2007 5.3 help needed

[Rizzle]

The 4cyl mode is not very active in those year trucks, as you may have noticed. I would say the best way for peace of mind in to do the LS7 lifter swap, ls valley cover, and ecu mod. Doubt you'll see more than 1mpg difference overall.

[jred]

not very happy with my 2012 gets like 14.5/15 around town and barely 20 on the road looking to sell mine and move to a 14 as the gas mileage is better, and comments would be appreciated

[wyrmrider]

just calculate if you will ever get a return on your investment based on your driving
with gas prices this low not spending capital is a no brainer- but how long will they stay this way

[69-CHVL]

Swapped out the lifters, cam, timing chain, water pump and just waiting for the ECM to come back from having the AFM disabled. I have about 1000.00 in parts (includes a new $200.00 GM water pump) and about 25 hrs of labor in this sucker!!!!

[69-CHVL]

Update - engine runs perfect now with the new cam/lifters etc. MPG doesn't seem to be affected all that much. But I gotta tell you I dont know if I could do that job for a living lol - took alot out of me leaning over that engine bay for a couple of days.

I cant help but wonder if this was the root cause of the failure. This sealing area was damaged. Not sure if it tore when the engine was disassembled or
tore during operation when led to the lifter collapsed.

[A_VAS]

revive old thread...I have an 09 Yukon with 6.0L and appears similar AFM issues...I'm not getting the misfire codes though.
I'm pulling the Valley cover first, and inspecting the sealing...thanks for the pic

I have a new valley cover (the 'updated' one) and the screen filter that comes with. Hoping to not have to pull heads and do the lifters.
truck behaves normal until you run for about 2+ hours, the oil pressure will slowly start to drop. It doesn't clatter or sound like the lifter is stuck, but I'm not sure. Would the lifter being stuck collapsed cause oil pressure bleed down? It drops down to like 10 psi when this occurs.

After the valley cover, my next step will be front cover and see if the oil pump o-ring is possibly shot or damaged. What I don't get is how it can run just fine on pressure for long periods, then all of sudden drop. If you pull over, shut off the engine, turn back on - pressure returns to 40+psi. Drive for 15-20min and it slowly bleeds back down.

[CGT]

revive old thread...I have an 09 Yukon with 6.0L and appears similar AFM issues...I'm not getting the misfire codes though.
I'm pulling the Valley cover first, and inspecting the sealing...thanks for the pic

I have a new valley cover (the 'updated' one) and the screen filter that comes with. Hoping to not have to pull heads and do the lifters.
truck behaves normal until you run for about 2+ hours, the oil pressure will slowly start to drop. It doesn't clatter or sound like the lifter is stuck, but I'm not sure. Would the lifter being stuck collapsed cause oil pressure bleed down? It drops down to like 10 psi when this occurs.

After the valley cover, my next step will be front cover and see if the oil pump o-ring is possibly shot or damaged. What I don't get is how it can run just fine on pressure for long periods, then all of sudden drop. If you pull over, shut off the engine, turn back on - pressure returns to 40+psi. Drive for 15-20min and it slowly bleeds back down.

I would look at the oil pressure relief valve in the pan, and or oil pump. 12608835 Valve, 12612289 Oil pump, 12639759 Deflector while your in there. 12584922 Pickup tube oring.

[woody b]

revive old thread...I have an 09 Yukon with 6.0L and appears similar AFM issues...I'm not getting the misfire codes though.
I'm pulling the Valley cover first, and inspecting the sealing...thanks for the pic

I have a new valley cover (the 'updated' one) and the screen filter that comes with. Hoping to not have to pull heads and do the lifters.
truck behaves normal until you run for about 2+ hours, the oil pressure will slowly start to drop. It doesn't clatter or sound like the lifter is stuck, but I'm not sure. Would the lifter being stuck collapsed cause oil pressure bleed down? It drops down to like 10 psi when this occurs.

After the valley cover, my next step will be front cover and see if the oil pump o-ring is possibly shot or damaged. What I don't get is how it can run just fine on pressure for long periods, then all of sudden drop. If you pull over, shut off the engine, turn back on - pressure returns to 40+psi. Drive for 15-20min and it slowly bleeds back down.

Your oil pressure problem is more than likely the screen right below the sender. If that's the case the only symptom is a low oil pressure reading.

[A_VAS]

thanks for the replies.

I changed out the VLOM which came with a new screen in there below the sender yesterday.
the ones I removed didn't have any real obvious defects...the screen has some trash (small particles) that may have restricted it.
I may have spent money on the VLOM unnecessarily...the screen is a $4 part. Oh well I pulled the intake to do it anyway, cleaned all the oil out of the intake manifold.

the sealing areas are all in tact, but they seem pretty squished down, the glands/o-ring areas might have taken a set and aren't sealing anymore. But there were no tears or damage/ blown out areas.

I have a pump and o-ring, going to change next week. Driving it today, the pressure is steady above 40psi hot...but I only driving 40 minutes at a time. This issue didn't show up previously unless I drove it 2+ hours.

