I was curious about the grounding on the O2 sensor with my stainless headers. I'm running an AFS-74 Delco sensor.

Anyway, I checked the resistance from the sensor body to the (-) battery terminal. Measured about 3 ohms. Is this out of spec? If so, what problems could it cause?


I'm going to have to write a song about this...

"I've been workin' on the misfire, all the liv long day..."

 

3 ohms is nothing,.. depending on the quality of the meter, just the leads will read some resistance, my newest fluke reads the leads anywhere from 0.2 ~ 0.5 of an ohm depending on what the temp is.

*edit*
you got me curious, so i went out & checked mine, read around 4.5 ohms with the stock manifolds.

 

What's more often more important then absolute resistance, is voltage drop. Try reading across the *ground*, with the engine running, and see if you get *any* voltage reading across the ground.

A poor ground can lead to a multitude of problems. It's like asking if you have a sprained ankle, what kind of problems can you have?, it all just depends.

 

O2 sensors are fairly high impedence/low current, so I doubt it's easy to get voltage drop across 3-4 ohms. Could be happening a little, very little, but doubt it's causing any issues.

Edit: wait, you're talking ground side. uh... still should be no problem.