MS3+MS3X Stopped working - No Cranking/RPM Signal
 

I have been running an MS3 with MS3X (built using Franks guide) on my JDM 1992 Eunos Roadster with minor mods for a few weeks with no problems (really enjoying it!) but recently it simply stopped working. I came to my car in the morning and it just cranked and didn't start - it was working absolutely fine the night before when I parked it...

I reverted the car back to stock and it ran horrifically! Misfiring, smoking, sputtering, running super rich then lean and stalling - completely undriveable but after swapping in a different CAS it runs fine stock but still doesn't run with the MS3.

Tuner studio detects the correct throttle position, temps, pressure, but I'm sure it used to detect the car being cranked - nothing now - just a change in MAP.

High speed loggers show a CAM signal but no CRANK (and hence no SYNC/RPM) so I checked that the pots on the VR circuit are still tuned which they are (I can't see how they would change overnight) and visually inspected the board for any obvious damage (nothing).
https://www.miataturbo.net/attachmen...ine=1397790548

I have attached a log from when it was working and a log and composite log from when it failed to start. My msq (attached) has not been changed between the working and non-working state.

Really at a loss as to how it could stop working overnight - the only thing I can think of is that it overheated as I was using the heater on high in the foot-wells that evening...

PS - Not sure if it matters but I've also posted this question on MSEXTRA forum.

Go another full turn on the R56 and see if that gives you the signal back.

You were right!
 

Exactly as you suggested, I did one full turn anticlockwise on the pot and got the signal back. The car started right up and runs great again.

Back to tuning for me.

Thanks!