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GM O2 Sensor Testing

I have a scanner that allows me to monitor the voltage of each of the three o2 sensors. I brought my 97 blazer (V6 4.3L) up to operating temps and O2 sensors seemed to be very reactive. I tested the first two at idle speed approx .865V then at higher RPM dropps near to 0V. The third was the opposite I believe.

Does this mean that the O2 sensors are functioning properly? I was hopeing to try to boost my cars performance and mpg and I thought I'd start with the 02 sensors. Anyone have any suggestions?

Thank you very much!

Kory

Reply to
Kory.Kendziora
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Reply to
Woody

Thank you for the response.

My car has 106k on it and I don't believe the O2 sensors have ever been replaced. Is there a good chance that they are faulty?

Reply to
Kory.Kendziora

Your trucks OBDII computer will tell you if you have a failed or slow to respond sensor with a SES light and a code. But these codes are for major failures. Bosch manufactures oxygens sensors a recommends replacement every 50k miles. Maybe thats a little soon, but it couldnt hurt anything other than your pocket book. With over 100k your sensors are probably getting a bit slow but they still work. Looks like a judgement call to me.

Reply to
mobil_12

| Is there a good chance that they are faulty?

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Reply to
TE Cheah

As I stated if they were faulty the computer would throw a check engine light...

Reply to
Woody

You are looking at outdated information. Prior to OBDII sensors are recommended to be replaced at 50k. The sensors in OBDII cars are rated for well over 100K miles and only need replaced when the computer detects a problem and turns on the service light. To replace them prior to that is a waste of money. With an OBDii tester you can check the response time, voltage limits, heater current and just about anything else. There is no need to change them on a whim.....

Reply to
Woody

Thanks Woody.

I'll wait till i get an error code before I replace them. I'm still wondering where I can improve emissions... Damn 4.3L!

Reply to
Kory.Kendziora

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