CARB approved DOD/AFM delete kit

[Mooseman]

Found out about this from the Caprice forum and would be good to know for those living in CA and other emissions enforcing states on deleting DOD/AFM.

https://ww2.arb.ca.gov/sites/default/files/aftermarket/devices/eo/d-752-8.pdf

2005-2017 GEN4 6.0/6.2L DOD DELETE SYSTEM FOR NON-VVT ENGINES | LPP802116 | Livernois Motorsports

2005-2017 GEN4 6.0/6.2L DOD DELETE SYSTEM FOR NON-VVT ENGINES

www.livernoismotorsports.com

The kit seems a bit overpriced however they probably put up for the costs of getting this certification and there's the tuner that's included. As mentioned in that post, it would be a good idea to replace the other 8 lifters and I would throw in a new timing chain set too.

 

[c good]

That seems like a pretty reasonable price for everything that comes in the kit. Eventually my Envoy will be replaced...hopefully not for a long time. I was looking into the pre 2006 models specifically to avoid the DOD/AFM problems. This opens up a bigger market now.

 

[CajunWon]

$1k kit + labor at your local shop. Guess $3,500 total.
Does not reduce effectiveness of the DOD system. Because the DOD AFM systems are totally ineffective.

 

[spfautsch]

That's not a bad price considering what's included (primarily ECM reprogramming).

I found this thread because lately I've been weighing the pros and cons of an AFM delete, versus simply replacing my 215k mile DOD lifters and trays and going on with life. Hopefully for another 215k miles.

A few motivating factors are that I already own several sets of low mileage LS7 lifters that could replace the non-DOD lifters "while I'm in there". Also, I really, really don't want to change the cam.

My only concern - potentially unwarranted, is they specify this for the 6.0/6.2. I wonder if there are any considerations there for programming the 5.3 ECM?

Personally I'm leaning towards replacing the DOD lifters with new DOD lifters, and not a lot else else. The prospect of pulling the radiator and timing set isn't particularly appealing, not to mention having to buy another tool to realign the timing cover the right way.

I'm personally somewhat confused as to how the cam "must be replaced". If the DOD lobes are ground differently then I see no reason why the same "potential misfire" scenario wouldn't be present on every LH6. The roller tips on the DOD lifters are the same diameter as the non-DOD lifters, and as far as I'm aware the pushrods are of the same length. This would mean the DOD lifters present the same valvetrain geometry as the non-DOD cylinders, which would mean there would be no difference in lift and duration when not deactivated versus using non-DOD lifters. So why wouldn't the purported 25psi lower compression be evident on a non-deleted LH6? I think it's just another fear-based money grab to sell you a cam while you have your credit card out of your wallet.

 

[spfautsch]

Update, after a short bit of deliberation and consulting with my mechanic friends I pulled the trigger on a parts order from RA. Complete engine gasket kit (including valve guide seals), head bolts, 8 new DOD lifters, 4 guide trays and a filter screen for $550 shipped (after some store credits I had accumulated).

As soon as I get my "historic vehicle" '95 Y-body back into daily driver service I'll tear into this project. It was always going to be necessary but life changes have accelerated the need. So there's no time like the present!?! As with 2024, I will be driving this vehicle ~1700 miles round-trip to our usual Florida vacation destination this August.

 

[Mooseman]

It's an idea but I would still tune the DOD off or use a Range device, which is removable and won't affect E-testing, to prevent it from activating. It is such a failure prone system for so little savings that it's not worth keeping active.

 

[spfautsch]

While I respect what you're saying, I'm not sure I'm in complete consensus that the AFM system is massively failure prone in and of itself.

I doubt this lengthy dialog will change your mind, but you should take it into deep consideration the next time you parrot out a claim that the AFM system was doomed to fail from the factory.

Part of the dialog I had with my mechanic friend was regarding his 2007 Silverado with the iron block version of the LH6. While it's only racked up 103k miles, he's never had an issue with the AFM functionality and it's as quiet as the day he drove it off the dealer's lot.

As I was pressing him for details about what oil he puts in cars he went into a sales-pitch fueled description of the no-name synthetic blend he "swears" by that they sell to customers (subtext here is high profit margin). Having seen an empty jug of Mobil 1 5w30 "standard" in his trash can, I then asked him what oil he runs in his personal vehicles. Immediately an awkward silence overtook the office area before I stopped him and told him he didn't need to answer. I get it, they have mortgages and stuff to pay, but I wouldn't let him put that no-name oil in my lawn mower even if he donated the materials and labor.

My point here is that the vast majority of people who come to the internet to complain about failures neglect vehicles, sometimes by way of little of their own negligent culpability. My personal opinion is that anyone who pays a business to change their oil has no earthly idea what crap oil the "mechanic" is refilling with and they're getting what they deserve. I have never had an oil change on a vehicle I owned that I didn't do personally. There's a reason for that.

All the indicators I've seen on my particular vehicle (an '06 Envoy Denali XL) lead me to believe it's been relatively well maintained. It uses about 2 to 2-1/2 quarts of oil on a 5k mile oil change interval where the filter is obviously always replaced. Though I know little about whether a previous owner has used a Range(r?) device to disable AFM, it runs extremely well for an engine with >200k miles. I regularly get ~17 mpg and it has the 3.73 locker diff and I drive 7mph over the speed limit everywhere, so that's saying something.

Anyone can buy a vehicle that's been neglected through no fault of their own. But it doesn't mean every vehicle will be neglected, which increases the likelihood of a lifter failure. In my not so humble opinion the AFM system on these will fail almost inevitably if the owner runs junk oil and only has it changed when the computer tells them to. It will also fail quite spectacularly if you run them out of oil.

