AFM turned off by my dealer????

[GB EB]

I asked my service adviser and she said "Can you do that?"

[mlee]

Originally Posted by 2011 2SS/RS

I asked my service adviser and she said "Can you do that?"

LOL...sometimes they are clueless.

It's just a setting in the tune that you can turn on and off. However it constitutes a "tune" which technically voids your warranty. Very easy to do yourself if you have one of the handhelds like SCT or Diablo.

[suplex]

I wonder if the same type of thing could allow 2 cylinders to shut down from a V6 and make it run as a 4-cylinder as well?

I'm assuming this is only an SS feature and not an LS or LT feature?

[mlee]

Originally Posted by suplex

I wonder if the same type of thing could allow 2 cylinders to shut down from a V6 and make it run as a 4-cylinder as well?

I'm assuming this is only an SS feature and not an LS or LT feature?

No... it's an L99 thing only (SS Auto). Cam has a phaser to adjust timing and lifters are different since they cut on and off, among a few other things..

[Speedfreak]

General Motors Active Fuel Management engine control system has the ability, under certain light load driving conditions, to provide maximum fuel economy by deactivating 4 of the engines 8 cylinders.


The engine will normally operate on 8 cylinders in V8 mode during starting, idling, and medium or heavy throttle conditions. When commanded ON, the engine control module (ECM) will direct the active fuel management system and deactivate cylinders 1 and 7 on the left bank and cylinders 4 and 6 on the right bank, forcing V4 mode.


To provide maximum fuel economy under light load driving conditions, the engine control module (ECM) will command the cylinder deactivation system ON to deactivate engine cylinders 1, 7, 6, and 4, switching to a V4 mode. The engine will operate on 8 cylinders, or V8 mode, during engine starting, engine idling, and medium to heavy throttle applications.


When cylinder deactivation is commanded, the ECM will determine what cylinder is firing and begin deactivation on the next closest deactivated cylinder in firing order sequence. For example, if cylinder number 1 is on its combustion event when cylinder deactivation is commanded ON, the next cylinder in the firing order sequence that can be deactivated is cylinder number 7. If cylinder number 5 is on its combustion event when cylinder deactivation is commanded ON, then the next cylinder in the firing order sequence that can be deactivated is cylinder number 4.


Cylinder deactivation is accomplished by not allowing the intake and exhaust valves to open on the selected cylinders by using special valve lifters. The deactivation lifters contain spring loaded locking pins that connect the internal pin housing of the lifter to the outer housing. The pin housing contains the lifter plunger and pushrod seat which interfaces with the pushrod. The outer housing contacts the camshaft lobe through a roller. During V8 mode, when all cylinders are active, the locking pins are pushed outward by spring force, locking the pin housing and outer housing together causing the lifter to function as a normal lifter. When cylinder deactivation is commanded ON, the locking pins are pushed inward with engine oil pressure directed from the valve lifter oil manifold (VLOM) assembly solenoids. When the lifter pin housing is unlocked from the outer housing, the pin housing will remain stationary, while the outer housing will move with the profile of the camshaft lobe, which results in the valve remaining closed. One VLOM solenoid controls both the intake and exhaust valves for each deactivating cylinder. There are 2 distinct oil passages going to each cylinder deactivation lifter bore, one for the hydraulic lash-adjusting feature of the lifter, and one for controlling the locking pins used for cylinder deactivation.


Although both intake and exhaust valve lifters are controlled by the same solenoid in the VLOM, the intake and exhaust valves do not become deactivated at the same time. Cylinder deactivation is timed so that the cylinder is on an intake event. During an intake event, the intake cam lobe is pushing the valve lifter upwards to open the intake valve against the force of the valve spring. The force exerted by the valve spring is acting on the side of the lifter locking pins, preventing them from moving until the intake valve has closed. When the intake valve lifter reaches the base circle of the camshaft lobe, the valve spring force is reduced, allowing the locking pins to move, deactivating the intake valve. However, when cylinder deactivation is commanded ON, the exhaust valve for the deactivated cylinder is in the closed position, allowing the locking pins on the valve lifter to move immediately, and deactivate the exhaust valve.


