AFM Delete and California Smog

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Dustin Jackson

Dustin Jackson

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Those guys were full of it, if worse comes to worse you buy a used unmarried canned carb certified tuner, hypertech, etc and put that on it to pass smog and then put the bb tune back on. I did it, it passed. Relax
@Doubeleive My coworker picked up an Avalanch with a lifter problem and so he was following in my footsteps but was hesitant since it wasn’t proven that my motor would pass smog with the AFM delete. I told him if he pays for half of the smog we can test with my Tahoe and sure enough it passed this morning just fine
 

adventurenali92

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Interesting input from everyone so far. I’ve had my 2006 LQ4 autocal tuned via blackbear PF since late 2017 I believe, and while my engine is not to totally modified yet, I have never had an issue with passing smog even with my spectre intake setup and the magnaflow muffler in place of the OEM one. Kinda depends on where you go and whether or not they actually inspect things. Only year that happened to me was when I forgot to have it smog tested up in big bear. He inspected some things but I dont think found anything he could to fail me on. I passed as that years DMV tags and such.

I am planning some mild power upgrades and will be re tuning. As far as I’m aware all carb complaint upgrades will not raise any flags on an inspection. As long as your check engine light is not on within a couple days leading up to the test being done I shouldn’t think you’d have anything to worry about?

Edit: read that you passed fine. Excellent that it wasn’t difficult.
 

smwalker

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What we have derived from a year of passes and fails for modified software is this. The SMOG computers seem be ignoring tunes on any GM vehicle that comes with a AFM engine. So long as the only thing your tune does is turn off the AFM system. Start messing with turning off OBD monitors and you will fail.

We have seen passes on the L77, L76 and L99 engines that have DOD / AFM tuned out.

And it is only logical why they excluded them. Imagine all the Trucks and SUV out there that have had the DOD tunes out because of the failed AFM system. They would have had a couple thousand people every year throwing up a stink on why thier SUV could not be drive in CA any longer because of GM's screwed up system.

So if you got an AFM engine for now you got a free pass. Just do not go nuts with the tunes, all monitors still have to report and complete to pass a SMOG in CA.
 

Geotrash

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What we have derived from a year of passes and fails for modified software is this. The SMOG computers seem be ignoring tunes on any GM vehicle that comes with a AFM engine. So long as the only thing your tune does is turn off the AFM system. Start messing with turning off OBD monitors and you will fail.

We have seen passes on the L77, L76 and L99 engines that have DOD / AFM tuned out.

And it is only logical why they excluded them. Imagine all the Trucks and SUV out there that have had the DOD tunes out because of the failed AFM system. They would have had a couple thousand people every year throwing up a stink on why thier SUV could not be drive in CA any longer because of GM's screwed up system.

So if you got an AFM engine for now you got a free pass. Just do not go nuts with the tunes, all monitors still have to report and complete to pass a SMOG in CA.
VERY helpful tidbit of knowledge. Thank you.
 

2006Tahoe2WD

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Anyone please correct if I'm wrong. The BB solutions provide the CVN/etc. needed so that the recent (after July? 2021) CARB testing will not detect that the two files it checks are not what the factory provided. In other words it passes that part of the test.

(for 2016 5.3 Tahoe)
The more important question(s) for me are are the pros and cons to the various lifter/cam scenarios after the "software" stops allowing oil to the VLOM:
1 - keep the current used DOD and non-DOD lifters (potential issue(s) worn cam and worn DOD lifters)
2 - replace the current DOD lifters with new DOD lifters (standard lifters on the DOD lobes doesn't work well, the DOD lobes are different producing claimed error codes and/or poor runnng, this is in need of confirmation)
3 - replace cam with all standard lobes (possibly a slightly bigger cam) with all "standard" lifters (clean solution but hard to go back for CA resale)
 
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Dustin Jackson

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In the testing that I did in this thread and with my coworker it seems that they do not check the computer pass emission monitors but this is not indicative of the SMOG process everywhere, just in the couple of smog shops that we tested in my city in California. I have heard that BB tune is done very well and shouldn't raise any flags but a dealership with warranty hours on the line would probably dig deeper into ECU tampering than a SMOG shop.

Myself and others I've seen have still encountered lifter collapsing and/or turning in the tray situations with only AFM tuned off but also there are a lot of others that have had great success just by tuning it off and leaving the AFM lifters and cam in. I would say that tuning AFM out will reduce your chances of lifter failure but to have the least chance of lifter failure I would swap the lifters, cam, and valley cover for non-AFM versions.

