DOD delete but keep VVT?

[ckeister]

So it is looking more and more like the cam bearings are toast or got one starting to walk out in our 07 Denali. From my reasearch and understanding, our rig has all the DOD components but DOD is not tuned into the ECM. Not matter the end result whether we can just get away with replacing cam bearings, up to full rebuild, if it is the cam bearings, the DOD components are coming out.

We live in California so I don't think I can eliminate the VVT and still pass smog. Has anyone done a DOD delete but kept the VVT? If so would like to hear your experiences.

Thanks

 

[donjetman]

So it is looking more and more like the cam bearings are toast or got one starting to walk out in our 07 Denali. From my reasearch and understanding, our rig has all the DOD components but DOD is not tuned into the ECM. Not matter the end result whether we can just get away with replacing cam bearings, up to full rebuild, if it is the cam bearings, the DOD components are coming out.

We live in California so I don't think I can eliminate the VVT and still pass smog. Has anyone done a DOD delete but kept the VVT? If so would like to hear your experiences.

Thanks

So you have determined its an early L92? with smooth VLOM, etc.
Only the early production L92's had AFM hardware, built prior to April 1, 2006. These early L92s were built with AFM Hardware but the AFM system was disabled.

 

[Joseph Garcia]

I just had my cam and other motor parts replaced on my 2007 Yukon XL Denali, and my L92 did not have any AFM parts in it. I still went ahead and replaced the lifters.

 

[Marky Dissod]

So it is looking more and more like the cam bearings are toast or got one starting to walk out in our 07 Denali.
From my research and understanding, our rig has all the DOD components but DOD is not tuned into the ECM.
No matter the end result whether we can just get away with replacing cam bearings, up to full rebuild, if it is the cam bearings, the DOD components are coming out.

Engine Half@$$ subroutine was left UNenabled in the ecm. Engine Half@$$ hardware should come out, no matter what.

We live in California, so I don't think I can eliminate the VVT and still pass smog.

What's the reasoning behind this thought? Even if CA can visually detect that it was PHYSICALLY removed from the engine,
CA has no way of detecting whether or not the VVT subroutine has been disabled.
I've been over this many times: CA cannot download your tune off the ecm / tcm when they do an emissions test.
CA can only detect checksums and checksum verification numbers, both of which remain unchanged if the tune was written PROPERLY.

If, due to disabling VVT, the engine no longer passes a butt sniff test,
that in and of itself does not conclusively prove the VVT was disabled or deleted.

Has anyone done a DOD delete, but kept the VVT? If so would like to hear your experiences.

Although I haven't done it myself, it's easy enough to physically limit the VVT from INSIDE.
Obviously the tune would need to 'agree' with any hardware changes.
Sorry, no experience myself, but it's accepted that there are VVT cams that don't retard/advance as much as GM OE;
those cams need VVT limiting hardware to operate properly, and the tune needs its VVT subroutines edited accordingly.
So hardware that locks VVT in a fixed position, without removing VVT, would function the same as removing VVT,
if the VVT function were effectively disabled in the ecm as well.

 

[donjetman]

So you have determined its an early L92? with smooth VLOM, etc.
Only the early production L92's had AFM hardware, built prior to April 1, 2006. These early L92s were built with AFM Hardware but the AFM system was disabled.

how many miles on your ole lifters?

 

[ckeister]

So you have determined its an early L92? with smooth VLOM, etc.
Only the early production L92's had AFM hardware, built prior to April 1, 2006. These early L92s were built with AFM Hardware but the AFM system was disabled.

Vlom is not flat, has the raised vein looking things so DOD soleniods are there. Production date sticker is worn off so dont know production date. My understanding is DOD not in the tune of 2007 model year. Never driven a dod vehicle but i would imagine I would be able to tell if it had.

 

[ckeister]

Engine Half@$$ subroutine was left UNenabled in the ecm. Engine Half@$$ hardware should come out, no matter what.

What's the reasoning behind this thought? Even if CA can visually detect that it was PHYSICALLY removed from the engine,
CA has no way of detecting whether or not the VVT subroutine has been disabled.
I've been over this many times: CA cannot download your tune off the ecm / tcm when they do an emissions test.
CA can only detect checksums and checksum verification numbers, both of which remain unchanged if the tune was written PROPERLY.

