I'm doing a search and I've noticed that ALOT of people think its just a dancing light that does nothing... Hopefully this quote will clear a few things up.
The OEM O2 sensor is a "narrowband" sensor; it only does the small job it has to do. This job is to tell the ECU when it is lean or rich; not how rich or lean, just a general idea. It does this job, and it does it well. If you hook it up to an a/f gauge and it says the car is running lean, then it is running lean. If it says it's running rich, then it's running rich.
The reason it does not work well in high-performance cars is that the range you want to keep the a/f ratio at is usually not at 14.7:1, it is usually lower. Therefore, when you try to tune it at a lower ratio, it gets very inaccurate. Whether it be 13.0:1 or 8.0:1, the guage and sensor will only read rich.
One thing you have to think about is this: the gauge only reads what the sensor tells it; no more, no less. If the sensor was NOT doing its job, then your car would run like crap from the factory. But it does do its job; people just don't like the fact that it doesn't do anything more than necessary.
So the point I would like to make is that an a/f gauge on the stock O2 sensor is NOT worthless; it WILL tell you if you're running rich or lean. But it will NOT help you very much at tuning, especially if you are running much higher HP levels than stock.
The OEM O2 sensor is a "narrowband" sensor; it only does the small job it has to do. This job is to tell the ECU when it is lean or rich; not how rich or lean, just a general idea. It does this job, and it does it well. If you hook it up to an a/f gauge and it says the car is running lean, then it is running lean. If it says it's running rich, then it's running rich.
The reason it does not work well in high-performance cars is that the range you want to keep the a/f ratio at is usually not at 14.7:1, it is usually lower. Therefore, when you try to tune it at a lower ratio, it gets very inaccurate. Whether it be 13.0:1 or 8.0:1, the guage and sensor will only read rich.
One thing you have to think about is this: the gauge only reads what the sensor tells it; no more, no less. If the sensor was NOT doing its job, then your car would run like crap from the factory. But it does do its job; people just don't like the fact that it doesn't do anything more than necessary.
So the point I would like to make is that an a/f gauge on the stock O2 sensor is NOT worthless; it WILL tell you if you're running rich or lean. But it will NOT help you very much at tuning, especially if you are running much higher HP levels than stock.