04-08-2005, 12:50 AM
Hello, I was just thinking about some post that I believe fordfaster made a while back, on how if you tune your fuel to a certain air/fuel ratio, the car just eventually cancels out the changes you made by re-learning it back up to stoich... What I was thinking, you know how you basically interupt the MAF or MAP sensor signal and trick the ecu to runing more rich or more lean? What if you did this with the o2 sensor as well, therefore instead of your ecu re-learning itself back up to 14.7 you could trick it to thinking that its there, when its really at some user selected value. So for example on the o4's, the wideband o2 sensor puts out a 0 - 5 volt signal to the ecu telling it what the air/fuel ratio is at, you have something read in the o2 sensor signal, raise or lower the value (just like an AFC does to MAF/MAP signals) then output it back out to the ecu. Then you could actually tune your car to the desired air/fuel ratio for example to 12.5, as well as keeping the ecu supposedly re-learning itself to 12.5 so your changes actually stay that way. It was just a thought, does something like this sound realistic or no? Thanks!
04-08-2005, 02:32 AM
you can use the SMT-6 to do this... fyi :P
but just keep in mind that the output is NOT linear...
04-08-2005, 08:07 AM
i considered this idea too, the problem is that you will always be modifying the o2 signal..
the right thing to do is to install a guage on the sensor out put before the modified signal wave is sent back to the ecu so you can always see the " real " o2 signal ..
then send the ecu whatever signal you want via the tuning device..
also, a problem with o2 sensors is that they constantly fluctuate at anything below 80% throttle position ...
anything is possible, i guess it just takes time.
now here is the bad news... wideband o2 sensors are differential sensors, the ecu does not just read 1 value from 1 wire, it constantly sends a different input signal to balance out the ouput signal... how the hell can you tune that !! ?? LOL
narrow-band sensors would be easy to trick because they ecu does not use a " reference " input signal ...
04-08-2005, 01:34 PM
Damn seems like the smt-6 will take care of pretty much anything u need. Didn't know you could do that.
keep in mind that the output is NOT linear...
I believe some are though, from that pdf document for example: "The Linear Oxygen Sensor" even if the output signal is not linear you could write a simple polynomial to fit the curve of the signal right?