Quote:
Originally Posted by tony_fury
Since your bypassing it anyway, couldn't you just put a 1M ohm resistor across the O2 leads, this should eliminate the CEL..
O2 sensor bypass
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I should caveat my post.
I found this circuit on the Internet and not certain if this circuit would work on your P-car. I take no responsibility for this.
I have no experience with this type of mod on the O2 system of a car. I have experience bypassing O2 sensors on motorcycles, but not using the circuit that I posted the link to. I used strictly a resistor and for the life of me, I cannot figure out why they would use a capacitor in parallel with the resistor.
This combination of resistance and capacitance in parallel is known as a RC tank circuit. The capacitor will act as a charging tank, while the resistor will drain the charge.
It will provide as a great voltage filter in this scenario.
The oxygen sensor is positioned in the exhaust pipe and can detect rich and lean mixtures. The mechanism in most sensors involves a chemical reaction that generates a voltage drop. (Resistance variable)
The engine's computer looks at the voltage level 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.
By bypassing the O2 sensor and providing a set resistance, you are essentially fooling the computer that the AFR is at this level always. It is only providing a fixed voltage drop.
Here is a good read on what the O2 sensor does.
how an oxygen sensor works
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