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Old 01-07-2013, 02:20 AM   #26
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Join Date: Apr 2010
Location: SD, CA
Posts: 261
My Ride: M3
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More information on the 02 sims

Hey Eugene,

Just found this thread. thanks buddy!

LEGAL NOTE: These are solely for "off road use" if you plan on using them to pass emissions, your accountable, and I'm not responsible for what you do with the 02 emulators. I will just be responsible for the emulators to do their job and work as described.

More information on the 02 sims:

HOW do they work?

When attempting to simulate a post 02 sensor or down-stream sensor, there are two areas that need to be emulated; the voltage the ECU sees ranges from .1v (lean) to ~.9v (rich) the second area is heater part, thats built-in to the 02 sensor (used to accurately read the Air/Fuel ratio or AFR)

What I have done is used a resistor and capacitor to show the ECU a consistent voltage (.415v) witch seams to keep the ECU happy and keep the car in open-loop right before the closed-loop mark (.45v) so logically speaking the car stays at a perfect balance between rich and lean ~ 14.7 AFR. This method I found out was a hit or miss, as the spark plug defouler method.

A more complex circuit would need to be built so the ECU does not flag the consistent voltage. This would call for a oscillating signal generator, that would oscillate the voltage signal from .11v to .81v greatly mimicking what a typical working post-cat 02 sensor should be doing, and in-turn, keeping the ECU happy.

For the heater, I now put a large military-grade resistor in-line, between the heater wires of the 02 sensor, keeps the ECU from throwing a fault for the heater sensor.

how do I order them?

Since I do this on the side, and haven't found a vender to produce 02 sensor connectors, there will be 3 ways to go about it:
1. Send me both post-02 sensors ( I cut them 2" from the sensor, then include them when shipped back)
2. Cut off 2-3" from the connectors (see attached diagram)
3. You don't send me anything, I just make the 02 sim (with leads) and you hard-wire it to the 02 sensor wires.

Please note for number 3: You will need a multimeter to find the polarity in the same color wires(white) or follow wires to the correct color at the other end of the connector. Also if the polarity is not correct, the 02 sim can be fried!

PM me if you would like to order them!

ABOVE is a video of live data (on BMW e46) showing the difference between the more complex slim oscillating (02B1S2) for Bank 1 sensor 2. The simple, consistent voltage (02B2S2) for bank 2 sensor 2.
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Without Failure There is No Success

Last edited by bimmerguy055; 01-07-2013 at 02:27 AM.
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