O2 sensor operating range?
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From: OK
O2 sensor operating range?
In troubleshooting my idling problem I checked the voltage on my O2 sensor (ECM in test mode, O2 lead to ECM grounded, 2000rpm per the manual) and I'm getting around .88 volts. The manual says the minimum should be .8 but I'm wondering just how close the tolerance is. Is .08 considered a significant amount above the .8 limit or am I 'borderline' here?
Thanks in advance for any help!
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Original owner - '84 T/A w/stock 305HO 5-speed
Thanks in advance for any help!
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Original owner - '84 T/A w/stock 305HO 5-speed
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DT,
You may presume that the oxygen sensor is still functioning, and that it may be correct. It seems to me that as a sensor fails it tends to report leaner numbers (lower voltages) instead of a rich indication. If yours is failing, it isn't failing in the common mode.
Understanding this, you probably have a rich condition, and should be able to tell by other symptoms, such as spark plug condition, exhaust odor, fuel consumption, operating temperature, and performance.
Since your '84 came with a Rochester E4ME, my first suggestion would be to check the mixture control solenoid adjustment. The duty-cycle rate of the solenoid is a good indication of what the ECM interprets as idle fuel mixture. If the other symptoms confirm this, try adjusting the mixture control cycle rate to the lower end of the range, and verify a correct TPS voltage (0.48VDC on your engine).
This is all under the assumption that the air filter is clean, the PCV is clean and functioning, the EGR is clean and operating without sticking, and the EVAP canister is not flooded and/or the canister purge valve is not stuck open.
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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0
You may presume that the oxygen sensor is still functioning, and that it may be correct. It seems to me that as a sensor fails it tends to report leaner numbers (lower voltages) instead of a rich indication. If yours is failing, it isn't failing in the common mode.
Understanding this, you probably have a rich condition, and should be able to tell by other symptoms, such as spark plug condition, exhaust odor, fuel consumption, operating temperature, and performance.
Since your '84 came with a Rochester E4ME, my first suggestion would be to check the mixture control solenoid adjustment. The duty-cycle rate of the solenoid is a good indication of what the ECM interprets as idle fuel mixture. If the other symptoms confirm this, try adjusting the mixture control cycle rate to the lower end of the range, and verify a correct TPS voltage (0.48VDC on your engine).
This is all under the assumption that the air filter is clean, the PCV is clean and functioning, the EGR is clean and operating without sticking, and the EVAP canister is not flooded and/or the canister purge valve is not stuck open.
------------------
Later,
Vader
------------------
"Make Me Bad"
Adobe Acrobat Reader 4.0
Thread Starter
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Joined: May 2000
Posts: 326
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From: OK
Agreed- I'm going to go ahead and run the manual's performance system check and just start from there. I had wanted to check the o2 sensor because I had a similar problem happen before where the sensor was the culprit. The O2 sensor I have now I've been running with for about 8 years, so I was suspecting that it might have gone out on me.
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