[arpad_m]

For some fun and satisfying my curiosity, I've been trying to figure out when exactly AFM kicks in and out on my own, but if someone has a link to definitive docs, I'd appreciate it.

Basically, what I see is it goes from V6 to V4 mode when driving on a level road or a slight decline and being easy on the throttle, but not letting up completely, somewhere between 10% and 25% throttle if I go by feel. Then V6 mode is reactivated whenever I tap the brake, let off the accelerator or go beyond 25-30% throttle. Might also be linked to RPM. Cruise control I haven't tried yet, too bad I've only thought of it just now.

What I don't fully understand is why it doesn't engage more often. There were long stretches yesterday where I was definitely within the envelope of these parameters I could observe, RPM fairly low between 1500 and 2500, yet the LGX remained in V6 mode. Interestingly, instant fuel economy levels were still pretty high at 40-50 mpg despite no cylinder deactivation occurring for minutes.

So I'm not trying to argue for or against AFM or establish some uber fuel economy regimen, as it's not much fun to stay at 45-50 mph and hardly touch the pedals, just want find out how exactly to exercise it best, because it could be useful on longer highway trips. Or perhaps when wifey gets behind the wheel, should that ever happen.

[cellsafemode]

I dont have any references specifically for the lgx. But it's been documented for V8->V4, there is a 10 min time limit and then the engine must return to full cylnders (8) for 1 minute before entering V4 mode again. No reason to think the same doesn't hold true for V6->V4.

the factors i think matter are engine load and requested torque. If it's above a certain limit it switches to V6. It also switches to V6 to preempt the need for full power like when you start downshifting, taking sharp turns at speed etc.

Basically if it's an activity that would show the decreased power of V4 mode, the ECM avoids it by switching to V6 before you have something to complain about.

[arpad_m]

Originally Posted by cellsafemode

I dont have any references specifically for the lgx. But it's been documented for V8->V4, there is a 10 min time limit and then the engine must return to full cylnders (8) for 1 minute before entering V4 mode again. No reason to think the same doesn't hold true for V6->V4.

Thanks, I haven't considered possible time limits for V4 mode or the necessity of running in full cylinder mode for some time afterwards. Makes sense and explains why I couldn't "make V4 happen" at certain points despite low torque demand on mostly straight highway sections.

Originally Posted by cellsafemode

Basically if it's an activity that would show the decreased power of V4 mode, the ECM avoids it by switching to V6 before you have something to complain about.

I'm all for preemptive measures and indeed this sounds like a good strategy. Do you have a reference to the time limit for V4 mode or other non-LGX specific AFM details by any chance?