My question (finally) is: what O2 sensor output range is considered = normal with the ECU adjusting things? I thought that the O2 sensor / = ECU combination attempts to adjust for no excess oxygen or a 0.00 = voltage
--------------------------------- 0.450 volts is about 14:7 Air fuel ratio, or stoichiometric. So you want to see about 1/2 volt, not zero volts. Someone will correct me if I'm wrong about the exact numbers. I too have spent many months monitoring the O2 sensor. In my case it is to adjust the propane fuel system on my van. Anyways, on gasoline I find that it moves between 0.500 - 0.800 volts in closed loop. I have wondered if it is on the rich side. The digifant seems to fluctuate in a very wide band, and be very erratic compared to other vehicles I have monitored. My 1986 Jetta CIS-E moves between 0.400 - 0.600 volts. OBD II Japanese cars are tighter. I find that I can lean the propane system right down to 0.050 volts (almost 16:1) at highway speeds with only a small reduction in power. Fuel consumption does not seem any better so theres no point. Some emissions may be off the chart at that ratio though. EGT is the same or slightly cooler by about 100 degrees F on propane So going very lean on propane does not seem to affect cylinder head temp/EGT. Another observation, O2 sensor output voltage on propane without feedback is very stable, moves very slowly compared to gasoline. I can't wait till there is a better (cheap for DIY) way to measure Air Fuel ratio. I don't find that the oxygen sensor - voltmeter way is telling me all that I want to know. The UEGO sensors and infrared meters are too expensive as far as I know. With tighter emissions requirments every few years, I'm sure something will trickle down. Also, I have Gary Lee Calgary |
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