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Thread: M12/M400 ECU Solutions

  1. #1

    Default M12/M400 ECU Solutions

    Splitting from the Alternative ECU thread going on. Hope people now and in the future get something out of this.

    Like others, I was discouraged with the support of our MBE ECU. Having read the forum history, it seems it took years before those with the software were willing to release it--which is ridiculous. Once software was out, tuning cables were expensive, rare, and hard to come by; tuners who knew the Noble were far and few, and expensive. Rumors circulated about units being password protected, and it would seem some in the UK actually are. Meanwhile, MBE deviated from the standard rs232 pin-outs to discourage owners from not buying their cable directly--despite the ECU no longer being sold, and M12/400s no longer being made. Our ECU is a pretty capable unit, certainly better than what most sports cars get from the factory. But its been difficult for owners to realize the potential without spending an arm and a leg on a cable and tuning, or a new ECU. But Im pretty sure none of those things are issues any more.

    For anyone following or interested, here are the background posts I made up to this point.
    Post 1:
    I have a laptop and a standard usb to RS-232 cable that Ive used in the past to write my own datalogger and analytics software. Today, I performed a relatively scary but successful test. Scary because a lot of people say a "special" tuning cable is required to flash our ECUs, and I was a bit worried about blowing my ECU and what that would do to my winter project budget.

    Using the Easimap software, I connected my laptop to the ECU. I then downloaded the chip file from my ECU. There is a notes section where I compiled a new note for this test. And uploaded a new chipfile into my ECU. After verifying that I could now pull that data back down from the ECU, I started my car again. While I havent driven it or inspected that the maps are all intact, the car does seem to run and idle just fine.

    So, I was able to upload data into the ECU successfully, no password required. Because the entire data is uploaded into a single file, and because its all just bits on the same EPROM, I dont see any reason why the ECU maps and variables would be any difference. It may be risky, but I plan to eventually muster the courage to proceed with further tests. If standard cables do actually work just fine, and no password is really needed, this could be a game changer for many of us I think.
    *disclaimer: Im NOT saying its safe to upload data with a standard cable. I dont know yet, more tests need to be done. My one single upload is just a single data point...So dont go trying this unless youre willing to accept whatever happens.
    Post 2:
    Its been a lot of years since Ive wired up an RS232 cable for anything, so I went back and took a look at the pinout and compared it to the wiring diagram supplied for the circuit that is apparently necessary to make an MBE "tuning cable". Heres the scoop:

    The proper tuning cable uses a simplified 3-pin wiring scheme. This was a common basic wiring mechanism for situations where a more complicated handshake was not necessary. It utilizes a ground, a transmit, and a receive. A more complicated scheme used additional pins to request and clear to send and receive signals. So the tuning cable dispenses with these extra signals and uses simply the ground and tx/rx pins. To this, it add 2 resistors that attach to pins 4-7 of the connector, which guess what! Happen to be the tx/rx handshaking signals used in the more complicated pinout. *IF* the easimap 5 software turns off flow control, then these pins wont be used either way, regardless of what kind of cable you have hooked up. If not, you can disable flow control in the COM settings in Windows, so thats no problem. I have my flow control disabled when Im hooked up to the ECU.
    Only item left...I wish I knew how those resistors were meant to interact with the ECU itself...Its just looping back a signal from the ECU to ground, but I wonder if the ECU even cares about that stuff at all.
    Last edited by jpwden; 12-28-2016 at 06:55 PM.

  2. #2


    Turns out the ECU may care if its a standard cable instead of the MBE tuning cable: While I have used a standard serial cable with Flow Control turned off to upload a simple piece of device data to the ECU, based on the differences in the pin connections it *could* be potentially dangerous for the ECU. Im happy to provide a technical analysis for any interested in knowing, and its not incredibly complicated, its just more than I want to type. So, I took the time to develop a tuning cable. Ive been using it all day today, testing that changes in the chipfile are being written successfully to the ECU and manifesting in the performance of the car.

