O2 not sweeping very quickly...

I was monitering the O2 sweep on the scan tool on my xj and it seemed to be very slow. So I put a new O2 in and it didn't seem to sweep any better.

any ideas?


cone filter
had LT1 injectors, but I put the stockers back in and no sweeping changes


MPG are about 15

What is the rate of change you are seeing?
From what I have read, the rate of change should be at minimum 1 once per second at operating temperatrure...I think a new one would probably sweep aprox. 90 times in 1 minute....
Do you know for sure that your scan tool is sensitive enough to track and display the voltage change and frequency? Is it displaying a full swing from approx, .9v to .1v ?

I was watching it on the graph mode. It is definatly not as fast of a change rate as my GM cars.

I will moniter it some more on Monday

It could be a combination of timing delays in the engine computer data bus talking to the scanner and time used by the scanner to calculate and draw the graph. Try an analoq ohm meter directly to the O2 sensor if you want the real signal timing.

Might help to mention the scanner model, year, and jeep year and engine.

Master Tech 3000 scanner

1996 4.0 XJ