Originally Posted by Poolside
Great job, Roger!
I'm going to read your posts over more carefully when I get a chance.
You might try powering the heater in the LC-1 sensor from the ECU, you know, just like the narrow band heater. The ECU O2 sensor heater output is always on when the motor is running, and I don't recall but the heater may also be on whenever the ignition key is on.
The LC-1 may have a PWM heater control. If so, use the ECU O2 heater output as the high current input to the LC-1 heater supply. Note: 'High current' is a relative term here. An O2 sensor heater only uses about 16-18W or 1.25-1.50A
Had a good look at running the LC-1 heater ground, which is separate, to the Motronic heater ground but decided against it. With a schematic of both the LC-1 and Motronic, I might try; but without those, I don't want to take the risks of: damage, noise and ground loops.
The LC-1 may have a PWM (pulse width modulated) heater control.
I'm thinking about a 10 ohm resistor but one kit I saw suggested 20 ohms would work--still deciding.
Also working on some other circuit/wiring/filtering details on the Motronic's O2 sensor input.