Build your JimStim according to the build manual. It’s really very simple to build, so I’m not going into it here.
If you buy one, make sure to get the three-dot version. Matt from DIYAutoTune confirmed that the wheel pattern for the ’99-up Miata was changed between the two-dot and three-dot versions of the JimStim. The two-dot processor had the wrong pattern and won’t generate an rpm reading in Megatune.
Preparation of the JimStim is easy.
- set dips 2,3,6 to ON and the others OFF
- install a jumper from PIN25 (IAC1A) to the 2nd TRIGGER header pin (yellow in the pic below).
Edit: I got a three-dot chip and the Miata 99-00 mode is still not functional. So, if you don’t get an rpm reading on the JimStim, don’t worry too much about it, just try a different mode for now, like CAS4/1 or Edis. I got mine functioning on CAS4/1.
This is only on the JimStim of course. Once you plug it into the car, you’ll obviously have to set the Tach input to Miata 99-00
You can test the functionality of the outputs like this:
- FANS: run 2 jumpers to IAC1 led. 1st one from 12V (black in the pic), 2nd one from SPR1 (red in the pic)
- VICS: run 2 jumpers to IAC2 led. 1st one from 12V (black in the pic), 2nd one from SPR2 (green in the pic)
- ALTERNATOR: run a jumper from IAC1B to one of the 6 IGN leds (blue in the pic). Raise the input voltage of the JimStim. When it goes over 14.3V, the led will light up (dim).
