ScanGauge II accuracy

[mattyyg]

Hi all, newbie here, hope I'm doing this right.

Just wanted to see if anyone has employed one of these in their CRZ and noticed the difference in fuel economy numbers? When I use the ScanGauge II see averages into the 50's at the end of a 50+ mile trip however the car's fuel economy gauges show considerably less. By considerably less, I mean high 40's. Even the instant mpg's are about 5-7mpg different.

Secondly, when I do it the old fashion way by calculating my fill-ups, the computer shows less by about 2mpg's on average.

This makes me think the CRZ could use some calibrating.

Thoughts?

[ITEM9]

Are you on stock diameter tires?

[gozoner]

The onboard computer is usually within 1 mpg with my hand calculation. See my fuelly.com link below - I record the computer's number in the 'notes.' Last two have been 43.9/43.9 and 43.1/43.0 - right on.

Also, maybe the Scan Gauge needs calibration? But, since the gauge should be connected, through the OBDII connector, to the same 'car data bus' as the driver meters, I'd expect the numbers to just agree.

[gordonfc]

what is a 'scanguage 2'?

[mattyyg]

@ITEM9, yes the car is all stock with the exception of a K&N filter. But that brings up another item I noticed, when I hit 61mph and above on the dash, the ScanGauge differs by an additional 2mph.

@gordonfc, it's a device hooked up to the odbII jack that gives you some insight on what's going on under the hood. ScanGauge - Trip Computer + Digitial Gauges + ScanTools

[mattyyg]

Originally Posted by ITEM9

Are you on stock diameter tires?

Yes, the only thing I've Put in us a k&n filter

[mattyyg]

Originally Posted by gordonfc

what is a 'scanguage 2'?

It's a little device you plug into the odbII port to give you some insight on what's going on under the hood. ScanGauge - Trip Computer + Digitial Gauges + ScanTools

[MachVEvan]

I have a little experience with these gauges. As far as I can tell, they are dead on accurate for temps, pressures, and sensor displays, but as far as MPG is concerned...the stock readout is what I would trust. These units have been out for a while and I doubt that they interface well with hybrids in that respect.

[gozoner]

Page 20 of the Scanguage User's Manual talks about calibration.

[mattyyg]

Originally Posted by gozoner

Page 20 of the Scanguage User's Manual talks about calibration.

Saw that, it mainly talks about calibrating for your gas tank and not about mpg stats.