[SentraSE-R]

Red liner,

Unfortunately, I can confirm your observations with my 2002 Nissan Sentra SE-R. If I shut the engine off on a long downhill coast, it took a full four minutes in open loop for the ECU to decide to return to closed loop again, Even when it went into DFCO, Nissan programmed DFCO to occur only when the engine was >2500 rpm. In effect, only when traveling faster than 65 mph in top gear. For comparison, my Scion xB enters DFCO when rpms are >1500 - 35 mph in top gear, and the Scion stays in closed loop after it's been shut off and turned back on again.

On the good side, I actually kept and maintained a higher lifetime hypermiling % above EPA combined fuel economy estimates with my Nissan (170%) than I've managed with my Scion (167%), and I put about 20,000 miles on each. I suspect that running in open loop isn't as awful for fuel economy as it seems to be in theory. I managed 60 mpg EOC P&G 20 mile test drives with the relatively thirsty 170 hp 2.5 liter engine running in open loop.