cardsrule

Does anyone know if its easy to add a o2 sensor to a efi system with a autronic SM4? Would i have to add a controler? I want to start driving the car more on the street and would like to run close loop. Is this a good idea or just a waste of money?

Thanks,

Scott

Speed Lab

With Autronic SM4 you can run closed loop with a simple 4 wire heated oxygen sensor. You need the blue wire to SM4 pin 37 and a sensor ground wire, also for the sensor heater you need battery power (12v) with an independent ground wire. The closed loop function is activated in the Autoronic configuration software. You may need to tune the O2 feedback controller parameters to get it just right. The fuel map needs to be tuned very close to stoichiometric A/F ratio for all closed loop sites. Also the sites for closed loop operation must be set to 14.7 in the Target A/F table. Let me know if you need help.

The only reason to ever run closed loop with a simple O2 sensor is to allow operation of a catalytic convertor. Don't operate a catalytic convertor without one. The O2 sensor was invented because of the invention of the catalytic convertor - no other reason. Of course different discussion for use of a wide band exhaust sensor.