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[ANSWERED] Why can you not just disable the AFM?

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[ANSWERED] Why can you not just disable the AFM?

 
Old 06-18-2017, 03:44 PM
  #41  
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Originally Posted by Supercharged111 View Post
I've got AFM in the wife's Envoy and can't feel it enter/leave AFM. That old SUV still has a 4L60E. Did they deal with it differently back then or am I on the hook for a torque converter at some point? Either way the trans itself is a matter of when and not if.

What's odd about the alternator pulley failures is that they've been doing the same thing with AC compressors for years without many, if any, issues. Hell the alternator on my 98 GMC pickup is controlled by the PCM. It doesn't have a pulley to engage/disengage but it does have control over commanded amperage which I assume is for economy. Laughable as it gets 13mpg empty and single digits loaded.
I'm guessing it's just heavier with a smaller engine. Mass damper- you don't feel it.
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Old 06-18-2017, 05:23 PM
  #42  
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Originally Posted by djnice View Post
Yes, it does stay in sport and tour. I was sort of joking since we can't turn off V4 it is as if it were always in eco.
I was just fooling around with hptuners on mine and came across where you can enable or disable "DOD". I just saw it , didn't try it. I have a 17 A8.
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Old 06-26-2017, 06:47 PM
  #43  
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Guess we just live with AFM for the time being.
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Old 06-26-2017, 06:58 PM
  #44  
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Originally Posted by MichaelO View Post
Guess we just live with AFM for the time being.
I came across DOD (Displacement on Demand) when looking around with HpTuners. Gives the option to enable or disable. I believe you have to write to the ECM though and as they say, this could void the warranty.
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Old 06-27-2017, 12:53 AM
  #45  
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Originally Posted by K1600GT View Post
I came across DOD (Displacement on Demand) when looking around with HpTuners. Gives the option to enable or disable. I believe you have to write to the ECM though and as they say, this could void the warranty.
"void the warranty" NOT a viable solution after paying $80K!!!
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Old 06-27-2017, 09:55 AM
  #46  
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Originally Posted by MichaelO View Post
"void the warranty" NOT a viable solution after paying $80K!!!
I really can't think of a reason why it would void any part of it but who knows.
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Old 06-30-2017, 12:33 PM
  #47  
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Any non factory tune will void the powertrain warranty. If you go to the dealer for a significant powertrain issue, GM will want to know the flash history of the ECM before authorizing the repair. If the flash count does not equal what it should be, the repair will not be paid for by GM and a warrenty hold will be put on the drivetrain.

Originally Posted by K1600GT View Post
I really can't think of a reason why it would void any part of it but who knows.
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Old 06-30-2017, 04:16 PM
  #48  
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Originally Posted by K1600GT View Post
I really can't think of a reason why it would void any part of it but who knows.
Probably because they will have no idea of what was done. The process of validating engine tunes is pretty extensive, and a good deal of it has to do with durability. Someone else starts messing with things, GM isn't responsible. This may seem extreme in some cases, but it really isn't unfair.
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Old 06-30-2017, 04:17 PM
  #49  
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It sucks that something that could potentially keep the drivetrain from having a warranty claim (disabling AFM via tuning) is also going to void that warranty!
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Old 06-30-2017, 10:49 PM
  #50  
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Originally Posted by Boiler_81 View Post
Any non factory tune will void the powertrain warranty. If you go to the dealer for a significant powertrain issue, GM will want to know the flash history of the ECM before authorizing the repair. If the flash count does not equal what it should be, the repair will not be paid for by GM and a warrenty hold will be put on the drivetrain.
i would say switching from 4 to 8 all the time is more detrimental to the the system than just leaving it in 8. I'm pretty sure I could convince a judge of this too especially since GM says it is just for economy.

On on a side note, I just ran 800 miles on my BMW K1600GT with average speed of 76 mph and mpg of 27 mpg. My Z06 did the same distance at 78 mph and 25.8 mpg, just an observation, take it for what it is.
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Old 06-30-2017, 11:06 PM
  #51  
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Originally Posted by Patman View Post
It sucks that something that could potentially keep the drivetrain from having a warranty claim (disabling AFM via tuning) is also going to void that warranty!
The problem is, if there is a power train failure you could have had a power tune that leaned the mixture reversed before bringing the car in for service. All the Dealer can do is check to see if it was messed with.
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Old 06-30-2017, 11:15 PM
  #52  
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Originally Posted by jcthorne View Post
Except it does not work well in the Corvette and causes CEL and codes and non-starts. If it worked properly, it would be a solution but unfortunately it has issues.
I've had zero problems and been using it for 1 1/2 years.