I've done a bunch of reading on this subject, and everything I've collected indicates that these lifters only fail catastrophically when they experience a scenario where the collapsible section doesn't receive adequate oil pressure & volume to completely retract the locks before the lifter in question reaches the end of the cam's base circle and experiences full valve spring load.

I'm going to press forward with my plan to simply replace lifters, trays, valve stem seals and the VLOM oil filter along with the top-end gaskets that I happen to remove in the process. It may come back to bite me. If that's the case I'll have zero hesitation reporting back as such. But my hope is it goes another 100-150k miles. I doubt I'll live long enough to see another 214k out of it.

 

[Mooseman]

I hear where you're coming from and agree to a certain extent. However, all oil that is used today, whether high end boutique oil to unbranded barrels used at quick lubes, all have to meet current API standards (currently SP and SQ) so they can also use it in newer and older vehicles, or at the very least SN, which can be used in 2020 and older vehicles. Any oil that is sold today is better than any oil that was sold 20 years ago when our vehicles first came out (SL/SM).

Certainly oil can play a major role in making anything last longer. I take care of a fleet of government vehicles that almost never get oil changes by mileage but by age. As an example, I have a 2011 Traverse with the infamous 3.6L with the failure prone timing chains. It only has 87k km and is running mint. That's roughly only 6k km per year and it usually gets oil changes every 6 months regardless of km, otherwise it would be at 8k km. So basically, it always ran on new hardly used oil. I'd have no problem buying this vehicle despite the known engine issues.

So if your truck was in a similar situation where the oil was changed mostly on time rather than mileage or changed every 5k miles regardless of what the OLM said, it would definitely reduce wear. However, with extended oil change intervals now recommended and long OLM periods, this can introduce more wear.

GM's literature at the time touted that DOD would save only about 5% in fuel. My own testing with the system enabled and disabled showed a very negligible difference in fuel consumption. And these were the first years for DOD so failures were more common, and likely more prevalent in vehicles that actually followed the OLM or recommended oil changes and would be precipitated even more even if a little neglected, which normally failures don't happen in regular engines. Personally, I don't think it's worth the trouble and risk so I disable it, same as stop/start. Even CARB has recognized this and approved a kit to remove and disable it, which is unheard of.

 

[spfautsch]

While it's possible I'm twisting your words a bit, I would strongly disagree that the API-graded blends the quick-lube places purchase in 275 gallon skid-totes are remotely equivalent to off-the-shelf synthetics that contain only PAO base stocks or better. My opinion is that those API ratings serve mainly to satisfy the manufacturer's desire for an "out" against warranty claims. Likewise, I have to assume Dexos I/II while of seemingly stringent standards on the surface, are considered licensing agreements for a reason (subtext: $$$).

The science of PAO based oil isn't new, certainly predating the API specs. It was a significant factor in making the Merlin powered P-51 fighters of WW2 viable at very high altitudes and airspeeds. It worked well and maintained measurably consistent viscosity both at sub-atmospheric climates of 15-25k feet and at 1-bar climates down on the ground in the hot desert sun or on an aircraft carrier in the south pacific.

There are a lot of variables and the science to validate those variables is expensive and changes almost daily because our understanding of the science continues to evolve even though it's some of the most base science the 21st century has been able to render for analysis. In the current accepted realm of quantum physics it's so primitive it fails to warrant the vaguest mention. Yet an overwhelming portion of our society relies on it for it's day-to-day activities.

I'm not an independent, or socially funded science lab. What I am is someone with common sense and a calculator. I think GM's claim of 5% is highly conservative, and I feel it warrants independent verification.

As such my next project is to test your brake booster plug idea on that MAP sensor and see if it works without setting a code while simultaneously disabling AFM. I happened to have a used booster check valve, which when coupled with a vacuum port cap should keep my brakes working as designed. Found another cap that fit over the MAP sensor port to keep junk out of it as it's currently zip-tied to one of the body harnesses. If it works I'll report back with pictures. As I religiously log actual fuel consumption against mileage, it should only take a few tanks worth of data to see if there's a pattern to observe.

 

[Mooseman]

You just need to unplug the vacuum sensor on the brake booster, not the engine's MAP sensor. And it's just the electrical connector, not the vacuum line. It will give a code for it but will not affect anything except inhibit AFM. That's all that sensor is for.

Oh, and while it's disabled, you will also notice a lower oil consumption.

 

[spfautsch]

You just need to unplug the vacuum sensor on the brake booster, not the engine's MAP sensor. And it's just the electrical connector, not the vacuum line. It will give a code for it but will not affect anything except inhibit AFM. That's all that sensor is for.

I understand that completely. I referenced it as a MAP sensor because that's what it is - a Manifold Absolute Pressure sensor. Except the manifold this one measures is the brake booster body. I was simply trying something different from disconnecting it electrically to see if it would maybe skirt setting a code. Unfortunately plugging the hole it occupies in the brake booster and leaving the MAP sensor open to 1 bar / atmosphere also set a code (P0556-00). Oh well.

Oh, and while it's disabled, you will also notice a lower oil consumption.

I've read a dozen different theories on why this is. Can you elaborate on what your personal belief/s is/are?

 

[Mooseman]

Because when I deleted the DOD in my 9-7x, oil consumption went down, as well as in the L76 in the 6.0L in the 2010 Avalanche I once owned also went down when I tuned it out in that one.
It's documented all over the internet. There are many reasons, one of which is the pumping action from the dead cylinders when in 4 cyl mode that lets oil into the cylinder. And it's because of THAT that DOD was programmed from the factory to reactivate all cylinders after 10 minutes at most.

This thread has gone off course, which was to talk about a CARB approved delete kit, not to discuss the merits of DOD/AFM. This thread is now locked.