The "let's brainstorm how to make a piggyback work" thread - Toyota Yaris Forums

eTiMaGo · 03-25-2009, 11:50 AM

sounds like that could work too, but what really worries me is the self-test check the ECU does (very rich for a second, then very lean, and see how the sensor reacts. If it does not react, CEL)

though looking back at the manual's explanation, The HO2
sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V). That sounds like reducing the voltage of the sensor's output should be enough to trick the ECU into thinking the system is lean, thus enriching the mixture? Problem is, no way to tune that...

03-25-2009, 11:50 AM	#11
eTiMaGo vroom vroom View User's Garage Drives: lil red 5-door Join Date: Sep 2006 Location: Bangkok, Thailand Posts: 7,744	sounds like that could work too, but what really worries me is the self-test check the ECU does (very rich for a second, then very lean, and see how the sensor reacts. If it does not react, CEL) though looking back at the manual's explanation, The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V). That sounds like reducing the voltage of the sensor's output should be enough to trick the ECU into thinking the system is lean, thus enriching the mixture? Problem is, no way to tune that... __________________ The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson Bye bye 1NZ...