Author Topic: BMW M50 Crank No start  (Read 5796 times)

Offline e30sforlife

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BMW M50 Crank No start
« on: March 18, 2018, 08:02:56 pm »
Hi,
Just installed my VEMS V3 plug and play ecu onto my M52 thats been converted to OBD1. (Technically just an M50 other than fuel, ignition tables etc.)
Not sure why, but I have a crank no start.

I pulled out all 6 coil packs and spark plugs and it looks like i'm getting no spark while cranking.
I tried igniting each plug in testing mode (with dual output mode off) to see if the hardware is working correctly. I noticed that cylinders #2 and #5 in testing mode wont ignite, but all other cylinders seem to be working.

I assume i'm getting fuel because the spark plugs were wet after a few seconds of cranking.

If i plug my stock ECU in, the car fires right up. Could there be something wrong in my config? Or maybe inside the ECU itself?
I used this ECU on my old M50tu last year and everything worked fine.

Any help is appreciated. Need to fix this ASAP
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Offline e30sforlife

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Re: BMW M50 Crank No start
« Reply #1 on: March 19, 2018, 09:26:52 am »
Another thing I should add that I just realized.

When I had this ECU working on my old motor, I was running on Firmware version 1.2.10 and everything worked fine. When I installed the ECU on my new motor yesterday, I uploaded a config ment for the Firmware Version 1.2.38. The main relay in my car was flickering on and off constantly the entire config upload. Once it was done, I tried starting the car and it didnt want to turn over.

I then upgraded to the most recent 1.2.38 firmware and reuploaded the new 1.2.38 config to my ECU and I still am having issues. Is it possible that I messed up something in the software/hardware of the ECU when doing this?

Have I bricked my ECU?
Is there any way for me to start from scratch and rewrite the entire ECU to try and remove this glicth?

Any help is appreciated. Im also very new to VEMS and would love to hear from more experienced users. Thanks
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Offline e30sforlife

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Re: BMW M50 Crank No start
« Reply #2 on: March 21, 2018, 06:07:03 am »
Got the car to run! Not sure exactly what I did. I tried taking apart to ECU to see if anything was fried. Nothing smelled burnt and everything looked ok, so I put it all back together and tightened all the screws. (4 of the screws on the outside of the casing that seemed to hold electrical components together, were loose. Made sure those were nice and snug) I uninstalled and reinstalled VEMS Tune, downgraded to older, stable firmware, loaded up a config and it started right up!

I'm gonna play around with it some more and get it all dialed in, but im stoaked its up and running again!
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Offline mattias

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Re: BMW M50 Crank No start
« Reply #3 on: March 28, 2018, 07:41:40 am »
I'm pretty sure if you upgrade to 1.2.38 now that you got it working - you will have a few items to correct in the config.

With 1.2.38  the fuel pump and cooling fan "PWM" control is enabled by default after upgrading, per Hungarian standard. You have the "verify config" check button that can reveal config mistakes.

If you provide an error report next time (VemsTune -> Help -> Error report -> post link/url) then people can probably help you check these things. Takes away the guesswork from your description of the problem. I'm not sure how the outputs are wired in the PnP harness either but posting a link to that would help too, in order to verify the config corresponds to it.
« Last Edit: March 28, 2018, 07:48:16 am by mattias »