I've been having some trouble with one of my downstream O2 sensor sims on my Mustang and was hoping somebody here may be a little better at electronics than myself.
An automotive O2 sensor generates a low level voltage based on the diffence between atmospheric oxygen and oxygen levels in the exhaust gas inside the pipe. This difference is constantly in flux and the ECM compensates (in other words, the fuel mixture is constantly going from slightly richer to slightly leaner- like a sine wave I suppose). Now, an O2 sim works on the downstream O2's which output in the same fashion but are simply there as an indicator of catalyst effeciency and with an offroad mid pipe there is no catalyst, so the sims are suposed to "fool" the ECM into thinking the cats are there and working (THIS IS ONLY ON OFF ROAD AND RACE VEHICLES!!). The schematic is below.
Now, say the voltage should be reading between .3-.6 volts kinda floating at the extremes (eg: .34, .55, .32, .62 and so on). What mine is doing is not reading some of the time (0 volts), reading normal sometimes (not much) and then flat lining at a steady 1.275vdc. For you electronics guys, can you see a reason why that circuit would do that? If not, then the answer is simply either the wiring to the ECM hass issues or the sensor itself is outputting a funky voltage.
An automotive O2 sensor generates a low level voltage based on the diffence between atmospheric oxygen and oxygen levels in the exhaust gas inside the pipe. This difference is constantly in flux and the ECM compensates (in other words, the fuel mixture is constantly going from slightly richer to slightly leaner- like a sine wave I suppose). Now, an O2 sim works on the downstream O2's which output in the same fashion but are simply there as an indicator of catalyst effeciency and with an offroad mid pipe there is no catalyst, so the sims are suposed to "fool" the ECM into thinking the cats are there and working (THIS IS ONLY ON OFF ROAD AND RACE VEHICLES!!). The schematic is below.
Now, say the voltage should be reading between .3-.6 volts kinda floating at the extremes (eg: .34, .55, .32, .62 and so on). What mine is doing is not reading some of the time (0 volts), reading normal sometimes (not much) and then flat lining at a steady 1.275vdc. For you electronics guys, can you see a reason why that circuit would do that? If not, then the answer is simply either the wiring to the ECM hass issues or the sensor itself is outputting a funky voltage.