    So there are 3 salient conclusions in favor of our stock unit:
    1. Our ECUs here in the US are *NOT* locked or password protected, unless a previous owner has purposely input their own 4-digit pin for security. If your ECU is locked, I can show you how to unlock it. With the proper software (which is now freely available) and tuning cable, there is no restriction on tuning our own cars.
    2. The ECU and software are relatively easy to work with. While tuning is a tedious process that takes patience and care, our software can be learned quickly and safe changes can be done in a relatively short period of time.
    3. Tuning Cables no longer need to cost a crazy $400. Since I already spent the time to research all this, fab the cable, use it to modify my maps, Im going to fab up a few extra to keep on hand. If anyone is interested in buying one, shoot me a PM. These can be used on laptops that do not have an rs232 part. USB is fine.

    With that said, there are also some good reasons to switch to another unit: Availability of parts/support if the ECU has a problem, lack of functionality available on other aftermarket units, age...the fact that it still uses an rs232 port lol, etc etc...

    Im still in consideration of some day switching to another unit--Ive looked at the Holley EFI with Calvin. However, I think that for those of us that arent racing at a very high level, our factory unit is a good one and I dont believe at this point there is any reason to be discouraged with the factory MBE ECU. If anyone has an questions/concerns with your ECU or is having an issue, feel free to post here or PM/email me and Ill help with what I can...
    Last edited by jpwden; 12-28-2016 at 07:30 PM.

  3. #3


    Great work Josh and thanks for all the hard work.

    I'll definitely take a cable when you have some made up. I need to send back the cable I have soon. Do you want to compare yours to this one at all to verify anything?


  4. #4


    Thanks Ken! Ill let you know when theyre ready.

    No need to verify anything with the cable you have in hand, I have everything spec'd out as it should...Feel free to send it back.

  5. #5
    Join Date
    Jan 2016
    Littleton, CO
    Rep Power


    Great work, Josh. As all of us EE's know, as long as the smoke stays in everything is OK After all, it is the smoke that allows the electrons to solve the differential equations so rapidly Seriously, though, as long as these things are taken step by step and backed up with good engineering and research, the risks should be able to be mitigated; maybe not totally eliminated, but certainly mitigated and made relatively low. It will be good for you Noble guys to be able to solve some of these riddles and enable more of a DIY flavor to the car.

  6. #6


    Thanks Calvin.
    Next time we get together, Ill have to show you some of the stuff Ive been working on with the chipfile maps...

  7. #7
    Join Date
    Dec 2009
    SugarCreek (Dayton), OH
    Rep Power


    I always thought it was magic smoke because i have tried to put regular smoke back in and it never seams to work

  8. #8


    Hey Ken, the cable is ready to go.

    I will have 10 cables total (including Kens) if anyone else wants one...

  9. Default

    Count me in. Let me know when/where/how much.
    Maybe a quick tutorial also?

    You are using Easimap 5?

    My starting goal is to lean out the hot idle some. as per my AF gauge, at a steady idle, the AF is low 12/upper 11s. seems too low to me. But this is where the tutorial comes in.

  10. #10


    Sure thing, Doug. There going to be $100 even, 1/4 the cost of the other ones out there. For anyone out of state that wants one, Im guessing tack $5 for shipping on to that.

    I will be happy to give a quick tutorial, and use the cable on my car or yours so you know it works as it should.
    You need to be using Easimap 5. Ive played around with more recent versions of Easimap and the ECU doesnt like them, so once installed, stay away from the upgrade button...
    Additionally, for whatever laptop you have, if you do NOT have a db9 rs232 port, go out and get yourself a GOOD quality USB to rs232 cable. Again, Im happy to help you set it up via usb or rs232 and demonstrate that its talking to the ECU properly.

    When the snow is gone, maybe next weekend, youre free (both Doug and ken) to swing by the house and we can get it all figured out...

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