O2ptimizer FAQ: 

Q:  Do I need the 3X or 4X O2ptomizer? 

The 3X was designed for vehicles with the standard oxygen sensor(s).  If you have a vehicle that uses AFR sensors or wide band 02 sensors, you will get better results with the 4X.  The other issue is that of floating grounds.  Older vehicles route the one wire from the temp sensors (CTS & IAT) to ground.  The 3X works with them.  Many of the newer vehicles have both of the wires returning to the ECU; this is the floating ground system.  The 3X only has one signal wire that splices into the CTS and IAT sensors.  If you have a floating ground, the 3X probably won’t work up to peak efficiency.  All vehicles ’99 and older are 3X compatible, while most (not all) vehicles newer than ’04 will probably do better with the 4X.  Some research on your part will determine the correct answer. 

Q:  Is there a way to check the O2ptomizers to see if they are working? 

To start with, all O2ptomizers are military-spec bench tested before they are shipped from the manufacturer.  We have only had one that was faulty.  There have been instances where the installer has shorted out wires that have fried the electronics, but even that is rare.  Sometimes a 3X O2ptomizer is installed on a vehicle with floating grounds, or with an AFR sensor.  The results may be less than ideal.  The only way to tell if it is working is to hook up a scanner that reads the data stream and watch your readings.  Go to the O2 sensors and watch the voltages.  You should see the readings jumping around.  Since the O2ptomizer modifies the input, a faulty controller will not output any signal.  There are other possible issues, but usually problems stem from the improper install or tuning, not a faulty O2ptomizer. 

Q:  Do we install the O2ptomizers under the dash or in the engine compartment? 

The most important issue is that it be mounted someplace relatively cool and absolutely dry.  Typically, installers like to install it near the factory ECU.  This makes the installation easier.  If you are installing a 3X that requires turning a screw for adjustment, mounting it in the passenger compartment will allow you to tune while you drive. 

Q:  If we install 2 O2ptomizers what do we do with the blue and yellow wires on the second one? 

You only need to hook up the blue and yellow wires on the first unit if you have 2 coolant sensors, in which case you wood hook up the second set of blue wires to the second coolant sensor.  I have not yet seen a vehicle with more than one IAT sensor.

Q:  Do we hook the O2ptomizer to the upstream O2 sensor (ahead of the catalytic converter) or the downstream O2 sensor (after the catalytic converter)? 

You will only ever need to address the upstream sensor.  The downstream sensor merely tells the ECU that the catalytic converter is working.  Of course on V-configured engines, you have 2 upstream sensors.  This is why the O2ptomizers have 2 separate O2 sensor circuits.  You never need to worry about the downstream sensor. 

Q:  We are wondering if on a carbureted vehicle that has no O2 sensor or IAT sensor how do we hook up the O2ptomizer? 

You don’t!  Just hook up the rest of the kit without the O2ptomizer.  You will get maximum benefit if you take the time to change the jets and adjust ignition timing after the install.  Since modern computer controlled engines don’t have the adjustability of the older vehicles, we created the O2ptomizer.  For older vehicles, you tune them the same way they have been tuned for decades. 

Q::  Wiring instructions for the O2ptomizer