[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index] O2 Sensor Diagnostics
My car has been surging for some time now, it's very noticable when the car is cold, less noticable when the car is warm. With the gas pedal in the same position and under constant load, the engine surges about every three seconds. So I took some readings on the O2 sensor. Here they are: It has 12 VDC to the O2 sensor (I take it this is for the heater) and the current goes from about 1.7 amps to 1.0 amps as the car warms up. The Bently says the current should increase, not decrease, as the car warms up. The green (signal? I guess) wire has 455 mVDC with it disconnected and the ignition on -- O.K. But when I pick a voltage off of it when connected to the sensor and the engine running, it varies from 0.8 VDC to 0.29 VDC at idle. If I then rev the car with no load on it, it changes from 0.08 VDC to 1.4 VDC. Seems like an awfully large change. My question: Is the O2 sensor toast and the ECU is changing the air/fuel mixture as told to, or is it something in the ECU and the O2 sensor is just providing feedback to what is actually going on? The car has 95K on it, I suppose it is the original O2 sensor. I know, you'll tell me to replace it. But I just thought I would ask first. TIA Paul 91 200q ************************************************************** Paul Waterloo TEL: (860) 267-7714 HydroAire Incorporated FAX: (860) 267-7387 875 Old Hartford Rd Colchester, CT 06415 EMAIL: 74543.407@compuserve.com **************************************************************
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