V4/V8 Mode Vibration

[Stuart3256]

I have a 2007 Tahoe 4x4 5.3L
When slowing down I have nothiced an increasing vibration when going from V4 to V8 mode.

What is wrong?
How can I fix it?

Thanks!!

 

[iamdub]

Either the AFM system is beginning to have issues or you have a blown and flattened motor mount or both. Both are very common and highly likely. If it were me, I'd disable the AFM with a tune (custom or handheld) or get the Range disabler device. Kill the AFM before it kills your motor!

 

[PG01]

Either the AFM system is beginning to have issues or you have a blown and flattened motor mount or both. Both are very common and highly likely. If it were me, I'd disable the AFM with a tune (custom or handheld) or get the Range disabler device. Kill the AFM before it kills your motor!

^^^^^this x1000

 

[Stuart3256]

Either the AFM system is beginning to have issues or you have a blown and flattened motor mount or both. Both are very common and highly likely. If it were me, I'd disable the AFM with a tune (custom or handheld) or get the Range disabler device. Kill the AFM before it kills your motor!

All I have to do is program it out? I saw a “delete kit” that include lifters and a bunch of other stuff.
How do I know if motor mount is messed up?

Thanks for your help!!

 

[kwOH]

https://rangetechnology.com/afm-disabler/

 

[iamdub]

All I have to do is program it out? I saw a “delete kit” that include lifters and a bunch of other stuff.
How do I know if motor mount is messed up?

Thanks for your help!!

Deleting it is the best way because you remove the actual failure-prone components from the engine. Disabling it is a second-best way because you at least keep the system from engaging. But, the crappy lifters (what usually fails and causes damage) are still in place.

To test the engine mount, pop the hood and watch the motor through the gap between the hood and the cowl. Hold the brake firmly with the gear in "D". Jab the throttle pedal about 1/4-1/2 way. If the motor jumps up on the left side then slams back down (you'll feel it, too), then you have a busted driver's side mount. The passenger side lasts much longer because it's only under tension in when the car is in reverse. Although, it may be "popped" and it's fluid leaked out (orangy/rust-colored stains).

 

[okfoz]

I have almost 150K on my 2007 and although I get the groan when it goes into 4 cyl mode I never really realize it goes between 4 & 8. I have done an oil clean-out where they got all the sledge from my engine and that seemed to clear up some issues I had like fuel mileage.

John

 

[Stuart3256]

I have almost 150K on my 2007 and although I get the groan when it goes into 4 cyl mode I never really realize it goes between 4 & 8. I have done an oil clean-out where they got all the sledge from my engine and that seemed to clear up some issues I had like fuel mileage.

John

How much did that cost to do the oil clean out??

 

[okfoz]

I think it was like $50-$70 or so... I had one car that was running rough, like it had a sticky valve and it cleared that up... not immediately, but it had the condition for about 1000 miles and then after the cleanout it went away after 50 or so miles...

My oil change place does them... It is like doing two oil changes. They drain your oil, they put this cleanout stuff in your crankcase, then you run your engine for 10 min or so. They drain that and fill with oil then you are good to go. The oil in my tahoe at 150K remains very clear even after 3/4000 miles but I have been using synthetic too...

 

[tiktok4321]

Even using Synth only you gotta clean out the engine? I like the concept of the AFM, and I just went through a major overhaul replacing my camshaft and all the lifters and trays - a gift from the previous owner. I had been using standard 5w30 per the manual, but the guy that did my costly, timely rebuild said to always use synthetic and never use detergents.

I don't think I want to disable my AFM if I can keep the system working well. But I don't want to spend another $5K on an engine overhaul in the future. Is there any other preventative maintenance or should I go ahead and hit the delete button? AND - Can I even delete/disable/remove the AFM if I have a Hybrid? Is it integral to the Hybrid control system?

 

[Lightning 95]

I have what seems to be not normal V-4 vibration. Is that covered under the powertrain warranty? I can bypass it around town by running the trans in M5 for now though.

 

[Cavan806]

Either the AFM system is beginning to have issues or you have a blown and flattened motor mount or both. Both are very common and highly likely. If it were me, I'd disable the AFM with a tune (custom or handheld) or get the Range disabler device. Kill the AFM before it kills your motor!