If, due to disabling VVT, the engine no longer passes a butt sniff test,
that in and of itself does not conclusively prove the VVT was disabled or deleted.

Although I haven't done it myself, it's easy enough to physically limit the VVT from INSIDE.
Obviously the tune would need to 'agree' with any hardware changes.
Sorry, no experience myself, but it's accepted that there are VVT cams that don't retard/advance as much as GM OE;
those cams need VVT limiting hardware to operate properly, and the tune needs its VVT subroutines edited accordingly.
So hardware that locks VVT in a fixed position, without removing VVT, would function the same as removing VVT,
if the VVT function were effectively disabled in the ecm as well.

You know more than i about the subject. We have an unbelievable amount of shenannigans going on in our great state. We live in a county that only requires smog when you bring a new car into the county. Unfortunately, a new law has been passed banning these decisions by individual counties and a new state run smog program is supposed to take affect this year. Don't think they have their shit together to impliment it this year but we shall see.

As for keeping the VVT, I imagine it would help with the fuel mileage which aint great at 12MPG. I don't want to try and get to fancy with this as im still learning the platform so I am leaning toward just stock factory non DOD cam and lifters.

 

[donjetman]

Vlom is not flat, has the raised vein looking things so DOD soleniods are there. Production date sticker is worn off so dont know production date. My understanding is DOD not in the tune of 2007 model year. Never driven a dod vehicle but i would imagine I would be able to tell if it had.

Okay, getting rid of the hardware will increase the vehicle reliability

 

[ckeister]

how many miles on your ole lifters?

137K I don't have any ticking other than what sounds like injectors to me. Got a scan tool coming tomorrow so well see what the live data and cylinder balance looks like

 

[ckeister]

So here's how it has gone since purchase. After I noticed the oil pressure situation I did an immediate oil change with Amsoil 5-30 and Amsoil filter. Got a slight improvement. Didn't cut open the filter like a dummy. Put about 5K than another oil change. Stayed pretty consistent and like I said no alarms have gone off in the dash. Factory specs say idle oil pressure can be as low as 6 PSI which I think is ******** but.....

While doing routine stuff like changing belts hoses tentioners, fluid changes, etc. I found an old screen that goes under the pressure sender stuck between some shit in the engine compartment where someone dropped it so knew the sender had been changed at least once.

About this time last year, I broke my ankle real bad and was laid up for 12 weeks with another 12 weeks of PT. During that time, the ignition switch took a shit so I sent it to a mechanic and told him about the pressure issue. He changed the pressure switch again (put in a NAPA unit) and told me it was the o-ring and when you do that job ou just do the pump at the same time quoted me $2500. I asked him if he put a mechanical guage in to test actual pressure, nope just guessed and changed parts. Ok I'll pass and wait until I recover to do it myself, thanks.

Another 5K on the clock so went to do the job. Put a mechanical guage on the port comming off the oil pump. Never went below 37 PSI at the pump (Take note cuz this is the beginning of my head scratching) but had a consistent 15 PSI difference through out the RPM band. First big red flag.

Pulled the pan and has some metal shavings but nothing that was super obvious or concerning. Pulled a couple rod bearings, they looked good. Did a visual of the cam bearings and there was no obvious walk out on them. Should of cut the oil filter open I know but was wanting to get the job done. Replaced the pick up tube and O-ring with a Melling unit. The o-ring was **** eyed a little on the tube and flattened out a bit but not split. Slapped it back together, filled it up and ran it again.

Now here is where things start getting wierd. Picked up about 10 PSI on the cold start and about had a more consistent reading between the mechanical guage and the dash and hot idle went from 6-8 lbs up to 15-18lbs. Now the mechanical guage and dash were reading the same. What happened to my 37 lbs out of the pump at idle? Stuck relief valve in the pump im thinking.

Since I hadn't put the front differential back in, I went ahead and ordered a melling 365HV. Timing chain is nice and tight but while im here I said screw it and replaced the cam plate, VVT solenoid, timing chain tentioner, and couple other things that I know are prone to go out and much easier to change with the front diff out.

