Tacho wont work with COPS
 

hello everybody, I have fabbed up a loom and installed celica VVTI coil on plugs on the car. The tacho works fine with the stock ECU and COPS conversion.
when I converted to my MS1 PNP 9093MMD ECU (white and red) with the COPS the tacho stops working but tuner studio says the correct rpm.

So right now I have the factory ignitor and coilpack on the car and the tacho works fine.

I was told I need to run a wire from the ECU to the back of the tacho to get it to work correctly.
is this correct? ifso where do I connect it to the ecu?
going turbo soon so id like to prevent spark blow out before it will get tuned :)

if they are 4-pin coils and wired correctly, all you need to do is jump ig- and b+ with a 1K resistor.

thanks, ill try that. can I ask how this would make the tacho work?

because 90-93 miatas get their tach signal from the coils themselves and not the ecu.

ftfy

hello everybody, thread revival lol.
Just installed a 1k resistor bridging the B+ and -IG terminals in the diagnostic ports and it worked, decided to take it for a drive and the tacho stopped working again!
so I messed around with the resistor still got nothing.
Bought about 4 more resistors and still getting the same thing!

they are 4 pin coils, the MS1 picks up the rpm fine on tunerstudio.

anything else I can do?