stevem5215;1740910y6 said:
But there is a TSB like you mention for known faulty solonoid operation on them. . . Also, the average gas mileage was around 15mpg which is what it's been for ears. . . . But, in this case it turned out that the Bank 1 solenoid was intermittent. . . . Yep, that solenoid has been intermittent for years GM knew they failed hence the TSB. . . . . Steve BTW.. my gas mileage is now an average of 19mpg! . . . That's the best it's ever been on this car.. . . All due to a incorrectly advancing timing advancing system.
Very interesting, Steve and thanks for sharing. The wife's 2011 3.0 XWD with 52,000 miles has run relatively well, never set a code or had a CEL, but always got that inexplicably low 15 MPG in town, 19 on the highway. Suddenly, the in-town improved to 18 and the highway to 22.8. Is it possible the solenoid just unstuck itself or wore into more clearance?
FWIW, in another thread, I described installing the new Michelin GreenX low rolling resistance tires and how the fuel economy improved 15% on a 1500 mile round trip. At the time, I mentioned I couldn't believe the tires were responsible for that much improvement. Now, I'm thinking the solenoid you describe is in the mix as well; the in-town mileage had improved before the tires.
Thinking back on this latest trip, it now has more low end power. Before, on cruise, it would have to drop out of converter lockup and/or downshift one or two gears to pull certain hills that now it could pull in sixth locked up. It was a more relaxed feel.
Bottom line, the first 50,000 miles, it must have been stuck with the one or more of the cams in high-RPM mode. I'll have to do some more research on exactly what and how those solenoids function.
jack vines