[SentraSE-R]

Trying to answer older questions.

Mech, in answer to the bigger trip/maintain clean emissions issue, I have to maintain clean emissions. Longer trips 2-3X/year clean the cat, but that's putting a band-aid on a gaping wound. The gaping wound is the 75X higher than average hydrocarbon emissions when the cat's not lit. What's needed to maintain the emissions reduction found after my 900 mile SoCal trip? Keeping the cat lit.

Will I be able to come close to my previous fuel economy without EOC? No. I was getting 176% of EPA. I can expect 135-140% of EPA keeping the engine on. That's a drop from my 49.4 mpg combined average to an expected 39 mpg combined average. Considering the xB's 2008 EPA estimates are 26/30/28 city/hwy/combined, 39 mpg still looks good.

Since I started keeping the engine on, I've driven 1505 miles, and am averaging 46.3 mpg. However, ony 215 of those miles are city miles. So, if I can use the xB as a long trip car, its FE will barely suffer.

On this trip, I'm only using the kill switch on long (>1 mile) downhills, and approaching/at long stoplights. I figure restarting a hot engine barely emits pollutants, v. perpetually keeping the engine cool w/P&G.

I have two cat temp functions, Bank 1 sensor 1, and bank 1 sensor 2. When I looked at them uncritically, they looked to read the same, within 5 degrees of each other. Now I'll set them up side-by-side, to compare them while the cat is cooling/heating, and under DFCO