CNG changeover switch powers the three solenoid valves on reducer, monometer and Advancer/Emulator simultaneously. Changeover switch is connected with Ignition coils, so once it senses that ignition coil is receiving power or transmitting signal then with slight delay it simultaneously provides power to the solenoids, Advancer/Emulator, Monometer and stops the power to injectors through its own wiring harness. If conversion fails because of engine not receiving gas then engine shuts down, Power to ignition coil disconnects and power to solenoids, monometer and advancer/emulator is withdrawn.
What you are saying is, even though power to injectors are restored but somehow Advancer/Emulator still remains on and keeps on sending the signal originally meant for CNG to the ECU.
- This can easily be checked by measuring the volts on solenoid valve, looking below into advancer/emulator lights such as if it is still receiving power even on petrol.
Anyway, advancer/emulator turns off on petrol, it does not control injectors timings as its only function is to stop injectors once powered on and restore the power to the injectors once advancer/emulator is turned off.
I will look into the possibility of wrong cng wiring and I already have a brand new spare TL advancer/emulator with me which I will try on this.