I'm trying to install an O2 enhancer and was testing by the book before I fry my computer. It says in the Haynes book that if you connect positive lead to signal wire and neg to ground ignition switch in the on position, truck not running that it should read 400 to 450 millivolts, I'm getting 4.5 volts, I even got a different meter to make sure. I'm using a didgital multimeter and need to know if maybe this is a wide band O2 sensor instead of narrow? I found the signal wire near the computer harness for the upstream O2 sensor(orng with gry strp) and I pulled the O2 connector and did a continuity check to make sure it was the right wire, then I reconnected and did the test. Any ideas? The enhancer adds a very small amount of voltage to the circuit and makes the computer think it is rich so it will lean out the mixture and I have an HHO Dry cell running along with a pulse width modulator.

rhutson in NC

 

It sounds like you got a o2 heater circuit wire. These wires will have ~5v with key-on and the voltage won't drop unless the o2 sensor is connected. If you can tell me year,make,model, and engine, I can pull you up a wiring diagram.

 

Thanks 00DakR/T, It is a 98 Dakota 5.2 4X4. I traced what the Haynes book says is the signal wire OR/TN Orange with a tan stripe. I might just try all the wires one at a time and see what I get.

Thanks for the help, rhutson in NC