When we were done, the A/C still worked, the idle valve would compensate for the AC being on or off, the engine could start with the A/C on or off with no throttle input, and the car had great drivability. We were also able to control the VICS system successfully,
The DIYPNP unit fit great in the stock location:
![Image](http://diyautotune.com/diypnp/apps/n76/images/99_miata_diypnp_mounted_02.jpg)
The owner of this 99 Miata also requested the sequential fuel injection upgrade. This is a simple plug-in card with a few jumper wires to run to give full 4-channel sequential fuel injection when using the MS2Extra 3.0.3 code.
![Image](http://diyautotune.com/diypnp/apps/n76/images/99_miata_diypnp_seq_01.jpg)
One very important note on a difference in this 1999 than the previous 90 to 97 models is that the voltage regulator for the alternator is inside the ECU. We were able to build a circuit inside the DIYPNP in the proto area to regulate the voltage. A complete writeup with pinout, specific details, a basemap, and the voltage regulator circuit diagram is available here:
http://diyautotune.com/diypnp/apps/n76/ ... bp-mt.html
Russ Patrick
DIYAutotune.com Technical Support