RPM read on laptop is unsteady

[Power Wagon]

Even when the motor's running very, very steady, and not real slow, the rpm readout, the analog display, etc, all are unstable. They change by up to 200 rpm constantly. Even when you are watching the advance config display, the "active" cell will hop back and forth between cells while the engine rpm isn't changing.

I don't have a tachometer on this motor and wanted to run it a specific rpm and discovered I simply can't tell what rpm the motor is running at closer than about 150 rpm or so. You just "guess" as the display constantly changes.

Any ideas on this? Do I have a problem, or is it just a software issue or???

BTW, this is an inline six...

Thanks

[brentp]

You might want to check for proper shielding on the PIP / SAW lines going between the EDIS and Megajolt. Ensure you're using a shielded cable and that shield is grounded at one point, ideally the same ground point you're using for everything (megajolt/ EDIS/ shield - "star" grounding scheme)

Also look if the wires are being routed near the HV plug wires.

Finally, ensure you're running resistor plugs- non resistor plugs will generate a lot of RF electrical noise, which can interfere with electronics.