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, Thu, 27 Oct 2005 05:21:03
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If you see a voltage swing, it does mean a lot of things are working right but the ECU creates the voltage swing you are measuring with the meter, not the O2 sensor. You can yank the O2 sensor and the voltage will still swing at the connector. Artifact or not, thats what you are looking at when you measure the O2 sensor output with the sensor connected and the car warmed up.
If you hook a meter up to the connected sensor with clamps so you can start a cold engine and watch the output as the engine warms up, you can watch the warm up cycle in terms of that voltage. Only after the car has run a few minutes does the "swing" start.
With my bad AMM, and the O2 sensor connected, the voltage would jump to .8 volts and stay there for a few seconds after start then lean down and the voltage would drop and the car would stall. After a couple tries the car would continue to idle but you could watch the voltage continue to decay down slowly to .02-.03 (yes .zero 2 (sensor connected)) volts in a very linear fasion until the car warmed up and the O2 circuitry in the ECU came on line and started the swing. Before that is the only time you are reading O2 sensor output alone with the sensor connected, if then.
With the new AMM the reading stays rich and the until the O2 circuitry comes on line and then starts to swing. But you can have a bad but still working AMM and no O2 sensor and still get a voltage swing so using that swing to say your O2 sensor is working is a mistake in my opinion. It does say that the fuel adjustment protion of the ECU is doing something, or at least trying to.
I don't claim to understand it, I'm just sharing what I have observed and measured repeatedly and what caused me so much confusion. Maybe a low voltage is put on the connector from one part of the ecu and then compared to the O2 sensor voltage and then a high voltage and then the O2 sensor voltage. Who knows. My only real point here is that the swing has nothing to do with the O2 sensor "wellness" and if you want to know if its doing anything you need to disconnect the black lead and check it alone, by blipping the throttle or crimping the FPR vaccuum line and watching the output voltage to see if you can make it move within its range.
posted by 216.23.59...
, Thu, 27 Oct 2005 05:21:03
, Thu, 27 Oct 2005 14:33:55
, Thu, 27 Oct 2005 10:43:13, Thu, 27 Oct 2005 18:37:39
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