[A_VAS]

I bought the truck w/ 90K on it, not sure how well maintained it was previous for oil changes.
I have been running synthetic, changing every 6K...now has 140K on it.

woody b:
this screen is actually filtering flow to the VLOM and the solenoids correct? So if the sender is reading low pressure, the VLOM is getting low pressure.., but the lifter galleys/bottom end/ etc are not being starved?

what was happening while driving it, is the pressure would start to drop on the dash gage...then check engine light would come on temporary...and the V4 mode seemed like it was locked out (stayed in V8 mode continuous). I'm thinking once the computer sees the low pressure, it disables AFM since it believes the pressure is too low to activate the lifter mechanism...
I'm hoping the rest of the engine had good pressure, it's just the sender being at the top of the flow path is getting a low reading due to blockage.
I guess I'm questioning if any damage was done ....while driving it with the "turn off engine now" message on LOL

[CGT]

I bought the truck w/ 90K on it, not sure how well maintained it was previous for oil changes.
I have been running synthetic, changing every 6K...now has 140K on it.

woody b:
this screen is actually filtering flow to the VLOM and the solenoids correct? So if the sender is reading low pressure, the VLOM is getting low pressure.., but the lifter galleys/bottom end/ etc are not being starved?

what was happening while driving it, is the pressure would start to drop on the dash gage...then check engine light would come on temporary...and the V4 mode seemed like it was locked out (stayed in V8 mode continuous). I'm thinking once the computer sees the low pressure, it disables AFM since it believes the pressure is too low to activate the lifter mechanism...
I'm hoping the rest of the engine had good pressure, it's just the sender being at the top of the flow path is getting a low reading due to blockage.
I guess I'm questioning if any damage was done ....while driving it with the "turn off engine now" message on LOL

We have actually had one with that message that we put all those parts in. VLOM, sensor, valve, oil pump, cam bearings, and rod and main bearings, still wouldn't make enough pressure to consistently keep that light off.

The customer traded it in because of it, we fixed it with an aftermarket high pressure melling pump and put it back out on the lot. Myself personally, I would want all the DOD stuff gone, there doesn't seem to be any savings when figuring in the trouble, although from your pics it doesn't appear yours was maintained all that well.

[A_VAS]

I agree...I would love to get the lifters out of there and put a LS3 cam in for instance.
however, this is a hybrid (LFA) and the passenger side, head removal looks damn near impossible. There's a large electrical box with large cables running down that side so I'm not sure I can get the head off without relocating a bunch of that stuff. I cringe looking at it.

I may do the HV pump when I pull the front cover, but was planning to do the melling 295 std pump. Do the engines with the oil pressure relief valve in the pan, signify when to use the HV pump ?
thanks

[CGT]

I agree...I would love to get the lifters out of there and put a LS3 cam in for instance.
however, this is a hybrid (LFA) and the passenger side, head removal looks damn near impossible. There's a large electrical box with large cables running down that side so I'm not sure I can get the head off without relocating a bunch of that stuff. I cringe looking at it.

I may do the HV pump when I pull the front cover, but was planning to do the melling 295 std pump. Do the engines with the oil pressure relief valve in the pan, signify when to use the HV pump ?
thanks

Not necessarily, the relief valve is even in the non DOD pans. If I have a pan off a non-dod vehicle, I will plug that hole. They sometime will have a little more pressure that way. I believe the valve is designed to blow off at 50psi, to "protect" the VLOM circuitry from what I've read, but if they fail, then who knows. But yes, all the DOD equipped vehicles are originally equipped with a slightly larger oil pump from GM. #12612289 VS #12678151 for non-dod

[In-Tech]

My research has shown than the cam must be replaced if using non-afm lifters, which kinda sucks but whatever. Sure beats having to replace an engine like I was initially thinking!!!!!! (I hope lol).

cam does not need replaced no....you can run AFM or non AFM lifters on that cam.

but if you are keeping the cam, and putting new AFM lifters in...might as well keep it active...for better mpg anyway.

The lobes for the AFM lifters have a different profile than the lobes for the non-AFM lifters. Two different lobe profiles on the same (AFM) cam.
Will it run with non-AFM lifters on the AFM lobes? Sure it will, but how well?

Ken

it will run the same as if it had AFM lifters in it, when the AFM is not active
doesn't make sense IMO to do this...since you will have to still turn off the AFM in the computer, change lifter guide trays, and will have a cam that is limiting power

I guess if you were trying to cobble something together with free parts you had laying around, it could make sense.

Sooooo, I hope you guys don't mind I revived this again.

I am with A_VAS in the thought that you should be able to put regular lifters on an AFM camshaft and just turn the crap off in the computer. Kenova posted that the cam has a different profile on those cylinders.

That makes no sense to me but I have never even cared to look at an AFM camshaft.

Here is my dilemma now...The machine shops around me call for tuning on occasion and I have plenty of AFM delete's in my pocket. I did a delete a few days ago and it had misfires on THOSE cylinders. Hmmmmm, that's weird. Misfires go away ~1300 rpm so I just set misfire information to not report till above 1600 rpm. Problem gone but I am very curious and since my rotary encoder has failed I am wondering if any of you have physically measured what is different on the Active Fuel Management cams? I find it unlikely those EXACT cylinders have some kind of base circle runout thing going on, but who knows.