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Old 02-10-2009, 10:36 PM   #810 (permalink)
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Originally Posted by dcb View Post
can you clarify? What vehicle? What adaptations? What was broken?
97 Audi A6 V6. Using Fundamental Logic MPGuino. No hardware adaptations. Getting VSS & fuel flow signal from the ECU.

VSS is dialed in, works perfectly. When first installed, the GPH and MPG were working in reverse, i.e. step on the gas and GPH goes down/MPG goes up. The fuel flow signal is a negative pulse so I reversed the FALLING/RISING and now GPH/MPG work the way I'd expect.

However, when I am coasting, not pressing the throttle, over a few display cycles, the GPH ramps down to zero and then back up to a really large value. Something like 30 GPH. And the MPG goes the other way to a very low value. When I step on the gas again, GPH immediately drops to a normal number and MPG rises.

I've confirmed with a scope that the ECU cuts off the injectors when coasting. The signal goes completely flat line. It's when that happens that I see the large GPH number.

I asked about the code because I'm wondering if a variable might be rolling over to a negative number that appears as a very large integer.
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