I have been reading about oxygen sensors and their purpose/function. I have come up with an idea and I am curious to know if anyone has thought of this or tried it? According to the manual a properly functioning Heated Oxygen Sensor should carry a resistance of 5 - 7 ohms at 68 degrees. So my question is this, would it be feasible/beneficial/etc. to determine the range of resistance that would offer peak performance and simply eliminate the Oxygen sensor by wiring in a resistor with the correct resistance in order to achieve peak performance, thereby eliminating the need to replace an expensive part that will simply wear out again in time? Thoughts/comments would be appreciated and anticipated.

Brad Schmidt

 

*Subscribes*

Interesting theory. I wish I knew more about how that system worked.

 

I'm right there with tacoclimber, i wish i knew more but this is what I found.
Sounds like the best thing is to just have an O2 that works, since it automatically adjusts the computer for optimum performance. I think if you just had a constant resistance that didn't adjust accordingly it would cause more problems...

"The mechanism in most sensors involves a chemical reaction that generates a voltage. The engine's computer looks at the voltage to determine if the mixture is rich or lean, and adjusts the amount of fuel entering the engine accordingly. The reason why the engine needs the oxygen sensor is because the amount of oxygen that the engine can pull in depends on all sorts of things, such as the altitude, the temperature of the air, the temperature of the engine, the barometric pressure, the load on the engine, etc. When the oxygen sensor fails, the computer can no longer sense the air/fuel ratio, so it ends up guessing. Your car performs poorly and uses more fuel than it needs to."

 

Makes sense to this shadetree mechanic...

 

On my Dad's older Porsche 911 when the oxygen sensor went bad the mechanic either did this trick or just removed it because they were so expensive. I am not sure which but it still ran great. They only problem it had was that it would hunt for the correct idle speed when it was cold.

Sometimes it was annoying because it would die when you pushed in the clutch when you came up to the end of the drive way. Once it warmed up it was always fun to drive though.

 

Yeah, I think there are too many intangibles to have a constant resistance.

 

I have been searching for a way to understand how the O2 sensor plays a role in the mixture. When the O2 voltage is low the computer increases the injector time, right? So why doesn't the O2 go to .45VDC once the mixture is richened? Why does my O2 stay at .20 VDC all the time at idle? Thanks all of you. Yotatech has the best forums.

I also have noticed if I run at 2500 RPM while standing still after 2 minutes the O2 sends a code. Even with a new sensor just installed. I have LC Engineering header and the O2 is back by the cat. Maybe the O2 is getting too hot. Any ideas?


1985 22re

 

I dont know what year yota you have but the ones with o2 sensors have voltage that switches up and down in a normally functioning engine. The o2 sensor AFTER the cat should be very close to flat line voltage wise. If you have a #2 o2 sensor that has voltage mirroring that of the #1 sensor, that tells you the cat is no longer working properly. Now vehicles with air/fuel sensors should have voltage that should be as close to .33v after the engine is warmed up as possible. They do not deviate like o2 sensors. The #2 sensor in those vehicles are still o2 sensors

 

something like this?
http://www.hackaday.com/2006/11/14/o2-sensor-simulator/

http://www.bobblick.com/techref/proj...sim/o2sim.html

 

Good try, but it won't be an improvement. You want the dynamic adjustment to the air/fuel ratio that the computer age has provided. The ECU uses the front O2 sensor for feedback on the A/F ratio which changes with different temperatures, elevations, tuning changes, fuel blends...etc.... A static "one tune fits all" would not be an improvement over the current ECM system, it would be a step backwards about 30-40 years.

Now there are piggyback computers available that will let you fine tune the A/F ratio more towards performance and away from the fuel saving, smog reducing, stoichiometric ratio programed into your ECU. And some of these work by modifing the signal from the front O2 sensor, but the O2 sensor still needs to be there or there won't be a signal to modify. The O2 sensor is your friend.

I installed a wideband O2 sensor and gauge for helping tune my piggyback controllers. So I actually have 3 O2 sensors now LOL.