Will the use of the Range AFM disabler affect my BB tune?

 

[iamdub]

I have what seems to be not normal V-4 vibration. Is that covered under the powertrain warranty? I can bypass it around town by running the trans in M5 for now though.

What are you calling "not normal" V4 vibration?

 

[iamdub]

Will the use of the Range AFM disabler affect my BB tune?

I'm not sure what the Range does to disable the AFM, so I can't say for sure. My guess is that it's work with it just fine. But that's a guess.

 

[iamdub]

Even using Synth only you gotta clean out the engine? I like the concept of the AFM, and I just went through a major overhaul replacing my camshaft and all the lifters and trays - a gift from the previous owner. I had been using standard 5w30 per the manual, but the guy that did my costly, timely rebuild said to always use synthetic and never use detergents.

I don't think I want to disable my AFM if I can keep the system working well. But I don't want to spend another $5K on an engine overhaul in the future. Is there any other preventative maintenance or should I go ahead and hit the delete button? AND - Can I even delete/disable/remove the AFM if I have a Hybrid? Is it integral to the Hybrid control system?

So, AFM failures have cost you thousands of dollars, but the AFM system operating has or will save you a few hundred dollars in fuel over your ownership of your vehicle?

 

[Lightning 95]

What are you calling "not normal" V4 vibration?

I guess I don't know what is normal. It feels like a rumble like driving on a rough surface. It is more annoying than anything, although I like saving fuel. If your supposed to be able to feel it I can learn to deal with it, but if it is an issue I need to get it addressed before my warranty expires.

 

[iamdub]

I guess I don't know what is normal. It feels like a rumble like driving on a rough surface. It is more annoying than anything, although I like saving fuel. If your supposed to be able to feel it I can learn to deal with it, but if it is an issue I need to get it addressed before my warranty expires.

I'd say the vibration when going slow in V4 mode feels and sounds like a rumble. It's probably a failed motor mount or both mounts. They leak their fluid out and the mount collapses, causing you to feel the vibes.

Unless almost all of your driving is cruising steadily at speeds under 70, you're not really gonna gain much from AFM, maybe 1-2 MPG max. That's pennies when compared to the cost of replacing the lifters and possibly cam and possibly even the whole motor when an AFM lifter fails. Check your mounts and replace them if necessary and disable (handheld tuner or custom tune) or delete (remove the components and tune out) the AFM.

 

[tiktok4321]

So, AFM failures have cost you thousands of dollars, but the AFM system operating has or will save you a few hundred dollars in fuel over your ownership of your vehicle?

I will say that most likely the previous owners caused the issues through neglected maintenance. I have not seen where the hybrid model can function properly without the AFM. That is my question. And the follow-up is, if I can't disable out, what is the best possible preventive maintenance?

 

[iamdub]

I will say that most likely the previous owners caused the issues through neglected maintenance. I have not seen where the hybrid model can function properly without the AFM. That is my question. And the follow-up is, if I can't disable out, what is the best possible preventive maintenance?

I'm not familiar enough with the hybrid to know if it can work without the AFM. Sounds like it can't, and I'm sorry for this plight.

There really is no preventative maintenance other than normal maintenance. Since the AFM lifters are more sensitive to being clogged, the best you can do is keep the inside of the engine as clean as possible. Change your oil regularly/as needed using quality synthetic oils and filters, use top-tier gasoline, a good air filter, etc. Using additives to clean the engine such as the ones you pour in before an oil change and drive for X miles then drain can help. But, on an engine that already contains some sludge, the additive (detergents) can break the sludge/carbon loose and actually cause problems if chunks of the sludge get caught in the lifters. Since your engine has been worked on internally, I'd hope that it was cleaned decently enough that there aren't areas of buildup remaining, waiting to break loose and potentially cause a problem. If it's clean, keep it clean by running a quality cleaner somewhat regularly to prevent the buildup in the first place. Maybe run a bottle of cleaner before every or every other oil change.

 

[tiktok4321]

I suppose that's the best I can do. Thanks for the info, and I hope I can get some good miles on this thing now.

Meanwhile, I'll have to drive 200,000 miles for the hybrid to pay for the gas...