Honda Car Forum

yet to chang my o2? o2 sensor and i will have a little increase in performance n throttle response what is the o2 and what does it do

Your 1993 has just one O2 (oxygen) sensor (1996 and up have two, one after the converter to monitor the catalytic converter). It is used to set the mixture precisely right. The Engine Control Computer guesses how much fuel to inject based on the MAnifold Pressure sensor (MAP) but that results in poor economy and poor power. The O2 sensor, mounted on the front of the exhaust manifold, provides feedback several times a second to keep the mixture exactly right. As the sensor ages it becomes sluggish. A new one will transition between rich and lean seven or more times a second, but as the sensor ages it slows down. Imagine trying to drive with a half second delay between turning the wheel and feeling any effect and you get the idea. It is often most noticeable when you change the throttle, like pressing it for a bit more power. The engine has to wait for feedback about the amount of fuel to inject at the new setting if the sensor is sluggish.































Early catalytic converter cars didn't have O2 sensors, but ran rich and injected air into the exhaust to burn the carbon monoxide. That gave catalytic converters a bad name because the fuel consumption was terrible and the power was significantly lower - just as a modern car is without a good O2 sensor.

Hi,

I've just done my own O2 sensor myself.
The O2 sensor/s is responsible for monitoring how much oxygen is left unburnt in your exhaust stream. Depending on your model (I haven't looked it up yet) you will either have one sensor down stream (just before your cat converter) and possible one up stream bolted to your exhaust manifold.
Will replacing your O2 sensor increase your engine performance? Yes, BUT it will not increase it anything measurable. What do I mean right? Well the O2 sensor connects to your on board computer (ECU) and tells your fuel injectors (in the most basic sense) how much fuel to add, to how much oxygen your engine is taking in, and using versus how much accelerator your using. So if your O2 sensor has aged, which it will over time (you'll want to replace it every 100,000 km's generally) then it will not accurately tell your ECU how much unburnt oxygen is in your exhaust gas and so your injectors may not be giving you the right amount of fuel.
So: in all Hondas over 1990 the O2 sensor is connected to the ECU and when they fail then a check engine light will come up on your dash board. If this hasn't happened yet then your O2 sensor has not yet catastrophically failed, but may be fairly close to it if you've got a fair amount of mileage on the clock. Replacing your O2 sensor will only help your ECU to deliver the fuel required for your use up to its programming. You will not magically gain 5hp by putting in a new one (that is unless your O2 sensor is dead and your engine is now completely de-tuned -due to an erroneous ECU caused by the dead sensor- and performing 5hp below what it should be).

• In my case my sensor failed
• I was chugging through fuel very very quickly
• the failure was flagged by the ECU and so gave me a warning light
• the warning light prompted me to check the error codes
• the O2 sensor was in error
• I cleared the code and re-drove the vehicle to make sure it was in error
• the light came on again
• I checked the code and it was the same
• I pulled out the old sensor
• wired in the new one
• and now my car isn't taking massively more fuel to drive around.

So my performance increased after putting in the new sensor, but only back to what it should have been.