VR or Hall

[ahriley91]

Does an M50TU have a Hall sensor or a VR sensor?

[hoveringuy]

Crank is VR, cam is Hall.

[ahriley91]

Hall sensor.

[ahriley91]

Sweet! Thanks hoveringuy.

[ahriley91]

And another thing, do we have a PWM idle valve? I need to be 100% positive.

[nando]

yes, all BMWs use a PWM idle valve.

[matt]

Don't the M50 etc have an opening coil and a closing coil and PWM both of them?

[nando]

yes, it's a 3 wire PWM valve, pretty much identical to the one used on the M20. etas have a 2 wire valve.

[ahriley91]

Alright this is very useful. Nando, I was reading through your ms3 build on e30tech and on the 325ix site. What did you use for Q4 on the board? Because the guide says to use a TIP120/121/122 transistor. And did you install Y1? Because I didn't see it in the pictures. And does part of ms3x control the PWM?

[nando]

you don't need to build any of that stuff for MS3 with the MS3x. follow the MS3 build instructions on msextra.com (MS3 manual section), use the PWM outputs on the MS3x to control the idle valve.

I didn't build the V3.0 injector, coil, or idle circuits, Y1 is only for MS1. All you need on the V3.0 board are the proper jumpers for the crank input and E30 tach.

[ahriley91]

Thank you so much! They need to update the walkthrough then because it doesn't say any of that.

[nando]

it does but there are a number of build instructions depending on the version, and it's compatible with the MS2 build instructions so you may have read the wrong one.

http://www.msextra.com/doc/index.html#ms3

http://www.msextra.com/doc/ms3/build_manual.html

skip instructions that don't apply to the MS3x card. It really makes life easier. Other than jumpers, you don't need to mod anything.

Jumper as following:
JS9 to S12c
VRIN to TACHSELECT
TSEL to VROUT
JS11 to DB37 pin of your choice for the tach output (cluster) - I use one of the SPR1-4 pins, or the IAC pins (they aren't connected to anything unless you add a jumper).

always use rising edge (ignition input capture), and if using a the front crank sensor (ODB1 motors) tooth #1 is always 84 degrees, I think it's 60 degrees on the ODBII motors (internal sensor & wheel), but somebody like Matt will have to confirm.

you're also going to want to build a circuit to trigger the main relay, which you may have already seen.

finally if using stock M50 coils you need 6 BIP373 coil drivers wired to the MS3x spark outputs, but you don't need any resistors like the old MS spark outputs. Or find an LS1 based pencil style coil that fits in the M50 head and skip the external drivers.

[ahriley91]

Thanks so much. It helps a lot to ask questions from someone who's done this before.

[ahriley91]

So even with MS3X, I still have to have the six BIP373 coil drivers?

[nando]

Yes because the outputs are made for logic level coils like from an LS1

I think they are around 5 each, you dont need a resistor like the regular spark outputs