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Old 03-13-2008, 09:44 AM   #8 (permalink)
Join Date: Dec 2007
Location: South Louisiana
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FarFarfrumpumpen - '03 Volkswagen Jetta Wagon GLS Premium

Quorra - '12 Tesla Model S P85
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From TDI Club (i'm having SGII issues )

Scangauge is reading:
0C - RPM
04 - Load
05 - Engine coolant temp
0B - MAP
0F - Intake air temp

Then using the engine displacement, the "Diesel A" formula, and the correction factor, SG calculates fuel consumption.

There are no other codes being read, so (after this and other testing) I'm forced to come to the conclusion that there is no way to read any directly related fuel info (like inector pulse width, or VAG monitor group 15, zone 3) through the OBDII protocol on Diesel VWs.

There is one other possibility...I'm monitoring the ISO K/L lines only. It's possible Scangauge is using the CAN lines to gather additional data, but I doubt it. If so, there would be no need to read these OBDII values. An easy test would be to remove these lines from SG and see if it can still display FE data.

This calculation will, and does, work well - as many Scangauge owners can attest. It does not, however, take into account certain factors like EGR activity, injector timing to control emissions, and changes in fuel quantity based on fuel temp. That's partly what the correction factor is for. But I see now why there is such variability beween the highway and city driving.
Latter discovered that the CAn bus is NOT being used.
2012 Tesla Model S P85
2013 Nissan LEAF SV totaled by now deceased intoxacated driver.
2012 Nissan LEAF SV
6 speed ALH TDI Swapped in to a 2003 Jetta Wagon
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