DIYPNP no start, no rpm
 

Hi all,

I recently built and installed a DIYPNP for my 91 miata, got it running, drove around for about a week, then decided I wanted to set up the launch control. I opened up my ecu, soldered in the wiring for the clutch switch, put everything back in, and it ran fine first try. However, after trying to start the car again it would just crank and not start. Following this, the car started a couple more times, but now I'm at the point where the car just cranks without starting no matter what.

While cranking, there is no rpm being displayed on the dash or in tunerstudio, however the few times the car started both these were working. No rpm on the dash lead me to believe it was something wrong with the CAS. When I check the voltages at the cas connector, the pins are at 0v, 12v, 0v, and 3.8v. From what I understand, it should be 0, 12, 5, 5. The voltages read the same when testing directly from the ecu pins.

Interestingly, when the ECU is plugged in to external power via the barrel jack, the pin that reads 0v instead of 5 when connected to the car has voltage.

Did I short something in my board? If so, what should I do from here?

Here's a log while cranking