while at Kennedys dyno tune today we had a good long chat with the owner , and one of the topics of discussion was 02 sensors, modern ecu’s and the use of O2 sims
from what was explained to us, its not simply a CEL / SES light that will fail you on inspecition.
alot of modern computers are designed to actualy check that a O2 is actualy reading exhaust gasses, they do this by INTENTIONALY changing the mixture and watching for confirmation of this from the 02 sensors
if one of your sensors doesnt report back properly, the computer will assume that that sensor is simply not ready to be tested , and sets a code that tells itself to go back and check again later on, and for the time being it simply ignores that sensor
this code apparently will also fail you ! this is because despite the fact that it doesnt throw a cel / ses light , its still a code saying that the o2 isnt properly working
using an o2 sim that is simply a resistor will not fool the computer … the computer is looking for that “wandering” a/f mixture
now i dont know what other options there are out there, but he mentioned that using the “casper” o2 sims … which are either 46 or 90 buck on their website … is a GREAT option , he said they work great and has never had a problem with them
http://www.casperselectronics.com/Merchant2/merchant.mvc?
here is a build it yourself type sim … designed to creat an oscillating signal for tricking the ECU
http://www.mkiv.com/techarticles/oxygen_sensor_simulator/
one of the other options that i know about is modified “spark plug anti-foulers” which is actualy a mechanical setup what still uses the stock o2 sensor
http://forums.evolutionm.net/showthread.php?t=98573