So I've got a '01 VVT motor in my '93 and it's running great. I'm using my old 1.6 CAS to send signals to a DIYPNP and the NB sensors to a VVTuner. Completely separate from each other.

I want to eliminate the CAS altogether, the other day I tried to cheat and split the signals going to the VVTuner at the ecu and connected them to my DIYPNP, changed the settings in TS for a 99+ motor, and unplugged the CAS and it wouldn't start, so I said to hell with it and put everything back the way it was.

Do I really need to use the output from the VVTuner to send to my ECU? I figured since it was pass through anyway, it shouldn't matter, and I should be able to use NB sensors with the DIYPNP even without the VVTuner, no? I also tried splitting ground from each sensor to the signal ground wires (black/green stripe) going to the ecu.

 

send the NB sensor signals to the DIYPNP as well and remove the CAS.

 

That's what I thought I did by jumping the signal and ground wires at the ecu. Essentially, I have shielded wire running inside the car from each sensor, then split the signal and ground to the ECU and VVtuner, with the power for the sensors coming from the VVTuner only. I followed the settings on the DIY site for 99-00 Miata. Maybe I have something set wrong, or my grounding is off.

 

Where did you ground your shields?

 

I have them grounded to pin 11 on the VVtuner. I used three conductor (plus shielding) wire made for strobe lights with the power ground and signal wires connected solely to the VVTuner as per the diagram on DIYs site.