Quote Originally Posted by Robbomaz View Post
Speaking for OUR ECU, which is probably programmed a little differently, when you hook up a bank of sensors and watch behavior you can see where the poor fuel consumption is coming from.
At 20% TPS ign was +40 and A/F was 14.2, At 25% the ign was +12 and A/F was 12:1.......ANY kind of load saw these numbers, with the A/F dipping into the mid 11's at WOT. The system stays in closed loop a lot of the time and has knock sensing so the setup is odd to say the least.
Wow...Are you sure that's "normal" for the fleet of VX units? If so, it shows that the WOT circuit must be set to engage at 25% TPS. That's certainly possible -- as it's a "trick" for tuners to do this to make a performance tune/motor seem snappier. It also shows why the people getting the best MPG drive (and I quote) like a tennis ball is under the gas pedal.

Running in closed loop is normal. That's what all motors (should) do after open-loop warm-up. Closed loop means the O2 sensor is providing feedback to the ECM for correction of the fuel trim data.

14.2 is the correct stoic ratio for ethanol (E10). So, that part would be correct -- unless you were running 100% gasoline.