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AFM actuators have failed again on track for my Z51

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AFM actuators have failed again on track for my Z51

 
Old 05-14-2018, 11:03 PM
  #201  
Don Pablo GS
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Originally Posted by BaylorCorvette View Post
There is a member here working on it as we speak: https://www.corvetteforum.com/forums...post1593300099
What did you end up doing to fix the AFM issue?
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Old 05-15-2018, 01:30 AM
  #202  
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I got the same issue on my 2017 Z51. If there is an upgrade to the valves it certainly doesn't work on my 2017 car.

First it threw code P26C8, then P12F0 & P12FD where one is for the left bank and one for the right bank AFM valve. I could not care less for these valves since I avoid Eco mode and V4 Mode at all times! However my NPP valves are still working.


I got the error during active driving in Track Mode and Sport 2 setting so it is probably a heat issue, if not it might be that I never use Eco mode and they got stuck (my theory to save the Torque Converter).


I will have it checked in roughly a week during the first 7500 mi service.


//Motors5
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Old 06-09-2019, 02:59 PM
  #203  
COL Dave L
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I just lost my fifth - #5 - AFM actuator valve at VIR last week for my 2016 Z51 A8 with just 9,000 miles!! I also had the GM paid ceramic coating for my exhaust, and it's done nothing. Big issue for GM, I'm told, is that the problem involves EPA certification and they can't come up with a fix that will be in compliance with that certification. Several inherent continuing issues with C7's that seem to be fading from attention of GM with the huge engineering focus on C8. Disappointing.
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Old 06-09-2019, 03:26 PM
  #204  
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Dave, take a look at this for a cure https://www.corvetteforum.com/forums...hp-tuners.html
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Old 06-09-2019, 04:44 PM
  #205  
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Originally Posted by ErnieN85 View Post
Dave, take a look at this for a cure https://www.corvetteforum.com/forums...hp-tuners.html
If you don't have HP turners, you can still remove it and leave it dangling:
How-To: Eliminate AFM actuator melting issue for aggressive/track driving: link.
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Old 06-18-2019, 09:48 AM
  #206  
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My 2018 Grand Sport is back in the shop for the third set of afm valve failures. 348 miles since the last ones were replaced. It is happening at every single track day with 30 minute sessions. Three track days equaling three failures. I also saw the posts about the dealer PDI confusion over the center air dam being installed on dry sump cars. It was installed on mine by selling dealer and being researched now by servicing dealer. I tried very long cool downs to help but did not even make it through the second morning session with Chin on Memorial Day before the CEL light was on again. Now carry an OBD reader with me so I can be sure of no real engine problems. Otherwise I would be heading home early every time. Hoping to hear from dealership soon. This is an absolutely wonderful car otherwise. Very happy with the A8 on the track.
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Old 06-19-2019, 12:22 PM
  #207  
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Originally Posted by Sebring Bill View Post
My 2018 Grand Sport is back in the shop for the third set of afm valve failures. 348 miles since the last ones were replaced. It is happening at every single track day with 30 minute sessions. Three track days equaling three failures. I also saw the posts about the dealer PDI confusion over the center air dam being installed on dry sump cars. It was installed on mine by selling dealer and being researched now by servicing dealer. I tried very long cool downs to help but did not even make it through the second morning session with Chin on Memorial Day before the CEL light was on again. Now carry an OBD reader with me so I can be sure of no real engine problems. Otherwise I would be heading home early every time. Hoping to hear from dealership soon. This is an absolutely wonderful car otherwise. Very happy with the A8 on the track.
I find it just sad that GM never fixed this AFM valve actuator failure issue. I highlighted it when it happened to me every single track day several years ago with my 2014 Z51 M7. All they needed to do was upgrade the design of the actuator to resist heat which would have been very simple to do for a company the size of GM and likely they do not even make the part but farm it out to a supplier. They would not need to change the function of the part, just make it stand up to the heat. It's like they have their heads in the sand about the issue and don't care at all about their customers who track their cars with those actuators or overheating issues like I had. I long ago sold mine for that reason and bought other cars which run just fine on track, no overheating, no failures.
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Old 06-19-2019, 03:43 PM
  #208  
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Has anyone explored making some kind of high temperature, insulating gasket to sandwich between the actuators and the exhaust pipes? Something like Hondata uses for their intake manifold gaskets (Source)?

I'd be happy to try this out myself before heading to the track, but I don't have the education in this field necessary to know what a good, available material might be. I would also consider wrapping the actuators themselves if that seems like a good idea.
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Old 06-19-2019, 04:23 PM
  #209  
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I think BaylorCorvette solved his issues by putting a few washers between the exhaust pipe and actuators.
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Old 06-19-2019, 08:44 PM
  #210  
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I wonder if the ZR1 exhaust cooling fins would help.
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Old 06-21-2019, 08:58 AM
  #211  
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The ZR1 baffles on the tunnel plate will not help. I installed them on my 2015 Z51, ran the North Course at VIR and the drivers side actuator failed. I also had the pipe wrapped with header warp back to the Muffler.

bill
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Old 06-21-2019, 09:01 AM
  #212  
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I now have new afm valves and the middle air dam has been removed per the GM PDI form. Looking forward to another track day soon!
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Old 06-22-2019, 04:58 AM
  #213  
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Default removal of middle air dam?