By deactivating the exhaust valve first, this allows the capture of a burnt air/fuel charge, or exhaust gas charge, in the combustion chamber. The capture of exhaust gases in the combustion chamber will contribute to a reduction in oil consumption, noise and vibration levels, and exhaust emissions when operating in V4 mode cylinder deactivation mode.
During the transition from V8 to V4 mode, the fuel injectors will be turned OFF on the deactivated cylinders. To help prevent spark plug fouling, the ignition system secondary voltage or spark is still present across the spark plug electrodes on the deactivated cylinders. If all enabling conditions are met and maintained for cylinder deactivation operation, the ECM calibrations will limit cylinder deactivation to a cycle time of 10 minutes in V4 mode, then return to V8 mode for 1 minute.


Switching between V8 and V4 modes is accomplished in less than 250 milliseconds, making the transitions seamless and transparent to the vehicle operator. The 250 milliseconds includes the time for the ECM to sequence the transitions, the response time for the VLOM solenoids to energize, and the time for the valve lifters to deactivate, all within 2 revolutions of the engine crankshaft.

[cmore]

"
Switching between V8 and V4 modes is accomplished in less than 250 milliseconds, making the transitions seamless and transparent to the vehicle operator. The 250 milliseconds includes the time for the ECM to sequence the transitions, the response time for the VLOM solenoids to energize, and the time for the valve lifters to deactivate, all within 2 revolutions of the engine crankshaft."

This statement is WRONG!!!!

[Phail]

Originally Posted by mlee

Quoted for when you never come back...

Always active and a situation where some guy tricks the system into not kicking on AFM are two completely different things here.

[Switchback700]

Originally Posted by Phail

Always active and a situation where some guy tricks the system into not kicking on AFM are two completely different things here.

Not sure if I tricking it not to come on, I think the intention was to have it inactive when in manual, sport mode..... I will find out and report back when I hear from GM.

[mlee]

Originally Posted by Phail

Always active and a situation where some guy tricks the system into not kicking on AFM are two completely different things here.

You are coming off like a real ass calling the dude a liar when he's telling you whats happening with his specific car.

Sorry if I come off that way to you. I've actually been pretty reserved with someone calling me an ass and saying I'm going to eat crow...Really??... you'd have to read the wacky crap he's been posting to understand where I'm coming from. He's just now starting to figure out, like you already know, he's just tricking the system not to activate. Simple variations in RPM can do that no matter what mode you are in.

Originally Posted by Switchback700

Not sure if I tricking it not to come on, I think the intention was to have it inactive when in manual, sport mode..... I will find out and report back when I hear from GM.

I thought you were sure...

Yes you were tricking it by manually keeping RPMs outside the AFM parameters (probably losing gas mileage too). AFM will activate in ANY Mode if the rpms are within the limits. Unlike what you have been telling everyone in multiple threads... Hopefully GM or the new thread you created today will answer this for you.

I will pass this along... AFM can be turned all off or all on as you already know.
It can also be turned on or off gear by gear 1 through 6 in Drive and gear by gear 1 through 6 in Manual. Previously I've had mine turned on in D for 5th and 6th gear only and off everywhere else.

[Switchback700]

Originally Posted by mlee

Sorry if I come off that way to you. I've actually been pretty reserved with someone calling me an ass and saying I'm going to eat crow...Really??... you'd have to read the wacky crap he's been posting to understand where I'm coming from. He's just now starting to figure out, like you already know, he's just tricking the system not to activate. Simple variations in RPM can do that no matter what mode you are in.


I thought you were sure...

Yes you were tricking it by manually keeping RPMs outside the AFM parameters (probably losing gas mileage too). AFM will activate in ANY Mode if the rpms are within the limits. Unlike what you have been telling everyone in multiple threads... Hopefully GM or the new thread you created today will answer this for you.

I will pass this along... AFM can be turned all off or all on as you already know.
It can also be turned on or off gear by gear 1 through 6 in Drive and gear by gear 1 through 6 in Manual. Previously I've had mine turned on in D for 5th and 6th gear only and off everywhere else.

The exact same speed and RPM on the highway, AFM was on when in "D" and "S" but as soon as I would tap shift and put it in 6th gear AFM would stay off for a 3-4 hour trip. Please explain how this is changing the RPM's??? It would also stay off in the city at RPM levels that would usually activate it.

[Switchback700]

Originally Posted by mlee

Sorry if I come off that way to you. I've actually been pretty reserved with someone calling me an ass and saying I'm going to eat crow...Really??... you'd have to read the wacky crap he's been posting to understand where I'm coming from. He's just now starting to figure out, like you already know, he's just tricking the system not to activate. Simple variations in RPM can do that no matter what mode you are in.


