markwilliam1 Posted November 19, 2016 Share Posted November 19, 2016 Although my Check Engine Light has never come on and Grannie (1985) runs smooth my O2 Sensor is original. 31 yrs old. 36K miles. 22RE. Should I replaced it anyway? Trying to think of anything to improve performance and mileage! Nothing indicates a bad sensor. It's pretty old though. Thanks! Â Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted November 20, 2016 Share Posted November 20, 2016 I would not change it. Â Quote Link to comment Share on other sites More sharing options...
WME Posted November 20, 2016 Share Posted November 20, 2016 NO touch... Quote Link to comment Share on other sites More sharing options...
Jaunt Posted November 20, 2016 Share Posted November 20, 2016 After I bought mine I brought it back to CO and had to get emissions tested and it failed horribly for HC and CO, Also I was getting like 10mpg. No check engine light but after some doing some diagnostics I found my o2 sensor was stuck lean causing the engine to run super rich.  Replaced with a new Denso unit and passed emissions with flying colors.  Fuel mileage went up as well.  With that said if yours is running good i'd leave it, you could verify proper operation of the sensor with a volt meter if you have one.  With pre OBD2 engine management you can't rely on the check engine light for anything.  Quote Link to comment Share on other sites More sharing options...
markwilliam1 Posted November 20, 2016 Author Share Posted November 20, 2016 Thanks for the responses! She is running good but I'm trying to improve mileage. Was going to get the Toyota OEM 02 sensor as a replacement but it seems not necessary according to you "experts" which I'm not! Lots of time now to think of Toy improvements as she's in storage for the winter. Quote Link to comment Share on other sites More sharing options...
Maineah Posted November 21, 2016 Share Posted November 21, 2016 2 hours ago, markwilliam1 said: Thanks for the responses! She is running good but I'm trying to improve mileage. Was going to get the Toyota OEM 02 sensor as a replacement but it seems not necessary according to you "experts" which I'm not! Lots of time now to think of Toy improvements as she's in storage for the winter. Do you own a DVM? If so disconnect the O2 sensor connect one lead to the sensor wire the other to a good ground. Start the engine the voltage will be between 0 and 1 volt It does not matter what it reads but it matters how active it is it should be all over the place. 1 volt is rich 0 volts is lean. This is how it works the voltage is not constant it changes as the ECU decides on the  mix over time in a prefect world it would be  a systolic mix the O2 sensor sends information back to the ECM so it can compensate. Even a dead sensor will not have a dramatic effect on fuel economy but every bit helps. If it's active don't worry but if it is lazy or stays at one voltage replace it. Bosch and others make compatible O2 sensor it's not rocket science they have been around for a long time Toyota did not make them any way the OEM was most likely Bosch. Quote Link to comment Share on other sites More sharing options...
markwilliam1 Posted November 21, 2016 Author Share Posted November 21, 2016 Thanks Maineah! Good advice and I'll test it in the Spring. Was hoping a new one would improve my mileage through! Quote Link to comment Share on other sites More sharing options...
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