Scangauge accuracy

[PaleMelanesian]

Originally Posted by MetroMPG

open source MPGuino, which measures actual fuel use through monitoring injector pulses, instead of extrapolating it from air intake (which is what the SG does). Once you get the MPGuino calibrated for your vehicle, it will be accurate regardless of technique used, open/closed loop, etc.

Originally Posted by winkosmosis

Why doesn't the Scanguage do that?

The scangauge is a plug-and-play device that reads from the OBD-II data port. Injector pulses are not reported on OBD, so it can't use that data. It is accurate as far as the data available from that source. MPGuino reads from the ECU directly, but you have to connect it to the wires under the dash.

Scangauge: plug-n-play, pretty good accuracy, reads/clears error codes, can transfer between vehicles
MPGuino: best accuracy, but harder to install and semi-permanent installation

[tomlai]

I now believe the is s glitch in the SG itself. I was using the four Gauges
1. LOD
2. TPS
3. Tank Trip LHK XGauge
4. Current Trip LHK XGauge

for a very long time ... say, about 6 months at a single stretch without adding any new Gauges, etc. The only activity would be to adjust Tank FillUp. Sometime during this period, I started to P&G more extensively, I would get exceptional Tank/Current mileage, but the tank fillup compensation would always show that I wasn't actually achieving figures any near what SG was reporting.

After posting this problem on ecomodder, I changed some of the gauges around and now have LOD, MAP, Current Trip LHK Xgauge and Current Trip Cost XGauge, and shuffled the positions of the Gauges around, suddenly the massive +173% Tank Fillup compensation is having effect!!

So at the last fill I massively decreased from +173% to +135%, and can see that there will be fruther dramatic reduction at the next fill ... I didn't want to completely reset the SG, so I am pulling back the fillup compensation tank by tank.

Now I am getting pretty BAD mileage figures and so I am sure the SG is back on track.

So, what can I attribute this change of behavior on the part of the SG? Was there some sort of SW glitch ... that didn't permanently disable the instrument, but caused it to ignore the fillup compensation value altogether??

[detectorguy]

With the SG2 Installed and working, my gas mileage has only improved. I have not been able to get what some of these big hypermilers get, but I am happy. With each fill up of gas the SG2 seems to be getting more accurate on gas used with each fill up.