Hello, curious how the Gen 5b engine works during Decel, I'm calling it a Gen5b since this is the Dynamic Fuel Management version, Gen5 being the original Active Fuel Management.

The Gen5 Active acted like a normal v8 with fuel cut.. MAP would show maximum vacuum during decel fuel cut. The Active Fuel version is showing steadily increasing MAP reading as decel goes on, eventually reaching atmostpheric pressure of 95kpa.

My question is, is this a real reading, and how goes this work? I get that if you cram more air in the cylinders without igniting fuel it will increase the engine brake effect since your compressing more air, but I don't see TPS increasing to allow more air in, so is it keeping the valves closed to create more decel? I do notice the decel is much stronger than the old Active version. Is there a valve allowing air in? Very curious.

Thanks

2020 10-1 MAP Decel Maxed Out.PNG