O2 Sensor Output

[MANWHOR3]

Hey Guys

I ran consult on my car and graphed the output of the 02 sensor under different conditions. My car has stock ecu, so it is untuned.

On idle, it was basically sitting around 0.8v. It would oscillate between 0.75 and 0.85.

Holding a constant speed of 40km/h in 3rd on flat ground had it oscillating around about 0.7(0.65-0.75).

Does this sound about right?

[paulr33]

yep

[Busky2k]

No. It should occillate between 0.0V - 0.2V and 0.7 - 0.8V.

0.6V is not 'low enough'.

[T04GTR]

high voltage = rich

low = lean

in a nut shell

[RB SANDY]

I have a drift ignite series air/fuel gauge and the needle does not stay still, when you are crusing at a constant speed and when you accelerate hard in goes all the way to ritch and you de accelerate it goes all the way to lean.

I have a spare o2 sensor if I need to change it, or do I need a wide band o2 sensor.

[Busky2k]

If its cycling or occilating between rich and lean on cruise, then its working good.

[MANWHOR3]

hmmmm.... i'll look into it again tomorrow, but i'm pretty sure that it was oscillating around 0.8

I guess that sensor is worn then.

[Busky2k]

Yeah. An easy way to tell is to rev the engine to 5000rpm in neutral. The O2 sensor should go rich when you flatten the foot ie >0.7V, then down to 0.0V when you back off the accelerator. Then it should be back to normal on idle again.

Sorry in my first reply I mean that it should occillate betwen rich and lean. The upper (rich) and lower values (lean) are ~0.0V-0.2V and the rich range should be ~0.7V-0.8V

[MANWHOR3]

oh, mine does this. I guess it's normal then.

[paulr33]

an AF Guage off the stock 02 sensor is pointless and wont ever give you anything meaningful. it will always bounce all over the place. dont bother with it