Can you measure the voltage at pin 2? In theory the trigger voltage should be 1/3 of 12V or about 3.6V. What I am trying to do is get the rest voltage (with no pulses from the coil) 1 V or so higher than the trigger voltage so it should trigger with 1 or 2 V less from the coil. Its possible that the trigger voltage isn’t doing that for some reason (such as the trigger pin is drawing current and lowering the voltage which I don’t think it should be).
Peter