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Old 09-05-2008, 03:25 PM   #9 (permalink)
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Join Date: Aug 2008
Location: Massachusetts USA
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Ziggy - '95 Audi S6 Sedan

Manfred - '97 Audi A6 Quattro Sedan
90 day: 20.61 mpg (US)

Clarabell - '03 Audi A4 Quattro Avant

Sherman - '98 Audi A6 Quattro Avant

Cab - '96 Audi Cabriolet
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The only expanation of the fuel consumption signal that I've found is this:

"The fuel consumption signal is a data message which is conditioned by the engine control unit. The sum total of the high levels during a defined period of time corresponds to the injected fuel quantity."

So, it sounds like I just have to count the pulses that occur within, let's say, 100 mS. The problem is, what volume of fuel does that number relate to? I may have to just estimate a ballpark volume and then adjust with every fillup.
After logging more fuel consumption signals, I'm coming to the conclusion that the 97 A6 signal is one pulse for each injector firing and the pulse width is the length of time that the injector is open. So, the signal includes the injection time for all 6 injectors not just one. Summing the pulse width time is the total injector open time.

Now I need to monitor the pulse width at 75 mph where I get about 22 mpg. Then I can calculate the approximate injection time per gallon. Soon.
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