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Old 20 June 2016, 01:12 PM
overyonder overyonder is offline
Join Date: 03 March 2010
Location: Charlotte, NC
Posts: 2,111

Originally Posted by Malmensa View Post
Most modern cars are closed loop and will determine from O2 sensor info how much fuel to meter, but some older cars have no O2 sensor.
I think you're mixing O2 sensor versus MAF (mass-airflow sensor). The MAF measures the amount of air flow into the engine (and sometimes the temperature of the air charge) and adjust the amount of fuel based on that. The O2 sensor is more to verify that the fuel charge is burnt cleanly to make sure the engine is not running lean or rich. Yes the O2 sensor can help the PCM adjust fuel amounts, but it's mostly to adjust the timing.

It's really a "Big Dance" that the PCM takes inputs and determines what to do from there.

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