tach signal

Not sure if I am following correctly. Let me step back and ask some questions to make sure I offer the correct answer.

When set to 1cyl mode, does the tach learn and work correctly?

If you are using standard tach mode, which is usually 6cyl/8cyl on most remote starters that have these program options, then hooking that 6/8cyl input to a 1cyl wire will never learn correctly. Its missing 5-7 more pulses. It thinks only one cylinder out of 6/8 is actually running which is obviously not enough to run a 6/8cyl engine. Therefore it will not accept this as a valid input.

Again if I read correctly you had it hooked to a 4cyl engine on ONE cylinder's injector wire meaning ONE cylinder's injector pulses are being monitored, meaning the remote start must be set to ONE cylinder in order to understand why the pulses are spaced farther apart. It can then interpolate this speed as one of 4 cylinders internally, and comprehend that the engine is indeed running even though it only sees ONE cylinders pulses.

I hope I have understood your situation correctly, and helped you understand.

Oh my info says there is a black wire, and a yellow/red at the coils on the left side of the engine that give you a 2cyl pulse each. You can find a 4cyl pulse at the ECM behind the passenger glovebox and that is a BLACK/ orange wire. Sometimes there is also a black wire on the OBDII plug that gives you 4cyl output as well. It will be located on the end of the connector all by itself if present.