Back together it goes, and no improvement. In fact the 15 lbs of pressure variance came back abouve 2500 RPM but not improvement at idle 15-18. Additionally I have an intermittent fluttering on both guages (2nd big red flag)

Wife drives it to the store an back, maybe 20 miles round trip. Comes back and says the guage in the dash is back down to just above the red mark which was where it sat when it was running 6-8lbs. All that work FML....lol

So we go for a nice evening drive and put about 50 miles on it. The entire time I had at least 10LBS per 1000RPM throughout the the RPM range.....for the first part of the trip. On the way back home pressure keeps getting slightly worse,do a couple of hard accelerations and loose that 10 lbs per 1000 RPM at 3500-4000 RPM (Third big red flag).

Going up the mountain almost home and it starts losing power, less oil pressure to the point I get a check engine light 5 minutes from home. Once home and idling pressure is lower than ever even appearing to slightly go into the red, but again no dash warning. Plug the code reader and get p0011. Damn it.

Cleared the code and drove it around the next day about 10-15 miles code hasnt come back. I'm confident I didn't F anything up with the timing. Marks all lined up fine. I don't thing its the O-ring because I pulled the dipstick and no air bubbles on the stick.

So here is where I stand. I think either I have smoked cam bearing or one beginning to walk out or both. Only thing that makes sense in my head. No lifter noise, seems to run fine, and no misfire codes have popped up.

 

[Marky Dissod]

Get your used oil analyzed, preferably the most recently used motor oil.
They might be able to tell by what they find in it, which bearings (if any) are shedding / wearing down.
Have you yet done the
'add 2 extra quarts, point it steeply downhill, see if oil pressure improves' test?
Also, have you checked for coolant in the motor oil?
Not that I'm a downer, but being a pessimist often makes me a temporary downer -
until you rule out those two things.

You know more than i about the subject. We have an unbelievable amount of shenannigans going on in our great state.
We live in a county that only requires smog when you bring a new car into the county.
Unfortunately, a new law has been passed banning these decisions by individual counties and a new state run smog program is supposed to take effect this year.
Don't think they have their schidt together to implement it this year but we shall see.

As for keeping the VVT, I imagine it would help with the fuel mileage which aint great at 12MpG.
I don't want to try and get to fancy with this as im still learning the platform so I am leaning toward just stock factory non DOD cam and lifters.

VVT (actually it's variable CAM timing, but whatever), retards or advances the cam, depending on the desired load,
so it can run as much timing as reasonably possible.
If you're not upgrading to a cam that needs VVT either limited, or defeated, keep it.

 

[ckeister]

Get your used oil analyzed, preferably the most recently used motor oil.
They might be able to tell by what they find in it, which bearings (if any) are shedding / wearing down.
Have you yet done the
'add 2 extra quarts, point it steeply downhill, see if oil pressure improves' test?
Also, have you checked for coolant in the motor oil?
Not that I'm a downer, but being a pessimist often makes me a temporary downer -
until you rule out those two things.

VVT (actually it's variable CAM timing, but whatever), retards or advances the cam, depending on the desired load,
so it can run as much timing as reasonably possible.
If you're not upgrading to a cam that needs VVT either limited, or defeated, keep it.

That is part of my follow up plan. Im gonna keep driving it awhile maybe 1500 miles or so and send in an oil sample. I tossed the old oil in with the rest of my used stuff unfortunately. I was overly confident I was going to solve the issue. I have a scanner comming tomorrow so we'll see what the live data and cylinder balances tell us.

Did the overfill when I first got it and it went up but not much. I can try that again though i guess. just in case I did mess up the o-ring but I don't think I did. I know I have to do the o-ring on my truck but it gets better with heat, not worse.

 

[rdezs]

From reading what you posted, it sounds like you reused the o-ring? I hope not.... If you did, pull the pan and replace it. Look online for the oil pickup tube girdle that utilizes both threaded bolt holes in the oil pump to secure the pickup tube. While you have the pan off, plug the oil relief valve that is inside the pan. If you look online, there's several sources that have a bolt with a copper washer to replace it with. The melling pump should be just fine. Pull both heads and remove the lifters and trays. Replace with LS7 lifters..... Make sure they're genuine GM. Same for the lifter trays, genuine GM. Remove your vlom crap and the solenoids. Look online, several sources have plugs you can tap into the oil towers to plug them. Pick up a flat valley cover.... Several sources have them with the o-rings for additional insurance plugging off the towers. Pull out your camshaft, replace with an oem L92 camshaft. If the VVT solenoid that you used is not ACDelco or genuine GM, replace it with such. Have your heads checked for flatness. Replace that NAPA oil pressure sending unit with an AC Delco. Should be good to go, unless......

