[turbocruiser]

Originally Posted by landtank

I don't think it does and here is why. During my MAF testing I data logged the O2 sensors as well as other ones. If the fuel was cut anytime during the operation there would have been a noticeable spike in the readings from high O2 levels. I don't remember seeing that and I was scrutinizing the logs pretty closely.

x3

No spikes in O2 levels, but AFR does immediately go to 16 (or leaner), and load immediately goes to the 12% level which is what idle is or sometimes lower if you are actually coasting down a steep grade with OD off and letting the engine brake against the vehicle. I am almost positive that more or less the amount of fuel injected is at idle levels or something slightly less than idle levels (because idle is always at an AFR of 14.7 or so - richer than the 16 we see without any pedal at all and coasting). I am also almost positive that the fuel pump never stops seeing voltage and that the spark plugs never stop seeing spark - I'd think that at the least the FP would not receive voltage in a non-fueled mode and maybe also that the spark plugs would stop seeing spark. I believe (although might be wrong with this) that all the selectable cylinder engines out there like the Northstar cutoff both fuel and spark. HTH.