Active Fuel Management Question
Team Owner
Joined: Aug 2007
Posts: 136,140
Likes: 2,432
From: I live my life by 2 rules. 1) Never share everything you know. 2)
St. Jude Donor '11-'12-'13, '16-'17-'18
I think he's asking the minimum speed at which AFM would kick in regardless of tranny. As in, would it kick in at 25 MPH or only highway speed?
(I don't know as I never use it)
(I don't know as I never use it)
Moderator
Joined: Feb 2006
Posts: 39,081
Likes: 17,937
From: DFW Area TX
Yeah, unfortunately, the manual gives no clue as to what the operating parameters are other than the Auto/Manual difference. Since I have a manual and it is never in ECO mode, I have no experience with it.
Burning Brakes
Joined: Apr 2014
Posts: 854
Likes: 302
It seems to vary, and it will engage in 4th or 5th as well as the top gears. M7 car. Actually, I don't get the hate over it because on the highway I get 32 mpg and there is barely any lag going in/out. Then again, I can switch it off...
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Melting Slicks
Joined: Nov 2013
Posts: 2,016
Likes: 73
From: Texas
What fouling? Do you have a source for your concern or just internet rumor?
GM ran these engines for massive amounts of time on rot gut, garbage gas w/o issues.
Most of the C7s out there have a 5 yr engine warranty. I’ll bet you won’t need it for fouling. Don
GM ran these engines for massive amounts of time on rot gut, garbage gas w/o issues.
Most of the C7s out there have a 5 yr engine warranty. I’ll bet you won’t need it for fouling. Don
Moderator
Joined: Feb 2006
Posts: 39,081
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From: DFW Area TX
Melting Slicks
Joined: Feb 2006
Posts: 2,172
Likes: 104
From: Des Moines Iowa
Yep, believe that I've seen that "fouling" referred to as 'coaking'. a possible issue for all direct injection engines. Good reason to use a top tier gasoline, and maybe a dose of Chevron Techron Plus every year as a pre-emptive attempt to minimize the coaking....
Drifting
Joined: Nov 2014
Posts: 1,782
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From: Salado TX
That won't help the issue with a direct injection engine.
Melting Slicks
Joined: Oct 2010
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From: Fair Oaks, California
2017 C7 of the Year Finalist
Thread Starter
Advanced
Joined: Sep 2010
Posts: 88
Likes: 1
From: The Villages Florida
In driving today, with the instant fuel mileage displayed
and in "D", I found that it would go into 4 cylinder mode
just about any time you let up on the gas or were coasting.
When in "M" it never went into 4 cylinder mode, not even in
8th gear at 60mph.
and in "D", I found that it would go into 4 cylinder mode
just about any time you let up on the gas or were coasting.
When in "M" it never went into 4 cylinder mode, not even in
8th gear at 60mph.
Drifting
Joined: Feb 2015
Posts: 1,478
Likes: 520
From: West Columbia Texas
To the OP.....after seeing your thread a day or so ago....I did a little testing to give you an answer. just remember I have an A8. I had the car on ECO mode and in "D".....and the AFM system would go into V4 mode ANYTIME I maintained a constant speed.....even at 15 MPH. and I gotta tall ya.....going that slow in our cars is REALLY REALLY HARD to do!!! BUT.....it will engage at any speed.
Burning Brakes
Joined: Apr 2015
Posts: 1,176
Likes: 128
From: DFW Texas
Ahhhh--excellent point! Yes this is 100% correct and there are solutions to this as well. Mine is going to be done in the near term on my next trip to Florida.... I love the AFM on my Z06 and on my 6.2 in the 2014 Truck it works outstanding. Lets me get a little bit better MPG's on the road esp.
Race Director
Joined: Sep 2013
Posts: 11,825
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From: Ft Lauderdale
Tech Contributor
It does not kick in based on speed but load. When the car can maintain the speed on 4 cyl it will do so. F you want to kill the AFM on a manual trans, never use ECO, on an auto trans, buy a range technology AFM defeat module.