Forgot how bad V-4 mode is

Chazm · November 5, 2016

My last truck was a 5.3 (pre 2014) and my current one is the 4.3. I could usually predict when they both would switch to V4 mode and both trucks would behave almost identically. I am not doubting your observation but you would think that all engine sizes should switch to V4 mode under similar load requirements.

I drive 80% at speeds over 70mph and that's when I mostly notice the difference. The v8 would go to v4 mode more often at high speeds IMO

Sent from my iPhone using Tapatalk

Camaro45th · November 5, 2016

What I don't understand is why doesn't (my truck at least) the car switch to v4 mode when your coasting and you haven't touched the gas in a few seconds. And more importantly, when you sitting at a light, would the v4 running at a stop be more efficient than the v6 or v8 running? Just feels that they could have made the efficiency better by making it go into v4 at more practical times. Also, and Efficiency button when it always put it into v4 mode might be another option. I feel that my truck if I'm on the highway and have the cruise set and I'm going up a small incline it will switch back to v6. Im sure that the v4 could handle it, maybe RPMs go up slightly. Or just incorporate a button where you can keep the afm off when you wanted.

SouthernSilveradoGuy85 · November 5, 2016

What I don't understand is why doesn't (my truck at least) the car switch to v4 mode when your coasting and you haven't touched the gas in a few seconds. And more importantly, when you sitting at a light, would the v4 running at a stop be more efficient than the v6 or v8 running? Just feels that they could have made the efficiency better by making it go into v4 at more practical times. Also, and Efficiency button when it always put it into v4 mode might be another option. I feel that my truck if I'm on the highway and have the cruise set and I'm going up a small incline it will switch back to v6. Im sure that the v4 could handle it, maybe RPMs go up slightly. Or just incorporate a button where you can keep the afm off when you wanted.

I would think the reason it's not in V4 while at a stop is so you instantly have the V6 or V8 power instead of basically waiting for it to kick into V6 or V8. I know GM and other companies have that think where the engine actually cuts off at a stop and I don't like how it feels when you take off. It's like a bad clunking sound and feel and it's also a little bit of a hesitation. Plus at idle you're not really going to save that much if the AFM activated so it's not a bit deal. I so wish they had a button where you can just turn it off like you say. You can turn off TC, Stabilitrak and Grade Braking so why not AFM. I personally would leave it off around town unless I'm going on the interstate or highway then I would turn it on.

Camaro45th · November 5, 2016

I would think the reason it's not in V4 while at a stop is so you instantly have the V6 or V8 power instead of basically waiting for it to kick into V6 or V8. I know GM and other companies have that think where the engine actually cuts off at a stop and I don't like how it feels when you take off. It's like a bad clunking sound and feel and it's also a little bit of a hesitation. Plus at idle you're not really going to save that much if the AFM activated so it's not a bit deal. I so wish they had a button where you can just turn it off like you say. You can turn off TC, Stabilitrak and Grade Braking so why not AFM. I

personally would leave it off around town unless I'm going on the interstate or highway then I would turn it on.

I really am not a fan of the start stop tech. It's kind of annoying. I feel that it has to be bad for the starter and there is such a delay in hitting the gas to move when it stops. I really don't think the v4 to v6 or v8 from a stop would be that significant since the engine is already running. The other 2 or 4 cylinders would be running in motion by the time you went to press the gas.

Side note, do the cylinders have a set that are the ones that always shut down, or does it alternate? I thought alternating would be good to always give 2 or 4 different cylinders a break as apposed to always the same 2 or 4

SouthernSilveradoGuy85 · November 5, 2016

I really am not a fan of the start stop tech. It's kind of annoying. I feel that it has to be bad for the starter and there is such a delay in hitting the gas to move when it stops. I really don't think the v4 to v6 or v8 from a stop would be that significant since the engine is already running. The other 2 or 4 cylinders would be running in motion by the time you went to press the gas.

Side note, do the cylinders have a set that are the ones that always shut down, or does it alternate? I thought alternating would be good to always give 2 or 4 different cylinders a break as apposed to always the same 2 or 4

It's the same cylinders and they criss cross so it's like a V4 formation. I can't remember which cylinders, but I know I looked it up when I first got the truck. Also I know it's not much of a feel between V4 and V6/V8 while driving, but I bet you'd feel it if it did it at a stop. Doing it while in motion is different than at a stop.

Ok looked it up, I believe it's cylinder 1,4,6 and 7 are deactivated. So the 2 on the outside on the driver side and the 2 inside on the passenger side.

redwngr · November 6, 2016

. I personally would leave it off around town unless I'm going on the interstate or highway then I would turn it on.

Have you tried just putting it in M5 when around town?

SouthernSilveradoGuy85 · November 6, 2016

Have you tried just putting it in M5 when around town?