I don't think that you will have a problem with reselling the Tahoe after an AFM delete
 

Marky Dissod

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(for 2016 5.3 Tahoe)
The more important question(s) for me are are the pros and cons to the various lifter/cam scenarios after the "software" stops allowing oil to the VLOM:
1 - keep the current used DOD and non-DOD lifters (potential issue(s) worn cam and worn DOD lifters)
2 - replace the current DOD lifters with new DOD lifters (standard lifters on the DOD lobes doesn't work well, the DOD lobes are different producing claimed error codes and/or poor running, this is in need of confirmation)
3 - replace cam with all standard lobes (possibly a slightly bigger cam) with all "standard" lifters (clean solution but hard to go back for CA resale)
For ANY vehicle, with either version of cylinder deactivation:
After disabling cylinder deactivation in the ecm, discard the complicated lifters and replace them with simple lifters.
The older the camshaft, the more urgently the camshaft should be replaced. An old worn out camshaft on new unworn lifters is a bad idea.
May as well replace / upgrade the camshaft with a slightly better cam that does not feature cylinder deactivation.
 

Marky Dissod

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Myself and others I've seen have still encountered lifter collapsing and/or turning in the tray situations with only AFM tuned off, but also there are a lot of others that have had great success just by tuning it off and leaving the AFM lifters and cam in.
Statistically speaking, eventually, we can all guess with fair certainty which type of lifter will tend to fail first.
Turning off cylinder deactivation will let the dual-mode lifters last longer, but given enough time, the single mode lifters will tend to outlast them.
... tuning AFM out will reduce your chances of lifter failure, but to have the least chance of lifter failure I would swap the lifters cam and valley cover for non-AFM versions.
I'd rephrase it like this:
The less cylinder deactivation, the longer the dual-mode lifters will last, because their inherent flaws are being minimized, although not completely avoided.
The design of dual-mode lifters themselves is the root of the problem, even with cylinder deactivation disabled.
The simpler lifters are of a more robust design, and will nearly always outlast the dual-mode lifters, given enough time.
I don't think that you will have a problem with reselling the Tahoe after an AFM delete.
You'd have a harder time reselling the the Tahoe without the AFM delete.
Deleting the AFM makes it MORE valuable, and makes it hold more of its value even longer.
 

2006Tahoe2WD

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For ANY vehicle, with either version of cylinder deactivation:
After disabling cylinder deactivation in the ecm, discard the complicated lifters and replace them with simple lifters.
The older the camshaft, the more urgently the camshaft should be replaced. An old worn out camshaft on new unworn lifters is a bad idea.
May as well replace / upgrade the camshaft with a slightly better cam that does not feature cylinder deactivation.
Makes sense. The Tahoe I'm looking at has 68k miles.

I wonder if the ecm can detect the slightly if any difference in the cam. I think not because I haven't seen a mention of it on the internet.
The issue I'm still thinking of is reselling in CA and I don't pass the visual or if somehow the buyer finds out. I know that's paranoid but it is a thing. I would probably opt to modify the stock VLOM to help with passing the visual.
The remaining issues are:
- cost and getting a place to make the changes (cam and lifters/etc.)
- other while-you-are-in-there (e.g. get heads cleaned up and checked)
- trans torque converter
- I think leave the big oil pump in - I don't think it hurts anything
 

2006Tahoe2WD

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Statistically speaking, eventually, we can all guess with fair certainty which type of lifter will tend to fail first.
Turning off cylinder deactivation will let the dual-mode lifters last longer, but given enough time, the single mode lifters will tend to outlast them.
I'd rephrase it like this:
The less cylinder deactivation, the longer the dual-mode lifters will last, because their inherent flaws are being minimized, although not completely avoided.
The design of dual-mode lifters themselves is the root of the problem, even with cylinder deactivation disabled.
The simpler lifters are of a more robust design, and will nearly always outlast the dual-mode lifters, given enough time.You'd have a harder time reselling the the Tahoe without the AFM delete.
Deleting the AFM makes it MORE valuable, and makes it hold more of its value even longer.

Thanks and yes. Better to get the dual mode lifters out of there and probably don't put new lifters to ride on an old cam.
I agree more value with DOD delete but in CA you have to pass smog or no sale.
 

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