I thought you were sure...

Yes you were tricking it by manually keeping RPMs outside the AFM parameters (probably losing gas mileage too). AFM will activate in ANY Mode if the rpms are within the limits. Unlike what you have been telling everyone in multiple threads... Hopefully GM or the new thread you created today will answer this for you.

I will pass this along... AFM can be turned all off or all on as you already know.
It can also be turned on or off gear by gear 1 through 6 in Drive and gear by gear 1 through 6 in Manual. Previously I've had mine turned on in D for 5th and 6th gear only and off everywhere else.

He calls it "wacky crap" because he disagrees........ and you wonder why I have haven't been so nice...... he's been arrogant and confrontational as soon as I voiced a different opinion than his.

[mlee]

Originally Posted by Switchback700

He calls it "wacky crap" because he disagrees........ and you wonder why I have haven't been so nice...... he's been arrogant and confrontational as soon as I voiced a different opinion than his.

Below is what you said to me in another thread about drone so don't act like you are clueless as to why I corrected your statement here.

Originally Posted by Switchback700

sounds like maybe you didn't have enough 4 cyl time behind the wheel, but you are misleading people saying AFM doesn't cause drone...... don't mean to argue, but comments like yours are not giving newbies good information.

.

Originally Posted by Switchback700

The exact same speed and RPM on the highway, AFM was on when in "D" and "S" but as soon as I would tap shift and put it in 6th gear AFM would stay off for a 3-4 hour trip. Please explain how this is changing the RPM's??? It would also stay off in the city at RPM levels that would usually activate it.

I do think I understand your issue on the highway and someone else noted it in another thread and you agreed. (the combination of exhaust drone and AFM noise) You were experiencing some heavy duty drone and the combination of that and AFM was making your dash shake and your head spin. AFM on the highway is not really that loud (not in the sense of HEAVY exhaust drone). AFM in the parking lot or going slow is way more noticeable. Your highway experience with switching to paddles also helped keep the RPMs out of the exhaust note drone. I know you said exact same RPMs and all but it still allowed adjustment.

Hope this helps... This is a really good example of how mis-information gets spread around a forum. One person (not you) says something as fact and the next thing you know there are 5 or 6 experts out there spreading it. It's not intentional... just happens...

[Switchback700]

Originally Posted by mlee

Below is what you said to me in another thread about drone so don't act like you are clueless as to why I corrected your statement here.





.
I do think I understand your issue on the highway and someone else noted it in another thread and you agreed. (the combination of exhaust drone and AFM noise) You were experiencing some heavy duty drone and the combination of that and AFM was making your dash shake and your head spin. AFM on the highway is not really that loud (not in the sense of HEAVY exhaust drone). AFM in the parking lot or going slow is way more noticeable. Your highway experience with switching to paddles also helped keep the RPMs out of the exhaust note drone. I know you said exact same RPMs and all but it still allowed adjustment.

Hope this helps... This is a really good example of how mis-information gets spread around a forum. One person (not you) says something as fact and the next thing you know there are 5 or 6 experts out there spreading it. It's not intentional... just happens...

I'm really not here to argue, but you are wrong in almost all aspects of your comment.......


"AFM on the highway is not really that loud (not in the sense of HEAVY exhaust drone). "

"the combination of exhaust drone and AFM noise"

AFM on the highway at 73 mph would be 4 cyls running, the drone was terrible, paddle shift to 5th then back to 6th would keep me in 8 cyls and the drone was gone. Why you keep talking about AFM as some other noise makes no sense. AFM noise IS the engine and exhaust sound running on 4 cyls and when the 4 cyls exhaust note hit the "drone" zone it was bad. AFM is not some mechanism under the hood making noise.

"Your highway experience with switching to paddles also helped keep the RPMs out of the exhaust note drone. I know you said exact same RPMs and all but it still allowed adjustment."

The RPM's are exactly the same at 73mph whether AFM is on or not, this downshifting method would turn off AFM, there was no mistaking it for being off!!!.... what is "still allowed adjustment".... makes no sense.... why are you insistant on calling my experience false?

"This is a really good example of how mis-information gets spread around a forum"

I know you don't like hearing it but your last statement is full of mis-information....... you need to realize that because you didn't have the exact same setup and it didn't happen to you does not mean that it cannot happen......

[Switchback700]

http://www.camaro5.com/forums/showth...=1#post3480560

Why don't you read "SGOS252382" response and go call him a liar also........