I've tried graphing LTFTs and O2 sensor voltages along with RPM and engine temp on my icarsoft i930, and all the data has big positive and negative spikes every 5 or 10 seconds and the scale of the graph expands to cover the max and min value so the lower values between spikes are impossible to read accurately. Has anyone else had this problem? The screen is small to begin with and the (I assume bogus) spikes make the data pretty much unuseable.

I tried to video it but the video was out of focus. I can try again or try a still shot if it would be helpful to see what it is doing. I just wonder if I got a bad unit or if something else is going on here.

 

I tried my i930 in OBDII diagnosis mode to graph the O2 sensor voltages on my 98 Land Rover Discovery 1 and the time period of the graph makes it unreadable; it is just a series of vertical lines that make a solid background with no discernable oscilations at all. It was plugged directly into the OBDII connector with no splitter, and the Disco was warmed up and at idle.

One photo is bank 1 O2 sensor voltages and engine rpm and the other is bank 2 O2 sensor voltages only.

Is there any way to adjust the i930 sampling rate so it shows something useful? Or might this be a problem with the 98 OBDII setup and perhaps the reason that the i930 only reads OEM Land Rover codes on Discovery 2s and up? I do know that the 98 reports MAF values way below the range that my UltraGage expects so it thinks it is getting 2000 MPG unless I load in a huge calibration factor.