djnice

I am still waiting for an explanation of why the N&V will be an issue on A8, but not M7.

dar02081961

My guess is the flexplate and torque converter harmonics operate in a slightly different frequency range than the clutch and pressure plate.
thus allowing the manual to skate by without it.

AKKutz

Well now, I'm getting scared! I have a track event this Sunday. Now, I guess I have to candy *** my car around and hope that I don't fry my AFM valves. I bought this car to take it to the track. I sold my track bikes in order to do so. I put all my focus in prepping and tracking my C7 and now I have to worry about some insignificant valve in my exhaust train that can ruin my day!! WTF!


I specifically bought the Z51 pack as it was touted as a track pack vehicle!!!!! Anyone want to buy a C7????

X25

Just do 2-3 cool-down laps until you solve the problem for good : ) Hopefully, this will keep them from overheating.

IN54NITY

LOL. You and Tadge think you're the only ones to do cool down laps? (Pulling your leg, but not Tadge's.) I do cool down laps: Still have the problem. In order to save the CEL for something important short shifting at 5k ~may~ work. Oh yea... And the cool down laps.

IN54NITY

I hear ya. I have a shiny set of coilovers sitting on my living room floor for my "track whip". I'm thinking I may have to burn out these AFM Actuators 3 more times and lemon this thing, and put the c/o's on a 2017 GS or Z51.

X25

Sorry, that was not my intention, and I don't think cool-down is even sufficient, judged by descartesfool's experience, where he melted them in just 30 minutes. I removed them before even going to my first track day; I don't want anything to fail. If I end up having a legitimate reason for warranty work, and I get denied, I will not bother convincing anyone, and will just sue; I don't have time to deal with illogical service managers, etc.

AFM is the only big issue with this car, and there's a fix. Just get it done and get it over with. I did an open session track day at 95+ degrees with oil temps never hitting 270, so with the OEM cooling aids; this platform is very stout. My Camaro would hit 290s easily in the same conditions, even with an aftermarket oil cooler. Just add better brakes, better cooling (all OEM parts) and delete AFM, and you have a great track car. I'm actually pretty happy with the platform.

FYI, I don't see how GM can deny powertrain warranty if you delete AFM. After all, 2017 cars or all Z06s don't even come with it, which has no ill-effect on longevity.

AKKutz

Well, I may just be in the same boat. I attended my first track outing on Sunday. I drove moderately, found out afterward that I was in wet track mode. Drove 3 hours back from track with no issues. Today on my way to work, I get a CEL. I don't have a scanner with me, so I won't know until I get back home tonight. But, I'm going to bet it is the AFM valves. The killer is, it wasn't that hot and I didn't spend that much time on the track!

IN54NITY

Sorry to hear. I had codes: P26C8, P12F0, & P12FD. Similar situation as you (and described by DescartesFool and possibly others in other thread(s)): The CEL didn't come on when on track, but after the car cooled a bit. In my case, after my hot laps (2 hour session for a charity ride), I did 2 cool down laps (+5 minutes at low power while maintaining high air flow) and even drove a bit more in the paddock. Started the car to drive home, and CEL came on, when the ECU does a self-diagnostic check.

AKKutz

Don't know yet. I drove home day of event, no light. Car sat all day Monday, washed it Monday night and I get the CEL driving to work today. Again, I'll know more when I get home tonight and scan for the codes.

daleong

Any news on the codes you pulled? Hope they wern't the P26C8 or others related to the valves.

AKKutz

Yep, and it had nothing to do with the actuator. P2099, secondary o2.

daleong

Ah somewhat good news at least.

FYI - I had a P0500 vehicle speed sensor DTC pop up 2 months ago right after I washed the car... I cleared the code and kept an eye on it, but it hasn't come back yet so far.

Harris

I'm pretty sure this isn't "cased closed" from GM's perspective. While it may be frustrating to those that are affected, I'd say patience is a good virtue to have for the time being.


I think most of us have, or are, giving up on GM addressing various issues on earlier cars. Example would be the long awaited A8 "cooling kit".The attitude seems to be: buy a new one or live with what you have

kevincol

I lapped for this afternoon at Pacific Raceways. It was in the low 80's. I would go for about 20-30 minute runs and come off and drive about close to two miles before resting or going back on the track.

No error codes and exhaust sounds fine, so I obviously didn't melt them!

daleong

Great news Kevin. What did the vehicle temps look like from the PDR data? (assuming you PDR'ed the laps)

X25

You guys should keep in mind that for some, it happened only after 5-6 track days, not immediately. Obviously, your mileage may vary, perhaps it might not even happen to you : )

kevincol

daleong

Thanks for posting... the trans temps seem to be the most concerning and closest to the max.

kevincol

The straight-a-way is much shorter than it used to be, but I would typically hit 136MPH and be >100MPH on three different sections of the track. So, I think I was pushing the transmission..

I haven't driven that track in 15 yrs. with my 1998 C5 and 2001 Z06 on R Comps. I know I wasn't hitting the speeds I was hitting with this Z51 back then with those cars.

The C7 is such a treat to track -- just amazing.

There was another Z51 on the track, but for whatever reason he wasn't going that fast so I kept lapping him. I ate a bunch of Porsche's, BMW's and Mustangs....