All about the C7 Corvette AFM and why its a problem

Having an engine stall issue since installing the Range module. It did everything as advertised but do not like engine stall. The stall is rare and occurs when approaching a stop. I was made aware of this issue from a service advisor at my local Chevy dealer. He also experienced the stall issue. Decided to remove the module.

Excellent

So many issues with this generation. Sigh….friggin’ GM. :(

This engine keeps me from buying a Corvette, who the hell needs that aggravation I don’t understand why GM continues to make this shit if they must make it why don’t they just put a switch in the vehicle where the owner can switch it on and off when he wants to it should be left up to the person that owns the car not GM PS stop making a goddamn motor with that

I am a mechanic for a local Buick and GMC dealership. They make us replace the lifters on V8 GMC trucks, right of the transport truck.

I have had the pleasure of speaking with you on the phone. You are very professional and passionate about Corvettes. Every product I have purchased from you, has worked out very well. I also enjoy watching your videos, they are very informative.

Why GM has continued with this for so long is shocking.

They say the range unit is not compatible on the C8’s. The only two ways you can stay out of V4 mode is to shift in manual mode, which isn’t too bad because it automatically down shifts you just have to do all the up shifts. The second way is to select track mode everytime you start it up. Of course ride quality is harsh. I have a 2023 C8.

I disabled the afm as soon as I purchased my C7. Don't want to risk the headaches.

I would like to buy a Corvette, and this video along with others have rained on My Parade, apparently a major problem is also with the lifters collapsing and requiring replacement, even on a 2024 Corvette, such a nice car and engine and they've actually ruined it with this active fuel management.

Lyle, does the afm have anything to do with the transmission shudder that affects some C 7's
I had the shudder in my 2015 and the fix was to do a triple transmission flush

It's funny how mistakes always get repeated. GM did not learn from the '80s in this case. And why would they, right?

Makes you think twice before buying a C7

my lifter came apart at 61,000 miles on a 2017 grandsport, and destroyed the cam and put metal into the engine, $10,500.00 later I had the AFM system pulled out and had all the metal shavings remove

I bought the Range unit for my 2016, and plugged it into the OBD of my 2019 GS before it left the dealers lot. No problems to date, and the engine is quite happy.

Hello Lyle. No one seem to be able to give a straight answer on the problem of the AFM system. I drive a 2011 Ram 1500 with the system no problem to date. ( December 8, 2023.) Also have C 7 2019 no issues with system. If system causes issues why is GM and others still using system? Is the problems with system is the loss of power to engine?

I have a 19 stick, but plan to get rid of the system all together. Some interesting information. What if you have a dry sump, with a variable pressure oil pump? Lot’s to undo.

Thanks for sharing. I’m in the market for c7 what year you recommend for the best

You said long term a couple of times. In regards, to Not keeping the Range device inferring that; there’s an end use of the Range Device. If that’s correct, what would be a reason to stop using the Range Device other then adding a Supercharger, Cam swap or new tune because what you did requires a new tune to the ECM. Cheers, a fellow Sarasota long time resident😎

thanks Lyle. New sub.

I've had my C7Z51 for almost a year. I learned of & put the range device on the OBD2 port as you described before I refueled the second time. Had a Chevy service writer recommend it. As you mentioned, GM put this silly system on all their V8s ... the writer had a shop full of Suburbans, Tahoes and pickups with lifter problems. Shifting back to V8 is where the system runs afoul.

I wasn't aware of the high volume oil pump. wonderful. smh. I've been pretty particular about checking oil levels after an AX/Drag/Track event. So far, the LT engine has not burned any extra.

This is my daily. have put 20K on it in just under 12 months. fun car. though the wheels are not very strong. Have them getting repaired right now. IDK what to do about that long term. anyhow, I digress. Glad to have one. glad to have guys like you pushing great info, too.

I assume it would hurt the car.and who wants a automatic sports car?oh that's right all chevy corvettes owners after 2019

I bought a C6 to avoid this C7 problem.

Great straight forward explanation of how the System works ( or doesn’t ). Good job as always explaining in layman’s terms how these complicated experiments in gas mileage stretching are further complicating our cars ! Luckily I drive a Manual . 👍

Do you know if this AFM system is on the LT4 crate motors

I have been looking for a c7 to buy, but everyone I test drive has shutters down low speed and I think it is a scam and a serious problem and I refuse to buy at the prices 50 grand plus

I traded my low mileage C7 for a 2023 C8. I had AFM problems, mostly after I changed to a Borla Exhaust.

Lyle, awesome videos all the time love your Chanel. I just bought a 2015 c7 stingray. it has 17000 miles on it.
after I bought this car I see a lot of these videos about the AFM and the transmission cause I have the 8 speed automatic transmission needing a trip flush. it make me wonder if I made a mistake .I love this car but had no idea about this issues. so worried now.

