E46 M3 cluster swap

[RobertK]

I know this kind of work doesn't come cheap but for a clean install I would be willing to pay up.

I may be able to grab some S62 clusters this weekend when I pick up my engines, anything else I should try to grab with them?

[nando]

Pigtail harnesses for the cluster, external temp sensor, maybe the LCM.

I would grab ews modules, keys and transponders if you can, the dme is worth more with an ews module.

[nando]

I cracked the "code" :D

after an hour of changing each byte in the fuel gauge one at a time, I found the pattern.

turns out, they aren't all paired as FF,FF. The fuel curve (in liters) is just FF. the ADC curve (x100) is FF,FF. All this time I thought they were all paired as FF,FF; no wonder I couldn't figure it out. :(

the first 5 FF's are the fuel curve in liters for ADC2. 00, 08, 11, 19, and 21 in hex translate to 0, 8, 17, 25, & 33 liters. the next sequence is the ADC curve for ADC2, 5 pairs of FF,FF 's. ADC1 follows the same pattern starting with 00, 07, 0d, 14, & 18 which equals 0 7, 13, 20 & 24 liters.

with that figured out adjusting the curve is easy! I came up with two that work perfectly.

This one works linearly but most of the resolution is on the "full" end. 0F is 15 liters or 1/2, which is the second value in each curve:
00,0F,17,1C,1E,00,48,00,99,00,EA,01,3C,01,86,00,0F ,17,1C,1E,00,48,00,99,00,EA,01,3C,01,86

I wanted more control over both ends of the curve, so I shifted the 1/2 mark (0F = 15liters) to the center of each group of 5 bytes:
00,08,0F,17,1E,00,48,00,70,00,99,00,EA,01,86,00,08 ,0F,17,1E,00,48,00,70,00,99,00,EA,01,86

08 is the 1/4 mark. each ADC will read 8 liters at 1/4, 8+8 = 16 or about 1/4 of 60l. 00,70 is the corresponding ADC value for the 1/4 mark (11200).

The E, 1/4, 1/2, 3/4 and F marks on the E46 gauge match up with the E30's gauge *perfectly*. :D

I still have one issue to resolve - running the E46 cluster for long periods of time with nothing hooked to the gas gauge input results in the gauge becomming non-responsive. tthe fuel level changes internally as does the ADC, but the gauge's fuel level doesn't react accordingly, unless you reset the cluster or shut it off and turn it back on. I've had it do this a couple times before and was able to get it back, but right now I don't really remember how I did that. it was some combination of shutting it on/off, software resets, and disconnecting the gauge input until the needle responded..

fun times. :)

[Wh33lhop]

Niice! I'm not sure I would want the gauge to match my e30 gauge though. I'd probably prefer it to be accurate. :p

[Vedubin01]

Super impressive Chris, Nice work!

[nando]

Niice! I'm not sure I would want the gauge to match my e30 gauge though. I'd probably prefer it to be accurate. :p

LOL, well, its a bench setup gauge. Actually, it seems to be very accurate. The gauge face on the e30 just doesnt make sense.

[nando]

fuel gauge is still stuck. pissing me off.. but making some other progress:

[FredK]

I wish I had a 9K tach. I have no idea what's going on beyond 7. Haha.

[nando]

Well i have 2 more adapter boards :p

[AndrewBird]

What's with the blue tape?

[nando]

To mark the original needle position

[Farbin Kaiber]

Every time I see this thread, I'm slackjawed.

[golde30]

fuel gauge is still stuck. pissing me off.. but making some other progress:

Nice. Turn this into a DIY kit. Would be awesome.

I dont have a problem with trimming/fitting to the e30 dash, but the wiring and circuit boards are beyond me.

[RobertK]

Pigtail harnesses for the cluster, external temp sensor, maybe the LCM.

I would grab ews modules, keys and transponders if you can, the dme is worth more with an ews module.

Nabbed 4 ECUs with the EWS, 2 with keys. Unfortunately, no LCMs, temp sensors, or wire harnesses were left because they had crush all the cars. :(

[nando]

nice :D

if you don't want EWS, you could sell them for good money and get one on ebay without EWS (cheap since they are useless in a stock car without a matching module). Not having a matching key is less of an issue, you can even code your own keys with a little investment (I haven't gone that far, my MSS54HP came with a matching key, EWS module, and transponder).

did you get a cluster or say you had one? you don't really *need* the LCM, but it could be nice to have. I considered convering my entire car to use the LCM but decided it wasn't worth it. I am trying to keep my mods to the cluster reversable in case I decide to do that later.

I don't know how similar the shape of the M5 cluster is to the M3. I am pretty sure that you can use the M5 and M3 clusters interchangeably. MSS52 = MSS54 with 2 more injector and coil drivers. the M3 cluster can be changed from a 6cyl to an 8cyl coding with 1 setting.

would you be willing to send me an M5 cluster/DME to test? I could test MSS52 with the M3 cluster, or MSS54 with the M5 cluster. My gut feeling is the M3 cluster is far more common, thus cheaper, than the M5 cluster, and they're functionally the same thing. I also have a feeling the M3 cluster may fit better inside the E30 housing.