Active Fuel Managment Strategies?

[JAY4SPEED]

What would be the best strategy for keeping active fuel management (displacement on demand) less sensitive at highway speeds @ 65 - 70 mph on a stock truck? In particular I'm using OS 12617631 and Cal 12617630 on a stock '08 Avalanche w/ 3.73 gear and stock height tires. Customer wants his AFM (4cyl mode) to stay in longer at highway speeds. I've lowered B0921 to B0936 and raised B0941 to B0960 to open the RPM operating window so that AFM doesn't kick out due to RPM. I get confused on table B0950 AFM Enable Min Vacuum and B0951 AFM Disable Min Vacuum. On B0950, do I understand it correctly that the area under the plot line on this table AFM will allow AFM to be enabled making this plot line the "ceiling" of AFM and if we cross the plot line to the area above, AFM will be disabled? On B0951 the area above the plot line will allow AFM to be enabled and if it value drops to the area below the plot line, AFM will be disabled, making this the "floor" of AFM?

I've tried to raise B0950 and lower B0951. I've attempted to log kpa vs RPM but have inconclusive results to see what is kicking me out of AFM. It seems at speeds of around 70 mph the slightest throttle position movement will kick it out of AFM no matter how big the window may be. Has anyone had success with enabling AFM for longer at highway speeds? Are there more tables than we have access to that affect AFM kicking out?

Thanks in advance for any help.:)

Jay

[vortecfcar]

Try bumping the max TPS to 9% or so.

Nick

[JAY4SPEED]

Try bumping the max TPS to 9% or so.

Nick

B0960? I currently have it set at 50% and still no joy.:bangin:

[GAMEOVER]

I have it set at 12% and I focused on the Vacuum between rpms 1700 & 2300 in 4th gear. I lowered the Vacuum till it would enter 4 cyl.mode at 70-75mph. It works great on the freeway but in town it really sucks because it would always be in 4cyl mode. So I use that setting for highway cruising only and disable the 4cyl.mode in town:) I actually get better MPG with the AFM disabled in town....weird!!!

[GAMEOVER]

EDIT
I went on a 400 mile trip and my AFM didn't want to activate after I re-flashed my ECM last weekend!!! I re-flashed it, to activate AFM, about 5 different times and still would not come back on:( MPG went from 22 highway to about 16-17 highway

Anyone else have this problem????????

[GAMEOVER]

With EFI Live 7.5.4 I could Disable and Enable the AFM whenever I wanted and with the new EFI Live 7.5.5 I can't.......Anyone have any Ideas???:)

[JAY4SPEED]

Also, the AFM pid {GM.AFM} doesn't seem to work so that you know when AFM is active when logging. In fact I had logging hang issues that I believe may be tied to selecting that pid.

[GAMEOVER]

I also tried a Full Flash...with no luck!

[GAMEOVER]

I'm going to have to switch out the E38 ECM with a stock one I guess....:)

[GAMEOVER]

Why can't I re-activate the AFM?

[860]

did you ever get this resolved?

[tblu92]

If you have disabled the COT (cat overtemp ) system in your tune the AFM will not activate at all--

[GAMEOVER]

did you ever get this resolved?

Yes, it was the COT....I re-enabled it and it worked fine...