Lyle, I love all your videos! I did find something out, however, about the AFM disabler you refer to in this edition. I wrote to them and asked them how I actually know that the V4 is not engaging, other than just not getting the indication on the instrument panel. His reply was kinda shocking. Now I was asking about my 2014 Silverado, not my 2003 C5, to which it does not apply. But I have a 6.2L with an A6 transmission, and all the disabler does is put it in M5 mode. So you completely lose the final overdrive gearing, and you are paying $230 for something you can do for free! I am sure it is the same for the C7.....most likely just goes to M7, or the C6! Honestly, to me it is dishonest that they dont tell you this. It doesnt really disable the AFM, just puts you in M5, or M7, which ever is the case. Here is the reply:

The device would put the vehicle in M5 mode to prevent the AFM from kicking on. It is most noticeable if you have an aftermarket exhaust, the disabler would prevent the “droning” sound coming from the exhaust when the AFM normally activates.



The disablers do reset the emissions readiness modules. We would recommend disconnecting the disabler and driving the vehicle for 50-100 total miles for the readiness system to show a ready status.

So basically, c6 gs is better than a c7 gs. I am looking for vette and it has to be an auto. My left knee is JUNK, so the standard is not an option. By the way I think your videos are kewl!!!

The AFM was more a problem in earlier models mostly in trucks. These later models it is much less an issue and the odds are likely you will never have an issue.

These systems really do little for mpg or emissions. GM gets credits from the government for installing and it helps reduce the gas’s guzzler penalty.

Most of these latest AFM engines were redesigned and issues are few compared to the early LS engines in the trucks.

I you are building an engine for sure remove it. But don’t panic you have to do this or fear of sure failure.

The Ranger tool eights well.

I work in the performance aftermarket snd we sell the parts to fix these and that is where we see what works snd what fails.

Great video. I am trying to decide if I want to buy a 2019 C7. Not really looking for a problem. Your video was very informative. Thank you for your time.

Just came across the video and a new subscriber. Thanks for the additional info. Had a '14 Z51 A6 and didn't worry about this too much. Now have a '17 GS A8 20K miles (purchased Dec. '22) and knew of the potential AFM issues... Bought a Range Finder a few weeks ago but have not plugged in yet as I started having the infamous transmission shudder issue. Driving back from my first big road trip (1500 miles) and experienced the shudder...have an appt in a few weeks for the triple flush recommendation and will definitely plug in my Range thereafter!!! Have read that it should be unplugged before any dealer work so the engine is back to its oem function when they get their hands on it....will be searching to see if you have a A8 transmission shudder issue vid... Missed you at Carlisle!

Thank you so much for you time and information I love you podcast you are so great with your information on everything you do I can't thank you enough

What's the ballpark cost of doing a delete on a C7 Stingray Vette?

My G8 GT had this. Camshaft and lifters replaced under warranty at around 25K miles. Yuck. Only issue I ever had with the car.

I had a delete kit system when katech rebuilt my motor the motor didn’t last a year before it spun a bearing an katech took no responsibility for it ,my advice leave your motor alone at least GM warranty is honored

That's really useful mate!
I'll add that it is recommanded that you don't leave the AFM disabler in the ODB port because it drains the battery!

I have a C7 Z06/Z07 with the 8 speed automatic and I'm using the AFM disabler since I hit 4,000 km, I now have 5,500 km so far so good. I just need to plug it in and out when I enter/exit the car.
It is my week-end car as I have a company car to go to work so removing the AFM disabler from the port is mandatory for me.
I will now check to install the AFM kit through my mechanics shop thanks to this video as I don't want to have any issue with my car in the future
And this I will need to replace the cam shaft, why not going for an aggressive one then and get a small tune out of it?!

Thanks so much for this valuable piece of infotmation! Really appreciate it.
Greetings from Belgium.

Cheers!

Drove my c7 cross country on a move, used 4cyl mode on freeways (most of the trip). At destination, the engine blew a lifter. Luckily, GM warrantied the engine, which would've been a $17,000 fix elsewise. If I want to save fuel, I'll use 7th gear

BS. I would have to PASS on a C7 completely.!!!

Just did a 7hrs drive to Biloxi Ms, from Georgia plans were to use Eco mode, after learning about cylinders dropping out to save gas, i kept car in Sport mode i do occasionally get the shudder but keep my foot on the accelerator at those certain speed to eliminate the shudder, i will be buying the Range device, and by the way coming back from Biloxi had to make several more than usual gas stops, one from whooping Azz in Ala, and Ms, i rather pay for gas than a new Engine 😂 2017 Z06

I did some research on how often a ZO6 goes into V4 and according the articles I've read and talking with certified Corvette mechanics they all claim because of the supercharger it will hardly ever go into V4,

I had a 2019 C7 and never knew this! So glad I had a manual but I never heard about this... dam Whew..... Thx for this...

I’ve never liked the rear end of the C7 & now C8. This cylinder deactivation & direct injection were just more reason I’ll never own one., Keeping my 2013 Grand Sport forever…

My C7 is a manual. So what your saying is stay outta Eco-mode and that'll help save the life of the engine?
BC I've only used it a handful of times. The long one was a 2hr road trip i took with a good friend of mine following me. He loves Honda Accords. I did it just to aggravate him that i got better economy than him in car with potentially double the HP. 😜

Great video. Not a problem for me anymore I just traded my Z for redeye.
Redeye has factory dod delete! Yay!

The problem with the Range device is that it resets the emission monitors. That requires getting them re-established in order to perform annual emissions checks. That usually requires several hundred miles of driving with yge Range device removed. Annoying.

I have had my C7 for 9 years and have no problems with this item