[SentraSE-R]

Originally Posted by dcb

I think it isn't really well quantified as to the effects, hardly enough information here to make an absolute decision, yet people are making decisions ?!? In lieu of the fact there are quantifiable efficiency gains, and that the cat is still 600+ degrees even with cooling dfco air going through it?!?

We know p&g can save lots of fuel

We don't have no clue how it affects total emissions, if at all.

Needs serious testing to have a serious discussion.

You're ignoring the elephant in the room. My engine is fine, emitting normal HC levels after normal cat-lit operation. It failed to run the cat drive cycle and set the appropriate readiness flag because P&G doesn't light the cat.

When the smog test was done the first time, after 800 miles of P&G operation, HC levels were 62, 15.5X higher than average, and just 2 below failing, and the smog test is done with the cat lit. If a lit cat is 90% efficient, then my P&G (no, every EOC P&G) that never lights the cat is dumping 155X more HCs than the average car.

100 miles of cat-lit operation brought my car's HC level down to 39, 10X the average, on the second smog test.

900 more miles of cat-lit operation brought my xB's HC levels down to average

If that's not a cause and effect situation, and you really have doubts about it, you need to propose another more likely cause and effect for us to consider and test, if necessary.

When I get home, I'll take my xB on a P&G EOC drive to Costco, or on my 10 mile test loop. I have no doubt I'll fail to light the cat at all in local low speed P&G. It takes 3 blocks of driving to raise the cat temps to 550F (light the cat). Each low-speed pulse moves me 1-2 blocks, followed by several blocks of coasting