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General question. Has anyone had any engine problems or heard of engine problems with the system that drops 4 cylinders on lightly loaded engines? I've read several articles on YouTube and this forum from folks reporting mechanical issues as a result of the engine cutting out 4 cylinders to improve gas mileage. I'm asking because I recently bought a 2014 Z51 3LT with 13751 miles and was wondering if I need to be concerned about this. Thanks...
There is a lot of hate on the V4 mode due to sound, vibration and simple preference. It’s a fuel economy measure that adds an extra level of complexity that can be the source of maintenance issues with dirty oil being the prime suspect.
From: In a parallel universe. Currently own 2014 Stingray Coupe.
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However, the 2014 has an A6 tranny, not an A8. For the A6 (as well as an A8), a workaround is to purchase a Range Technologies AFM Eliminator - it will keep your car in V8 mode all the time. Have one on my 2014 and consider it a purchase well worth the money.
I have a 14 with A6. I bought a Range unit last may, before we took our multi state trip out west. The Range worked as promised. I had the car for two years before getting the Range, and never experienced any problems, but decided for a long road trip, I was ready to get a Range.
The nice thing about these cars is that they get excellent mileage. We have a 19 base Stingray, a 15 Mustang GT w/ Performance Package, and a 21 Honda Pilot. The STingray is our mileage champ. I have gotten 31mpg on a long interstate trip and regularly get 25 overall average. I autocross mine and one of the venues is 2 hours away. 15 min house to interstate and 10 minutes interstate to venue. Last time I checked I got 27.8 overall including the autocross. Mine is an M7 and I tried the 4cyl mode once just to see how it worked. It works I suppose but, other than that test, I have never used it.
I used to think that AFM was no big deal and that it wouldn't hurt anything but when I had a rattle in my 2018 that necessitated the replacement of my driveshaft and flywheel, I quickly became an AFM hater. I know I don't have absolute proof, but a lot of people have told me that my driveshaft issue was most likely caused by the vibrations from going in and out of 4 cylinder mode. I used to use the paddles only 10-20% of the time in my car, so it often went into 4 cylinder mode. Yes, it gave me slightly better mileage (about 1-2 MPG better on the highway) but knowing what I know now, I will be using the paddles all the time now, and eventually I will be buying a Range AFM disabler. Thankfully I haven't had any engine or transmission issues, and hopefully now I won't!
FWIW, even without AFM, I have found these cars get incredible gas mileage (over 35MPG on the highway) so it's really not necessary to use 4 cylinder mode.
I agree that AFM is a "person of interest" when it comes to drive train breakdowns. I tried the Range unit and found that it worked just fine but there were some peripheral issues that I didn't like so I removed it. I went to paddle shifting and after a few weeks of training it became second nature to me. I prefer paddle shifting.
I forgot to add, adding paddle extensions shortened the learning curve considerably.
Last edited by AZRenegade; Dec 6, 2021 at 10:55 AM.
Well as soon as I can track down this AFM disabler I will install it on my stingray. I love the car, and you're right I do get great gas mileage, at least for such a stout engine. But I don't want to constantly think about the possible damage being done when it's running of 4 cylinders.
Well as soon as I can track down this AFM disabler I will install it on my stingray. I love the car, and you're right I do get great gas mileage, at least for such a stout engine. But I don't want to constantly think about the possible damage being done when it's running of 4 cylinders.
I found this one on Amazon to be the lowest price out there for $119, been following this thread and was thinking of buying one myself for the 2017 I just purchased.
I do "paddle-shift" my car roughly 20% of the time. From now on I'll only paddle shift. When I had my C6 I used the paddles about 90% of the time so I know I can get used to it. Think I'll go that route instead of the AFM eliminator.
On my last trip to Florida, I had my M7 C7 in Tour mode and averaged 31 MPG on the interstate. After reading about AFM issues, I don't bother using the Eco mode.
Last edited by Casper001; Dec 6, 2021 at 03:54 PM.
I purcjhased mine from Amazon. Once received, I called Range and gave them the serial number etc to make sure it was their most updated version...it was.
General question. Has anyone had any engine problems or heard of engine problems with the system that drops 4 cylinders on lightly loaded engines? I've read several articles on YouTube and this forum from folks reporting mechanical issues as a result of the engine cutting out 4 cylinders to improve gas mileage. I'm asking because I recently bought a 2014 Z51 3LT with 13751 miles and was wondering if I need to be concerned about this. Thanks...
GM trucks had DoD starting in 2007 and there were valve train issues with a fair percentage of the trucks up until 2011 or 12. After that, the valve train issues dropped off considerably. Newer trucks and cars with DoD (or AFM if you want to call it that) don't seem to have the valve train issues of the earlier vehicles.
With automatic transmission cars, the lock-up torque converter is declutched when the engine mode changes. That seems to have caused some issues with the A8 transmission in both the cars and trucks.
What is interesting is the M7 cars have no issues with switching back and forth from V8 to V4 and back to V8 mode. If you don't have some way to tell (like looking at the IP display or having the exhaust set in track mode so you can hear the exhaust get quieter and then louder) the mode change has occurred you really can't hear or feel the mode change. It is basically seamless.
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However, the 2014 has an A6 tranny, not an A8. For the A6 (as well as an A8), a workaround is to purchase a Range Technologies AFM Eliminator - it will keep your car in V8 mode all the time. Have one on my 2014 and consider it a purchase well worth the money.
