Questions about bypassing AFM / any risks?

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Sarah_279

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So, can I ask a stupid question? I'm using a Range device to bypass AFM on my '19 5.3 Tahoe. Purchased it new in September and have about 2900 miles on currently, hasn't had its first oil change yet. But I'm starting to think about oil change intervals and the best type of oil, etc. I started using the Range device immediately when I brought the truck home.

From what I understand, (and I'm still learning/reading so bear with me) vehicles with AFM use high volume oil pumps. When you bypass AFM, what happens to all that extra oil? Could disabling AFM potentially mess with oil pressure sensors? I googled around trying to find an answer but I'm not finding anything. Maybe this is a non-problem and I'm over-thinking it. (you can roll your eyes, I won't be offended)

Just trying to do the right thing because I want to keep my Tahoe forever.
 

Whipped500

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I would like to hear thoughts on this as well.

I thought what I was reading was that the biggest problem was not changing the oil often enough? The dirty oil was screwing with something? I also thought I read that somewhere around 2012, they refined the system to work better? I'm about ready to order a tahoe and frequent oil changes and a range device was going to be on my to do list.
 

89Suburban

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I run a Range device also. Keep in mind that if you do so and you live in an area that requires emissions testing, it will affect it. Unplug it and drive it for at least a week or so the computer can relearn before any testing is done.
 
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swathdiver

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So, can I ask a stupid question? I'm using a Range device to bypass AFM on my '19 5.3 Tahoe. Purchased it new in September and have about 2900 miles on currently, hasn't had its first oil change yet. But I'm starting to think about oil change intervals and the best type of oil, etc. I started using the Range device immediately when I brought the truck home.

From what I understand, (and I'm still learning/reading so bear with me) vehicles with AFM use high volume oil pumps. When you bypass AFM, what happens to all that extra oil? Could disabling AFM potentially mess with oil pressure sensors? I googled around trying to find an answer but I'm not finding anything. Maybe this is a non-problem and I'm over-thinking it. (you can roll your eyes, I won't be offended)

Just trying to do the right thing because I want to keep my Tahoe forever.

https://media.gm.com/media/us/en/gm...15/typeId/c/currentChannelId/Most Recent.html

http://gmauthority.com/blog/gm/gm-engines/l83/


Your engine has a variable displacement oil pump. All of your AFM components are vastly improved over the previous generation making the system much more reliable. Because of the increased power of the Gen V motors, AFM can have a duty cycle of up to 50% instead of about 10% for the previous Gen IV motors.

There are no oiling problems when AFM is not in use, maybe over the long haul but not with regular use. Look for an oil passage diagram for your engine.
 
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Sarah_279

Sarah_279

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I thought what I was reading was that the biggest problem was not changing the oil often enough? The dirty oil was screwing with something? I also thought I read that somewhere around 2012, they refined the system to work better? I'm about ready to order a tahoe and frequent oil changes and a range device was going to be on my to do list.

Yep, I saw a few articles that said similar. I also thought I read where there used to be an additional filter that would get clogged, causing problems. But they eliminated these filters in the '19's. (Too much Googling, now I can't find where I saw that, so take it for what it's worth.)


I run a Range device also. Keep in mind that if you do so and you live in an area that requires emissions testing, it will affect it. Unplug it and drive it for at least a week or so the computer can relearn before any testing is done.

Thank you for reminding me about this, I'm in Pennsylvania and we have to do emissions every year. It's easy to forget that the Range is plugged in.
 
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Sarah_279

Sarah_279

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https://media.gm.com/media/us/en/gm/bcportal.html/currentVideoId/3352092792001/pnId/15/typeId/c/currentChannelId/Most Recent.html

http://gmauthority.com/blog/gm/gm-engines/l83/


Your engine has a variable displacement oil pump. All of your AFM components are vastly improved over the previous generation making the system much more reliable. Because of the increased power of the Gen V motors, AFM can have a duty cycle of up to 50% instead of about 10% for the previous Gen IV motors.

There are no oiling problems when AFM is not in use, maybe over the long haul but not with regular use. Look for an oil passage diagram for your engine.

Thanks for this info.
I guess I'm just wary of AFM technology in general because my last vehicle had it and would do all sorts of crazy *$@! while going down the road. But this stuff interests me so I want to learn.
It is the future, after all. (yay?)

Ideally, I'd like to keep my lifters happy, (don't we all) but hopefully not at the cost of possibly stressing other components of the AFM system, if that makes sense.
 

swathdiver

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Thanks for this info.
I guess I'm just wary of AFM technology in general because my last vehicle had it and would do all sorts of crazy *$@! while going down the road. But this stuff interests me so I want to learn.
It is the future, after all. (yay?)

Ideally, I'd like to keep my lifters happy, (don't we all) but hopefully not at the cost of possibly stressing other components of the AFM system, if that makes sense.

It's cool technology but adds complexity and more stuff to break over the long haul. When those electronic solenoids fail and fall out of timing, they cause the lifters to fail. Course, the lifters can fail on their own but the new designs have all but eliminated that. The newest engines have Dynamic Fuel Management and instead of shutting off just the same 4 cylinders, I believe all of the cylinders can be shut down, at least seven anyway, the solenoids now are inside the motor.

Mine has the latest parts but is programmed off and will eventually be removed.
 

kiwi

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I decided to change my oil every 5000 miles. Not very pricey, and def better to engine. AFM enabled
 

jeffbco

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Yep, I saw a few articles that said similar. I also thought I read where there used to be an additional filter that would get clogged, causing problems. But they eliminated these filters in the '19's. (Too much Googling, now I can't find where I saw that, so take it for what it's worth.)




Thank you for reminding me about this, I'm in Pennsylvania and we have to do emissions every year. It's easy to forget that the Range is plugged in.
I run a Range device also. Keep in mind that if you do so and you live in an area that requires emissions testing, it will affect it. Unplug it and drive it for at least a week or so the computer can relearn before any testing is done.
Only reason to remove the Range device before emissions testing is so that emissions tester can use the OBD port for his tester. No reason to drive for a week before testing either. Range doesn't leave any indication of its use after unplugged.
 

89Suburban

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Only reason to remove the Range device before emissions testing is so that emissions tester can use the OBD port for his tester. No reason to drive for a week before testing either. Range doesn't leave any indication of its use after unplugged.

It absolutely affects the test, at least in my case it did. Something about the readiness monitors. If interested, please see the related discussion on this here:

https://www.tahoeyukonforum.com/thr...nnbs-gmt900-tahoe-yukon-today.44151/page-1819
 

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