Scan Gauge 2 How it works

[Snax]

I don't believe that is true anymore. The fact is, manufacturers have determined that the old narrow band oxygen sensors which make keeping a perfect stoiciometric ratio an easy target are inadequate for optimal power and efficiency. The use of wideband sensors has opened up the ability to tune more accurately to both ends of performance and efficiency - allowing them to carefully control ratios far leaner than the standby 14.7:1.

I don't believe that all modern cars have a lean burn mode, but there are certainly many more now that do.

[Snax]

Answering the original question, I'd bet that SG actually uses injector pulse width as the primary means of metering fuel. When you first plug it in, it assumes an average rate of injector size for a given engine displacement and calculates fuel used based on the length of the injector on-time. The user calibration that you can do afterward is simply a way to correct for the assumed values of consumption, as it's a fairly linear relationship that does not change significantly with variations in atmospheric conditions.

[Bill in Houston]

Originally Posted by Snax

I don't believe that all modern cars have a lean burn mode, but there are certainly many more now that do.

Thanks guys. Hijack over.

[GasSavers_Ryland]

does it do anything to moniter manifold vaccum, so it can figure out what the fuel presure regulator is doing? or does it just figure an average fuel presure?

[Mentalic]

Originally Posted by Snax

Answering the original question, I'd bet that SG actually uses injector pulse width as the primary means of metering fuel. When you first plug it in, it assumes an average rate of injector size for a given engine displacement and calculates fuel used based on the length of the injector on-time. The user calibration that you can do afterward is simply a way to correct for the assumed values of consumption, as it's a fairly linear relationship that does not change significantly with variations in atmospheric conditions.

I agree, the scangauge must use injector pulse's as the primary method of accounting for fuel burn. Otherwise while maintaining the same RPM on cruse you should always see the same fuel burn/mpg rate yet it does not. I flip on the A/C I see a few mpg drop, a truck changes into my lane and my MPG jumps up.

[usedgeo]

I don't know how it works but I know that on a Saturn the IAT has a huge effect on the reported mileage. I asked Ron about this and never got a reply. You can deceive your self about 20% if you want .

I have been considering installing an IAT resistor just to get more consistent results.