Originally posted by nucci
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How did you test it?
I didn't know this - are there places to read about it?
I figure the people likely to do this swap DIY style are probably E30 or E36 owners, and so I'm trying to figure out whether there are more benefits to keeping the E46 M3 cluster and integrating the gauge movements/circuit board into an earlier dash housing, or figuring out how to run without the E46 M3 cluster and still keep the DME and EWS satisfied.
If the E46 M3 cluster is kept, I would imagine that most swappers would like their odometer to retain the chassis' original mileage, and most E46's getting parted out have from 40K to 100K. Many E30 and E36 chassis have 3-5x that many miles. In order to "add" miles to one of these clusters with hobbyist-level programmers, you need to disassemble the cluster, de-solder the M35080 chip, read the raw dump and save it, create a new file for the M35080 which retains the VIN but has your new desired mileage and a corrected checksum, resolder the chip and reassemble the cluster, erase some/all of the code on the chip in the EWS box (still not clear on this) and reset its mileage to 316km, and then you can plug all these parts into the car and go. If done correctly the EWS will then update its mileage from the cluster when everything is powered up. If you are keeping the LCM you will need to change the mileage there too, but you can do that with inexpensive diagnostic tools.
I can't see any benefit to keeping the E46 LCM though, it will cause way more headaches, especially if VIN's don't match. You have to do some mods to the cluster for the indicator lights to work but it's not that big of a deal, and it frees you up to use the extra spaces for more useful purposes. like a wideband and oil pressure gauge. :D
If this can be done without that cluster and all its drama, it might be a better option for some. However, I don't think you will have cruise control unless somebody can interpret the CAN signals created by the MFL steering wheel buttons. The buttons on the right side of the steering wheel supply commands on the K-Bus to the cluster, which turns them into CAN commands and sends them to the DME.
although, there is an issue with recoding the K-factor without changing the odometer's checksum. basically, you're stuck with the K-factor's built in to the cluster for the odometer, even though you can code new ones, it will throw a checksum error because I believe the E46 cluster stores pulses, not kms or miles. You can change the speedometer to whatever you wish, which is nice. fortunately, the built in odometer K-factors are extremely close to what I'd need, close enough that messing with the odometer reading and checksum isn't worth it. And there are two to choose from which at least gives a little bit of wiggle room.
what I really want to find out is, what does the DME actually do without the DSC/ABS system & emissions junk? if it's just going to throw an error light - who gives a shit? at the price people are charging for flashes, it hardly seems worth the trouble. I'll find out eventually but I need to finish other things first. :)
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