E46 M3 cluster swap

[nando]

hoveringuy (steve) is helping me a lot with the electronics. I've got a inverting circuit to control the turns/highs/fogs indicators from the stock E30 signals. Working on an op-amp circuit to convert the E30's gas gauge signal to one that will work with the E46 cluster.

the DSC error light will become my check panel indicator, and I've got plans to use one of the other idicators for when the ix's ABS goes into ice mode.

[Jean]

Dude, nice! I've been looking into one of the cheaper 'stack' looking dashes, but even the cheapest is about 600-700!

Make a guide on this with a bom! :)

[nando]

yeah I can tell you how to hook everything up and what parts I used. but hacking apart a stock cluster and phsyically making it look good will be up to you. :)

also, as mentioned before - you still need to piggyback an MSS54 for the tach/oil temp. That's a bit of a wild card, but I've seen them for $150-$200. You don't need anything fancy to run it though, no flash or anything. just remove the EML and service engine LEDs (can be hooked up to your actual ECU if you wish, of course).

Or, decode BMW's CAN messages from the DME to the cluster and build a CAN controller/signal convertor.. but a $150 MSS54 is probably easier/cheaper!

another thing helping my costs is I got the parts cluster for free. it worked, so I can sell off parts of it too.

[delatlanta1281]

I like those glowshift gauges. I run them in my e30 as well.

[nando]

going to re-use this to condition the VSS input for the E46 electronics:


I'm going to change the 78 ohm calibration resistor to a rheostat for fine tuning of the speedo output (whatever I can't change with K-factor recoding).

I've gotta relocate this bad boy, it's too tall for the board to fit inside the E30 housing with the VDO motherboard in place:


hoveringuy and others have helped me design an op-amp that will convert the voltage output of the E30 fuel level sensors to what the E46 cluster needs. My 13 button OBC will remain 100% functional. :)

[AndrewBird]

If there is enough room on the board, just get a new one and lay it down, bending the leads in a 90.

[nando]

that's basically what I'm going to do. I'll glue/tie it off somewhere out of the way. it's about 1/4" too tall right now. the only other thing that may interfere is the piezo which is easy to move and far less critical.

[nando]

LC-1 wideband gauge controller mounted on speedo PCB:


going to replace that old, crappy 16v 47u capacitor with a modern 50v equivalent. that TI chip was used on a wide range of euro cars, and the shitty capacitors were specifically named as needing an upgrade/replacement. 16v is pretty marginal for a car with a rather noisy electrical system.

after digging around in a sufficient quantity of E30 electronics - I'd say about 75% of the components are probably at EOL. Capacitors in particular don't hold up well with age, especially given the relatively poor quality that was produced in the 1980s. The PCBs used back then were total crap as well. The resistors are 10-20% margin of error, standard now is 5% (the circuits were designed with that in mind, but still). I wonder if there's any market for refurbing '80s euro electronics? probably not..

[nando]

update: a few people helped me come up with this:




the transistors on the left are setup for NPN, they will take the E30 signal indicators and convert them to a ground signal to activate the signal LEDs on the E46 cluster.

the dimmer circuit will invert the negative lead of the E30 cluster's backlighting (C2 #24) and power the LED backlights. I was just going to make them turn straight on with the switch (I never dim the backlights now), but I thought it would be more complete if I did it the right way, plus it was pretty easy.

the gas gauge circuit was the toughest. it takes the E30's signal, which is 5v empty and 0.5v full, inverts it, and offsets it to match a 0.9-2.75 signal for the E46. I also had to remove a couple resistors on the E46 cluster's board for it to have full range, but it works great. Just needs to be calibrated. :)

the bottom part of the board was just extra space, so I'm going to use it as a breakout board between the E30 and E46 motherboards.

[James Crivellone]

This is turning out very well Chris.. Nice work.

I'm actually really looking forward more to the MSS54 side of things. Its quite the concept to utilize another ECU just to run a few gauges ;)

[nando]

that side is relatively easy. hook up a couple power wires, grounds, all the temp sensors (3 coolant, one oil, one IAT), an RPM output from my MS3, and the CAN wires to the cluster. That's about it. It will throw a hell of a lot of codes, but for now I'll just remove the resistors for the check and ses lights.

I'm thinking I might also use it to control my electric fan too, but I haven't gone that far. I really just wanted to get the cluster electronics worked out, I'm going to be really busy for the next 11 weeks and I don't want to forget everything I've learned. :p

[James Crivellone]

Hah, so it will still operate without EWS?.. that is pretty funny.. although I suppose if the engine is spinning and the DME has power it will populate the bus.

Yeah..hilarious

[nando]

yeah. actually, EWS is pretty "dumb". MSS54 doesn't know if it's on or not. It still runs internally as if everything was normal - the only thing that EWS disables is the final output stage for the injectors, fuel pump, and coils.

[nando]

I thought some of the electronics guys (george) might find this funny:


my high quality, totally awesome prototype gas gauge circuit. ;)

yeah, it's ugly. I built it literally in about 5 minutes. It works well though. the real circuit will have pots instead of resistors, finding resistors in the exact ranges I need is pretty much impossible.

[nando]

well these turned out pretty dang nice:







I only need one, but it was actually cheapest to get 3 of the standard sized boards, and I don't mind having a couple spares.

I leave for California on Sunday, will be there for work for a couple days, so populating the board will have to wait until next week. I also took that teaching position which starts April 5th. Basically I want to finish this portion by then and shelve it until the quarter is over.