Logged O2 Voltages, Simulator Possible
02-19-2005, 04:09 AM
#1
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Logged O2 Voltages, Simulator Possible
My generic OBD2 software was stating it was reading only about 2.3 Hz but it was certainly gathering data quicker than that. There was enough resolution to determine it is very feasible to fool the ECU using the existing signal.
Below is a portion of the entire plot showing the Primary and Secondary sensors on Bank 1. Also below that is a link to download the Excel sheet if you want to see the whole plot. There are macros in the workbook but don't worry, they are not some computer killing script. They just allow pan and zoom functions on the plot.
Looking at the data it is obvious a low pass filter is all which is needed. The question is if I can make it with a high enough impedance so as not to affect the original signal. I'll being swinging by the week to pick up factory connectors to make this a true PnP.
I will need to enlist someone's help though. I need someone with DPs to move their secondary sensor back before the main cat and test the simulator. I haven't put on my self made piggies and don't know when I will get the time soon. With the factory connectors, you would simply unplug the appropriate connector at the firewall, install the simulator and plug the sensor into the other side. In other words, the sensor has to remain.
<img src="http://www.flwse.com/images/steve/Audi_Tech/O2Sim/Audi_O2.JPG">
<a href="http://www.flwse.com/images/steve/Audi_Tech/O2Sim/AUDI_O2.xls">Logged O2 Voltages in Excel</a>
Below is a portion of the entire plot showing the Primary and Secondary sensors on Bank 1. Also below that is a link to download the Excel sheet if you want to see the whole plot. There are macros in the workbook but don't worry, they are not some computer killing script. They just allow pan and zoom functions on the plot.
Looking at the data it is obvious a low pass filter is all which is needed. The question is if I can make it with a high enough impedance so as not to affect the original signal. I'll being swinging by the week to pick up factory connectors to make this a true PnP.
I will need to enlist someone's help though. I need someone with DPs to move their secondary sensor back before the main cat and test the simulator. I haven't put on my self made piggies and don't know when I will get the time soon. With the factory connectors, you would simply unplug the appropriate connector at the firewall, install the simulator and plug the sensor into the other side. In other words, the sensor has to remain.
<img src="http://www.flwse.com/images/steve/Audi_Tech/O2Sim/Audi_O2.JPG">
<a href="http://www.flwse.com/images/steve/Audi_Tech/O2Sim/AUDI_O2.xls">Logged O2 Voltages in Excel</a>
02-19-2005, 06:28 AM
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Remember to put in a heater load resistor too
I'm pretty sure the ECU will detect if the heater circuit is open. You'll probably need to include a large wattage resistor to simulate that load.
Thanks for sharing your research - been thinking of doing the same thing myself.
Dave
Thanks for sharing your research - been thinking of doing the same thing myself.
Dave
02-19-2005, 06:35 AM
#6
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The sensor remains in place,
So the heater circuit is still functioning.
I am basically just putting a device in series to alter the O2 voltage signal. Of the four wires in the factory wiring, only the signal lead will be touched, all others will remain the same.
I am basically just putting a device in series to alter the O2 voltage signal. Of the four wires in the factory wiring, only the signal lead will be touched, all others will remain the same.