Originally Posted by Sebring Bill View Post
I now have new afm valves and the middle air dam has been removed per the GM PDI form. Looking forward to another track day soon!
Bill. Could you please explain what this removal of the middle air dam per the GM PDI form is about? Is this a GM PDI aimed at reducing the frequency of AFM actuator melting problem?! If so, could you please provide us with the information we need to reference this particular PDI at our dealerships.
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Old 06-22-2019, 03:14 PM
  #214  
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PDI is pre-delivery inspection. The middle air dam is the plastic air deflector in the front center of the car and has nothing to do with the AFM actuator, but removing it may keep the under side of the car cooler.

Last edited by djnice; 06-22-2019 at 03:15 PM.
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Old 06-22-2019, 03:36 PM
  #215  
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I see djnice has already explained most of this. I would just add under the Tadge answered from awhile back that the afm valves are very sensitive to the air flow under the car. My hope for my GS is that removing the middle air dam will help with my track days.

From Tadge. “A few important points: The valves are very sensitive to air flow under the car. Anything that restricts that airflow could increase the chance of an issue arising. These would include any aftermarket aerodynamic or cooling aides. Also, lowering the standing height (which many folks are tempted to do to lower the center of gravity) of the vehicle below spec has a measurable negative effect”
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Old 06-22-2019, 09:32 PM
  #216  
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Thank you DJNice and Sebring Bill. That is a great idea. Please let us know how it goes for the AFM actuators at your upcoming track days. I also had the AFM actuators break on my first open lapping track day. It was 98 degrees or so at HIgh Plains Raceway near Denver, and I pushed my GS with an A8 transmission harder than I thought I would be able to for several hours. I was harder with my shifts than I needed to be (ie- lots of downshifts to second). Plus I forgot or was just plain ignorant about cool down laps! All in all everything else performed flawlessly and my fluid temps remained acceptable throughout the day with no overheating despite my aggressive driving. Because of this, and despite the AFM actuator problem, I was so pleased with the GS (and the A8) so I really hope I can figure out a solution. I believe I am seeing that people have figured out aftermarket solutions (which may void the warranty but would allow us to continue to track our C7's for years to come).

I do hope that we can all find a solution to our AFM problems. If we do, let's do everyone a solid and try to remember to tell everyone here what we did that worked for us. Best of luck.
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Old 06-22-2019, 09:37 PM
  #217  
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"If you don't have HP turners, you can still remove it and leave it dangling:"

X25. Could you possibly tell us more detail about how you let your AFM actuators "hang" while you track. That sounds like a pretty sweet solution. Maybe it is self explanatory, but do you literally just unscrew them and let them hang by their wires?!. Do you then reattach them after you are done tracking? Don't you just love the C7. If I can find a simple solution to the AFM actuator problem, I will be very happy. Thank you.

Last edited by noisymeditation; 06-22-2019 at 09:40 PM.
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Old 06-22-2019, 10:15 PM
  #218  
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Originally Posted by noisymeditation View Post
"If you don't have HP turners, you can still remove it and leave it dangling:"

X25. Could you possibly tell us more detail about how you let your AFM actuators "hang" while you track. That sounds like a pretty sweet solution. Maybe it is self explanatory, but do you literally just unscrew them and let them hang by their wires?!. Do you then reattach them after you are done tracking? Don't you just love the C7. If I can find a simple solution to the AFM actuator problem, I will be very happy. Thank you.
Here you go:
How-To: Eliminate AFM actuator melting issue for aggressive/track driving: link.

It essentially removes them permanently from exhaust stream, but there's no impact to the car's operation, except you might hear V4 mode engage more easily. I've never had any issues, despite countless track days with the car.

Last edited by X25; 06-22-2019 at 10:16 PM.
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Old 07-11-2019, 06:33 AM
  #219  
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I guess I've been lucky up to this point with tracking my 2015 Z51 but now my car has been in the shop for a week waiting on parts for the dreaded AFM actuator failure.

My 3 year bumper to bumper is up but they are replacing them under my extended warranty with just a deductible charge to me. They say it's not covered under the powertrain warranty even though the rest of the AFM system would be...

Curious to know if any of you have gotten their AFM actuators warrantied under power train?

If the dealer has this right I guess it's small price to pay. But another reason to move to a new car when my 7 year extended is up. Just when I have this car perfectly dialed in for track use and all the overheating issues solved I'll feel the need to sell.

I also had been experiencing a slow but definite coolant fluid loss with evidence of coolant finally appearing in the passenger wheel well after my last track day. This was diagnosed to be from the water pump which has now been replaced along with the thermostat.

The other issue that sudden appeared last track day was a warning about the airbag system on the dash DIC under heavy braking. Turned out to be something to do with the passenger seat airbag sensor.

Very capable track car in terms of speed, but not at all bullet proof like most Porsche cars are on track. I can't use that speed for more than a few hot laps at a time or for very many track days before shop time is required.

Although I look at it as being able to keep up to or even outperform those P cars on track for half the price.

Last edited by formula80_ca; 07-11-2019 at 06:35 AM. Reason: Spelling
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Old 07-12-2019, 08:55 PM
  #220  
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There are a few ways to handle the AFM issue, now. You can:
  1. Cut out the like AFM piece like I did, and leave it dangling in there, connected, but out of exhaust stream.
  2. Unbolt it, put a few washers, and install it back. This isolated the part enough to keep it from breaking down.
Regarding water pump: a friend of mine from work, I think it's related to your overheating issues. An unlucky friend of mine from work, who has a 2016 Z07 with A8 has gotten into limp mode more than a few times in our local track. After these, in time, he's had A/C failure, water pump failure like yours, and also the s/c pump cavitation issue. I think these are all actually related with the overheating, which puts too much stress on all these components. In other words, I think the mother of all these issues is overheating.

I don't think you will run into such issues once you install the AUX cooler, especially on an LT1. Airbag issue, well, is likely unrelated : )
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