I guess I will not know until Im there. E39 engines are more accesible and less trashed. Thtas why I prefer an e39. But I guess a 323i loom will work aswell I dont know. Maybe 320i m52b20 engines have the same loom aswell? Im sure it would be even cheaper. Then I would just have to mate the e39 DME with it and fire it up!
    The guy I know told me that he has 2 keys in order to make it work and avoid a DME flash. Which is not a problem at all but well, thats how he did it. He leaves the original m52 key always switched on and the e30 key to fire it up. I dont like that at all but it works.

    After reading a little bit, I think that definitely OBD2 is the way to go. It doesnt makes any sense to keep it OBD1. I will start as soon as summer ends and get a little bit colder here cause now I just cant do anything u.u

    If I could I think I would preffer to keep it all e39, but if its not possible then I guess I will search for an e36 loom...

    And what about the mpg needle!? Would it work aswell!?

  17. #17
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    Quote Originally Posted by 4dri4n View Post
    I know a guy who made it with the e39 loom, on a e30. And it works! He told me all clusters are fully functional and so... I guess I will not know until Im there. E39 engines are more accesible and less trashed. Thtas why I prefer an e39. But I guess a 323i loom will work aswell I dont know. Maybe 320i m52b20 engines have the same loom aswell? Im sure it would be even cheaper. Then I would just have to mate the e39 DME with it and fire it up!
    The guy I know told me that he has 2 keys in order to make it work and avoid a DME flash. Which is not a problem at all but well, thats how he did it. He leaves the original m52 key always switched on and the e30 key to fire it up. I dont like that at all but it works.

    After reading a little bit, I think that definitely OBD2 is the way to go. It doesnt makes any sense to keep it OBD1. I will start as soon as summer ends and get a little bit colder here cause now I just cant do anything u.u

    If I could I think I would preffer to keep it all e39, but if its not possible then I guess I will search for an e36 loom...

    And what about the mpg needle!? Would it work aswell!?
    The MPG needle should work as far as I understand.The loom for all M52s in e36 should be the same as in the ETM 320i,323i and 328i they are all under the same section. Digging trough electrical troubleshooting manual on both cars I have made up a chart on the X20 connector
    1bdb1a1121.png
    Green - No modifications needed
    Yellow - Not very important but might as well get it done
    Red - Need to sort it out
    Last edited by Mixzzz; 07-23-2017 at 08:38 PM.

  18. #18
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    320i wont work. It runs MS40.1. Different harness and pinouts.
    I'm running my m50b25tu on OBD2 without issue. In australia we only even got OBD2 with timing cover mounted CPS so was never an issue.

  19. #19
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    Quote Originally Posted by ba114 View Post
    320i wont work. It runs MS40.1. Different harness and pinouts.
    I'm running my m50b25tu on OBD2 without issue. In australia we only even got OBD2 with timing cover mounted CPS so was never an issue.

    Realoem says that 320i with m52b20 run on MS41. However its true that m50b20 320i run on MS40.1 wich may be different for sure...

    http://www.realoem.com/bmw/enUS/part...&q=12141429999

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