How often does AFM crash an engine?
Thread Starter
Racer
Joined: Jul 2019
Posts: 444
Likes: 92
From: Truckee, CA
How often does AFM crash an engine?
I've frequently read that AFM can cause a valve train to crash. How often does this actually happen? For example, does someone complain about it here about once per year or every five years? I doubt if anyone has any hard data about this, although that would be ideal.
Popular Reply
Jul 27, 2024, 10:07 AM
Race Director
Joined: Apr 2000
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From: Texas
Let's see......how many millions of the LT1 and the derivatives are out there? yeah.......a LOT. Are there unfortunate issues on occasion? Yes. Is it something that happens regularly? I'll say no or 1) the internet would be on fire 2) there'd be a recall of some sort and 3) in this sue-happy world I'd imagine a class action suit.
We might have an earthquake, a tornado, and a hail storm too.
Enjoy the car and quit worrying.
We might have an earthquake, a tornado, and a hail storm too.
Enjoy the car and quit worrying.
Pro
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From: Sarasota, Florida
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Great question if you ask me 🤔
Racer
Joined: Sep 2020
Posts: 388
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From: New Berlin
I'd guess warranty data is held closer than nuclear launch codes, but you can be sure the data exists. When I worked in chevy service in the early 80's I recall "Automotive News" had cost data printed for many makes - how they got it, who knows. I can only recall the Jag V12 was at the top by a long ways (my memory is it was in the thousands - wild in 1980's dollars). It might be easier to pry the data loose from the private warranty companies. They may not even care, as they just charge enough and go out of business fast enough that paying for some program to keep track doesn't pay!
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Let's see......how many millions of the LT1 and the derivatives are out there? yeah.......a LOT. Are there unfortunate issues on occasion? Yes. Is it something that happens regularly? I'll say no or 1) the internet would be on fire 2) there'd be a recall of some sort and 3) in this sue-happy world I'd imagine a class action suit.
We might have an earthquake, a tornado, and a hail storm too.
Enjoy the car and quit worrying.
We might have an earthquake, a tornado, and a hail storm too.
Enjoy the car and quit worrying.
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Le Mans Master
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If it was a statistically impactful number there would be enough complaints to have a recall. NHTSA uses pattern of defect (in addition to safety and regulatory) when a recall is issued. The number of failures for a pattern of defect is higher than the other two (where few cases are enough to drive a recall for safety and regulatory can have "zero cases" as its just factual), I don't think they have a number but its over a couple of percentage points of failure. So if there are millions of engines you'd need at least a few thousand failures.
8th Gear
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Don’t know what the percentage is but if it happens to you that percentage is 100%. I am one of those guys that buys an extended warranty on cars. For the cost of the Range device, it is cheap insurance and could help prevent a lot of hassle and frustration.
Team Owner
Joined: Jul 2004
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From: Hartford WI
How does that work? If the lifter is weak and failure prone, whether it is pumped up or not, what is the difference?
Le Mans Master
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I always get upset when it rains if the weather report is 0% chance, because technically anything over 0% chance means I can experience something, but 0% is 0%.
If the valve issue is over 0% it doesn't matter if you experience it or not, its greater than 0% so you could. In theory/math.
If the valve issue is over 0% it doesn't matter if you experience it or not, its greater than 0% so you could. In theory/math.
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Has there been engine failures due to something going wrong with the AFM system - yes and some stories have been posted on the forum. Just what percentage those failures represent - that is unknown for the average person.
Pro
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From: Sarasota, Florida
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Why not just start a sticky with a survey question that records the percentage?
Racer
Joined: Apr 2020
Posts: 425
Likes: 272
From: Cape Coral,FL
AC Delco made a YouTube video about this happening it's called a missed timed event. In the event this happens you're cooked. Now how often, I don't know, like others have said the range device is cheap insurance. Even without the worry of a failure I don't like the fact of 4 cylinders being shut down. It's hard on the drive train including the tq convertor and tq tube couplings. The drive train has to compensate for the vibration. Here is the video of you would like to watch it explains the AFM
Thread Starter
Racer
Joined: Jul 2019
Posts: 444
Likes: 92
From: Truckee, CA
Thanks for all of the responses.
My reason for asking about AFM failure rates is I read about problems caused by AFM being activated after a long period of being inactivated by a Range or similar system. Apparently parts of the AFM system don't get lubricated as much when AFM is deactivated.
I recently installed a Range and I like not having the 4 cyl to 8 cyl lag. Since there doesn't seem to be enough data available to compare the risk of damage with and without a Range, I think I will drive without the Range for a couple days per quarter or something like that to keep it at least semi lubricated.
My reason for asking about AFM failure rates is I read about problems caused by AFM being activated after a long period of being inactivated by a Range or similar system. Apparently parts of the AFM system don't get lubricated as much when AFM is deactivated.
I recently installed a Range and I like not having the 4 cyl to 8 cyl lag. Since there doesn't seem to be enough data available to compare the risk of damage with and without a Range, I think I will drive without the Range for a couple days per quarter or something like that to keep it at least semi lubricated.
Last edited by DugT; Jul 28, 2024 at 02:43 PM.
Team Owner
Joined: Jul 2004
Posts: 28,475
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From: Hartford WI
Thanks for all of the responses.
My reason for asking about AFM failure rates is I read about problems caused by AFM being activated after a long period of being inactivated by a Range or similar system. Apparently parts of the AFM system don't get lubricated as much when AFM is deactivated.
I recently installed a Range and I like not having the 4 cyl to 8 cyl lag. Since there doesn't seem to be enough data available to compare the risk of damage with and without a Range, I think I will drive without the Range for a couple days per quarter or something like that to keep it at least semi lubricated.
My reason for asking about AFM failure rates is I read about problems caused by AFM being activated after a long period of being inactivated by a Range or similar system. Apparently parts of the AFM system don't get lubricated as much when AFM is deactivated.
I recently installed a Range and I like not having the 4 cyl to 8 cyl lag. Since there doesn't seem to be enough data available to compare the risk of damage with and without a Range, I think I will drive without the Range for a couple days per quarter or something like that to keep it at least semi lubricated.
Drifting
Joined: Jul 2017
Posts: 1,369
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From: Kingston, Ontario
A range device wont even prevent it from failing. Just because the lifters don't get used doesn't mean they won't break. They could just fall right out amd cause damage.
The range device shouldn't be seen as preventing failure but just preventing the poor transition between V4/V8 modes.
Your AFM tech can still break even if you don't use it. Its just another that can go wrong but nothing we can do about it. The chance does seem to be pretty low so I wouldn't worry about it.
The range device shouldn't be seen as preventing failure but just preventing the poor transition between V4/V8 modes.
Your AFM tech can still break even if you don't use it. Its just another that can go wrong but nothing we can do about it. The chance does seem to be pretty low so I wouldn't worry about it.
Melting Slicks
Joined: Feb 2018
Posts: 2,184
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From: North Texas
"My reason for asking about AFM failure rates is I read about problems caused by AFM being activated after a long period of being inactivated by a Range or similar system. Apparently parts of the AFM system don't get lubricated as much when AFM is deactivated".
If this was true, then the 7 speed transmission model cars would be failing all the time since they never go into V4 mode except when you select Eco mode which I doubt not many people do.
If this was true, then the 7 speed transmission model cars would be failing all the time since they never go into V4 mode except when you select Eco mode which I doubt not many people do.