Fingers crossed.
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Old 07-01-2017, 04:12 AM
  #53  
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The Range works fine. If it throws codes it is simple to reset them.
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Old 07-01-2017, 11:20 AM
  #54  
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I agree eliminating the 4V mode would not impact reliability. However, even if you were successful in convincing a judge your modifications had no impact on the system, I can't see how the benefit would outway the cost of time and money to do so.

GM has been very clear that any unauthorized engine management code will void the powertrain portion of the warranty. The safe way to eliminate 4V moe is the Range AFM Disabler.

Originally Posted by K1600GT View Post
i would say switching from 4 to 8 all the time is more detrimental to the the system than just leaving it in 8. I'm pretty sure I could convince a judge of this too especially since GM says it is just for economy.

On on a side note, I just ran 800 miles on my BMW K1600GT with average speed of 76 mph and mpg of 27 mpg. My Z06 did the same distance at 78 mph and 25.8 mpg, just an observation, take it for what it is.
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Old 07-29-2017, 09:54 AM
  #55  
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Great response, Tadge. I was pleasantly surprised when the C7 came out with a V8 engine. When the Dems rammed through the last CAFE rules I thought that would be the end of the Corvette because its size would make it a small car with small car requirements. I thought GM would want to avoid the gas guzzler tax but I appreciate them understanding that the Corvette is not a Kia and we are willing to pay the government's extortion. At least they didn't make it illegal to sell a "gas guzzler" like the Corvette that only gets a combined average of 20.7mpg.

But the changes in the law that were passed several years ago are still getting worse every year. Unless Congress changes the law you are required to increase mileage 5% every year or have us pay 5% more in penalties (tax) every year. So keep trying to keep the cost down but don't kill the Corvette for those of us who have the ability to pay whatever it costs for an American icon. And don't even think of bypassing the law by going electric. Many of us want a car we can take on a road trip and not be limited to 200 miles a day.
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Old 03-10-2018, 02:16 PM
  #56  
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Default AFM / Shake, Shudder issues

I experienced shake, shudder issues , C7 automatic when at steady state and realized it was when AFM had engine in V4. There is a service bulletin for this, #16-NA-175; Shake and/or Shudder during light throttle acceleration between 25 and 80 mph at steady state. It calls for transmission flush, however my torque converter was too far gone and needed to be replaced. I had 23,000 miles and luckily 5 weeks left on the warranty SO if anyone is experiencing this issue have it serviced ASAP.
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Old 03-10-2018, 02:34 PM
  #57  
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There have been lots of posts about the A8 problems. It's just another example of gross lack of professionalism (not to mention dishonesty) by GM in not addressing this problem openly and forthrightly. No wonder people don't trust corporate America.
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Old 03-13-2018, 10:26 PM
  #58  
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I couldn't find it on the Chevy website but a Corvette forum article says the Stingray's EPA fuel economy ratings are as follows:
Manual: 17-city/29-highway/21-combined
Automatic: 16 city/28 highway/20 combined

If AFM was so beneficial, I would have expected the automatic to have significantly improved fuel economy. Typically, ratings only vary 1-2 MPG different between auto and manual transmissions. Is Tadge implying the automatic's EPA rating would be significantly worse than the manual if it weren't for AFM? Something doesn't seem to add up.

Last edited by slickstick; 03-13-2018 at 10:26 PM.
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Old 03-14-2018, 04:29 AM
  #59  
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^^^^

Hmm, don't know what GM is implying or not BUT do you think a torque converter moving lots of oil around to couple the engine and drivetrain, with many clutch plates internally and all that plumbing and pumps to activate, many more gears (albeit sun and ring gears,) is not wasting energy compared to always in mesh simple helical gears in an M7 that we engage manually ourselves!

Comparing base Stingrays with auto and M7, the auto needs a trans cooler to deal with the inefficiency, the M7 has none! Yep the "performance oriented C7 M7s" have a trans cooler but unless your driving aggressively the trans temps are not very high. That trans cooler is just putting more of the gasoline energy into the air!

EPA mpg numbers for the M7 could be in ECO mode where V4 actiavtes. (An which I have never used in my 11 month old Grand Sport and only did in my 2014 Z51 to check mpg difference a few times and could feel the transition on the highway!)

Looks like the C8 mid engine will use a dual clutch, essentially standard trans that is computer (or paddle) activated. At least that is what it says Tremic will provide! Sounds like no more "slush box" for the Vette!

Assuming I get one, will be my first DD in ~60 years without a clutch peddle!

Last edited by JerryU; 03-14-2018 at 04:46 AM.
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Old 03-14-2018, 10:32 AM
  #60  
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It depends how you drive but based on testing the auto with afm off/on it gets 1 to 2 mpg better using afm. The epa numbers for the manual appear to be with afm off.
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