[SpeedyCorky]

Well word on the streets says the the California model HX does not have lean burn. This limitation is due to the different ECU for the CA version. I have a 2000 HX, California version. BUT! According to my UltraGauge, i can get into what looks and feels like lean burn, in that i feel a power loss when it goes into lean burn, and a power gain when it exits. This entering and exiting lean burn is confirmed by the UltraGauge when the 2nd O2 sensor reads "0" (when it enters lean burn), then raises back up to .7 or .8~ once it has exited lean burn

Now, i can only stay in 'lean burn' for about a minute, usually a lot less. getting it into lean burn, you gotta throttle up to a good 90% load for a few seconds, then back off throttle down to 30%~, and it *usually* goes into what looks like lean burn (or what looks like lean burn as described above).
well, is it actually lean burn?! i have my doubts.....mostly because no matter how sissy I am with the throttle, i cant get it to stay in lean burn (obviously increasing throttle takes it outta lean burn right away); but also i'm not sure if i'm actually in lean burn, simply because of the fact that i've heard that the CA version doesnt even have lean burn! so wtf!? yes, I do notice a *instantaneous* MPG increase when it is in "lean burn".

so I guess the first thing to ask is: am I in lean burn?
if not, then whats going on? maybe the CA ECU only allows lean burn for a very short time?


next thing to ask (back to the post topic):
would swapping in a 49 state (federal) version HX ECU, enable me to properly get into lean burn (and stay there)? so basically, is the ECU the only difference between a CA and a Federal HX?

yes, my car has a 5 wire 02 sensor.

54mpg on my last tank.... but those numbers are for sissycakes - i want 60!!!!