No, but it doesn't really bother me. Not enough to put it in M and select up 4 times every time I go to drive. I'd rather turn it completely off or leave it on and in M5 it would still come on, just not as often.

winn0040 · November 6, 2016

No, but it doesn't really bother me. Not enough to put it in M and select up 4 times every time I go to drive. I'd rather turn it completely off or leave it on and in M5 it would still come on, just not as often.

AFM will NOT activate in M5.

djxn40 · November 6, 2016

uh huh.... I can get upper 20's at low speeds too, I am guessing you are going to say that is at 75 mph or something?

Back to the OP and this thread. V4 isn't to blame, people just want to find something to blame it on that they do not like because they are all stuck on V8 all the time for sound and POWER and V4 mode is for pansies. You can't even tell when it switches with the stock exhaust.

V4 is great, I watch it jump 3-4 mpg's every time it switches in to that mode. How anybody can say it does nothing is beyond me and a basic understand on how mpg's work. Oh but the reliability they say. Yes some early adapters had some issues (almost 15 years ago) but outside the rogue problem now those have been mostly handled. None of ours that have had it have had a problem or oil consumption issues going to or above 100k and one of my best friends has over 200k on his Tahoe with no issues. Just people trying to incorrectly find something to blame for some minor transmission tunning issues. News flash, the more gears you have the more chances for it to get confused.

Funny to watch read all these types of threads and comments.

Tyler

Yep. On the turnpike. 35 miles on the turnpike and that 27.4 was from 25 miles of that turnpike. And yes at 75. I guess your not tuned. Or you would probably know that already

Sent from my SM-N920P using Tapatalk

SouthernSilveradoGuy85 · November 6, 2016

AFM will NOT activate in M5.

Maybe I'm thinking the wrong way, but wouldn't that mean AFM only activates in 6th gear and I'm pretty sure it's activated in other gears. I've had it go into V4 going only 20 MPH so I highly doubt it was in 6th.

winn0040 · November 6, 2016

Maybe I'm thinking the wrong way, but wouldn't that mean AFM only activates in 6th gear and I'm pretty sure it's activated in other gears. I've had it go into V4 going only 20 MPH so I highly doubt it was in 6th.

It will activate in lower gears...just not while in M5. I had Black Bear tune mine out until 55mph as I wasn't a fan of it kicking in around 30mph.

truckguy82 · November 6, 2016

Each truck has different afm activation. Some are smoother than others.

UplandPa · November 7, 2016

If it weren't for the posts on here, honestly I would probably forget I even had AFM!

redwngr · November 7, 2016

Maybe I'm thinking the wrong way, but wouldn't that mean AFM only activates in 6th gear and I'm pretty sure it's activated in other gears. I've had it go into V4 going only 20 MPH so I highly doubt it was in 6th.

You are correct that AFM will activate in 5th and lower but only if the transmission is in normal full automatic mode mode.

When the transmission is in M mode, AFM will not work unless it is in M6 (or M8 on and 8 speed).

Also, when any M gear is selected, the transmission will still use all the lower gears, same as in full auto.

M4, for example, means that it can use 1, 2, 3, and 4, but not 5th or 6th.

The result is if M5 is selected it will use gears 1 thru 5 as necessary, but it will not go into V4 and it will not use 6th gear.

SouthernSilveradoGuy85 · November 7, 2016

You are correct that AFM will activate in 5th and lower but only if the transmission is in normal full automatic mode mode.

When the transmission is in M mode, AFM will not work unless it is in M6 (or M8 on and 8 speed).

Also, when any M gear is selected, the transmission will still use all the lower gears, same as in full auto.

M4, for example, means that it can use 1, 2, 3, and 4, but not 5th or 6th.

The result is if M5 is selected it will use gears 1 thru 5 as necessary, but it will not go into V4 and it will not use 6th gear.

I know what it does in M5 that it will go through the gears up to 5th. Same as with the older style with 3,2,1 or 2,1 on the dash beside D. I just didn't think that AFM wouldn't work just because you put it in manual. I was being sarcastic in the reply since I know it will go into V4 in a lower gear which is why I said I've had it go into V4 going 20 MPH. Maybe I'll try it, but I'm not too worried since I don't mind V4 coming on in town. I would just turn it off in town if it was a simple button to turn it off like TC. I'm not lazy in any way, but I don't think I want to put it in manual and hit the button to 5 every single time I drive just to turn off AFM when it's not a huge bother. I guess it's more of the fact that I don't have much patients so I just want to start it and go. It's a little funny, some things I don't mind using time while other things I don't. Like the passenger windows not being auto up. I don't care so I don't complain about the driver window being the only one that is auto up. I thought about being able to install a simple switch to a power wire for AFM to turn it off and on, but I don't think it would be that easy like wiring used to be on older vehicles since these new trucks have so much wiring and that just about everything seems to be intertwined with each other. If it was done I'm sure the CEL would come on and that would be way more annoying than V4 coming on in town (which really isn't that annoying to me).