RomRaider

Hello everyone, I converted my M50B25TU to MS41 and I'm having problems with the tune, tried many things with knock maps since it's iron block, nothing... The car sputters a bit at blip on the throttle while idling, it drives somewhat nice, when I decel sometimes the RPMs drop so low that the oil light pops on and then continues to idle, at WOT the car starts having problems after 4500-5000 rpm when it sounds like it kinda missfires and then it turns off a few cylinders for a short time then starts working normally. Sadly I cannot get my logger to work since there seems to be an issue with the cable, the new one takes some time to arrive since I don't want to buy something cheap again that is offered to me at the moment. Don't want a finished tune from someone, just some advice and where to start with the tune and to point me in the right direction. I would pay a tuner, but there are none here it my country. Thank you everyone in advance.

I dont get it. After all your previous posts you were mentioning the car runs fine and you were logging the data. Now this? I highly doubt that anyone can remotely troubleshoot ur issues. You need to log and check dtcs and whatever. Maybe not even ecu tune related hardware issues...

Trust me dude… I’m confused as you are after reading this, the logger starts tripping out as sokn as I start the car, I ordered a new cable in hopes that it would fix my problem since the X20 to OBD2 adaptor does seem iffy and cheap, I tried turning the knock sensors off just to test how the car will behave and it ran better than usual, only DTC I’m getting is for bank 2 O2 sensor and I’m waiting for a replacement to arrive, the stores here are very bad with their brand offers so I had to order a bunch online and have to wait every time I order… I’d love to get my car working so I can contribute to RomRaider and make long post with how to for people who are looking to convert their M50s to MS41 (hardware and software wise)

Hello,

what did you converted to MS41 ?

engine harness ? M50 M52 ?

did you replace sensors crankshaft camshaft ?

whats about the idlevalve ?

m50 throttlebodys diameter are different like M52s

did you use USB cable ?

Edit:

readed your previous post

you can use M52 crankshaft (halleffect sensor) and M50 (inductiv sensor) camshaft sensors both VDO/Siemens

Replaced everything needed for MS41 conversion, car starts and runs, drives somewhat nice, not perfect but it can run in normal daily driving, my problem is at WOT, and when it idles when I blip the throttle it kinda sputters at start but revs up nice. And since the logger is causing me problems I have to tune it to work somewhat normal so I can pass MOT and register it in month and a half... *facepalm* the timing for these problems couldn't be worse...

how r you trying to log and with what type of cable and connector? did u extend the cable so u can log inside the car? meaning the usb converter must be inside, otherwise interference from the coils will shut it down once u start the car.

also from ur very short log u posted before. ur stfts are all whacky. u do know that ms41 requires other o2 sensors than bosch motronic. right and have different connectors? how did u convert the o2s ?

Should I extend the X20 to OBD2 connector adapter cable so that the connection is inside the car ? I haven't done that it is very short from the box, and for the OBD2 to USB port in laptop I use K+DCan cable, got INPA with the cable when I bought it, everytime I went out to log I had a friend sit next to me and hold the laptop, and as far as O2s go, I bought new M52 O2s (NTK brand) Did the whole conversion like it was factory MS41 electronics, only thing that stayed Bosch is the TPS.

un need something like this

Low Profile Right/Left Angle OBD 2 II Extension with Flat Ribbon Cable 3'/1m

google it.. u need to connect it to the 20 pin, so that the actual USB obd2 dongle is inside the car

Thanks, I’ll order it and see if anything changes, hope I will be able to make some logs soon and complete this conversion once and for all and then make a complete guide on how I did it for people in the future.

small tip:
keep all info in one thread, now people need to jump to a different thread to know the history of your previous problems.

had the same problem with USB cable idle logger reads , higher rpm logger disconnected.

tried USB cable and selfmade glovebox OBD connector same.

since i use RS232 cable and selfmade glovebox OBD connector runs perfect.

build the OBD straight into my adapter MS40.1 - MS41 harness.

So my OBD2 extension cable arrived, I’ll try to plug it in and see if anything changes if not, should I just cut of the end that I don’t need and wire it to be in to be an OBD2 plug in my glovebox like Cpt-ECU said, if yes, then should I just follow the wiring pinout of OBD connector and X20 connector and connect the wires of the extension to the wires that go to the X20? Don’t want to ruin the engine harness or something, thank you in advance!

alternate you can use BMW 20 pin to OBD 16pin adapter and make the wires longer and check the pinouts some cheap adapters pinout are not correct.

Female OBD 16pin---------- Male BMW 20 pin

4,5------------------------19 (Ground)
7,8------------------------17,20 (Diagnostic K-Line)
15-------------------------15 (Diagnostic L-Line)
16-------------------------14 (Power) 18 (switch write access)
1,2------------------------16 (Ignition switch +12 Volt)