Can't get rpm to work with jimstim
 

I have finally finish my ms2 3.0 board (running on extra(setting it up for my 94 miata)) and hooked it all up to my jim stim. I can not for the life of me get the rpm to work it just sits at 1 rpm.

On the jimstim i do have 2 and 3 fliped on and the tach jumped on the board

I used these instructions to set up for the cam sensor

5.2.3
a) Solder a link between VRIN and TACHSELECT
b) Solder a wire between VrOUT and TSEL
c) Install a 1k resistor (any value 470R - 2k2 is likely OK) in the proto area. Connect one end to the 5V hole and
join the other end to VRIN with a jumper wire.
d) With a small screwdriver, turn the pots, R52 and R56, about 12 turns anticlockwise (sometimes you may feel
a "click" when the end position is reached, they can't be damaged by turning too far.) and then turn R56 back
about 6 turns clockwise.

5.2.14.2 Adding a cam sensor input - hall sensor / optical sensor
This option uses the spare opto-isolator on the mainboard for the cam input and matches the polarity inversion
of the VR/universal tach input.
This section is for open-collector sensors as covered in 5.2.3 that ground switch only.
a) The OptoIn pad should be connected to a spare pin on the main DB37 connector (e.g. SPR3)
b) Connect OptoOut to JS10 (ensuring that nothing else is connected.)
c) Jumper XG1 - XG2
d) Check that R12 is a 390R to 470R resistor, replace if not.
e) Install a 470R 1/4W resistor on the proto area to +5V.
f) Jumper the other end of the 470R resistor to OptoIn (joining the jumper wire there.)
g) Ensure that C30 is not fitted.

Does this all sound right or is there something completely wrong?

You're following generic instructions and not miata specific ones.

I wouldn't expect it to work if you followed either/or of those methods above.

you could do both 5.2.3 AND 5.2.14.2 but use vrOutIinv instead of vrOut.
I'd also use IAC1A instead of Spare3 like suggested. That's the pin most people use, so it helps you standardize your install a bit.


or you can do this:

https://www.miataturbo.net/attachmen..._0003_mods-jpg

You also have to make sure your stim is correctly setup for the 2nd trigger and inputting into the correct pin on your Db37.

Thank you so much for helping!

I will probably go with this miata set up since well it sounds like it works lol. Only question is for the yellow wire. are you just dropping IGN and IAC2b on the proto area?

oh a second question i don't really get where i am soppose to jump the 2nd tach signal?

this will explain: Megasquirt 2 Assembly - Miata Turbo FAQ

thank you

ok one last question i am running the 4 channel ignition/injection driver board so i wouldn't have to worry about the yellow wire right??

no. those were just a standardized method of building a MS2/harness.