What exactly do you mean by poor? What are those 'ground' readings?

The O2 ground that the ECU monitor is looking at is the single brown
wire that branches from the distributor hall bundle. It needs a good
clean connection to the engine metal.

Understanding grounds is not something that most people come to very
easily. While we tend to imagine a perfect vehicle ground in reality
there isn't one when multiple currents are flowing through various
ground interconnects. The ECU monitor is going to see a voltage on that
ground. That voltage will typically fluctuate when you change the engine
speed.

I'm not saying you don't have a ground problem with the O2 circuit,
those are common. I just trying to say that even in a well running van
the ground readings won't always be what you think of as ideal and they
can still be fine. What voltages are you seeing?

Mark

Karl Wolz wrote:
> Installed an ECU monitor from Van Cafe the other day.  It is indicating a poor O2 sensor ground.  Does the sensor ground through its mount into the exhaust, or along with the heating element ground wire?  If through the exhaust, how can I improve the connection?
>
> Thanks,
>
> Karl Wolz
> Sent from my electronic umbilicus
>