While you have your camshaft out, take a look at the cam bearings. The front ones always the worst. On Amazon you can pick up a handheld thing with the screen and about a 3-ft lead with a little fiber optic camera on the end. Very nice for getting a look at all the cam bearings. If they're toasted, you'll be pulling the engine to replace the cam bearings.

 

[ckeister]

From reading what you posted, it sounds like you reused the o-ring? I hope not.... If you did, pull the pan and replace it. Look online for the oil pickup tube girdle that utilizes both threaded bolt holes in the oil pump to secure the pickup tube. While you have the pan off, plug the oil relief valve that is inside the pan. If you look online, there's several sources that have a bolt with a copper washer to replace it with. The melling pump should be just fine. Pull both heads and remove the lifters and trays. Replace with LS7 lifters..... Make sure they're genuine GM. Same for the lifter trays, genuine GM. Remove your vlom crap and the solenoids. Look online, several sources have plugs you can tap into the oil towers to plug them. Pick up a flat valley cover.... Several sources have them with the o-rings for additional insurance plugging off the towers. Pull out your camshaft, replace with an oem L92 camshaft. If the VVT solenoid that you used is not ACDelco or genuine GM, replace it with such. Have your heads checked for flatness. Replace that NAPA oil pressure sending unit with an AC Delco. Should be good to go, unless......

While you have your camshaft out, take a look at the cam bearings. The front ones always the worst. On Amazon you can pick up a handheld thing with the screen and about a 3-ft lead with a little fiber optic camera on the end. Very nice for getting a look at all the cam bearings. If they're toasted, you'll be pulling the engine to replace the cam bearings.

Negative. New o-ring that came with the melling pick up tube. Put in the melling support on the o-ring bracket as well. VVT solenoid was also Melling and quite dissapointed when it said "made in China." I think the low oil pressure triggered the p0011 code not the solenoid but if I go in again I'll use the AC Delco. With that said, pretty much all the Delco stuff I have been ordering is Made in China so not sure it matters as much anymore.

Got a Scan Tool comming tomorrow. That and cutting into the oil filter I think is gonna confirm what I already suspect to be the case. Already sourcing a new bare block because with this and the rate of failures on the new 6.2 im reading about here and other places I do not trust a GM reman engine at this point and will be hitting up my old machinist from my racing days ad building it myself. Damn shame what GM has become.

 

[j91z28d1]

wow what a journey.

I missed if you still had bad oil pressure right now at the test port next to the pump with a mechanical gauge.

edit, yeah I believe there's a stock grind cam without afm but with VVT. part numbers In cam thread somewhere. that would seem to be the one for you if your not wanting to have the ecm tuned for a small aftermarket truck cam. they do pick up some power.

 

[petethepug]

It’s unlikely that you have a very early 07 with the inactive AFM hardware. Here’s the TSB to determine if you do …

https://static.nhtsa.gov/odi/tsbs/2020/MC-10180695-9999.pdf

If you end up wanting to go the reman route and the motor needs a refresh or rebuild, Jasper has turnkey engines to go from L94 (AFM) to L9H (Non AFM).

They may have a straight swap to go from an early AFM L92 to a Non AFM L92.

 

[ckeister]

wow what a journey.

I missed if you still had bad oil pressure right now at the test port next to the pump with a mechanical gauge.

edit, yeah I believe there's a stock grind cam without afm but with VVT. part numbers In cam thread somewhere. that would seem to be the one for you if your not wanting to have the ecm tuned for a small aftermarket truck cam. they do pick up some power.

15-19 at at the pump with mechanical guage right now. I'm assuming the pressure on the original test was gummed up oil filter (original test was old oil and filter with 5K) which is why I need to cut open the filter but I cant find my damn filter cutting tool!!!!

Is the cam grind different? I havnt gotten that far or are you talking the cam mounting bolts being different?

 

[j91z28d1]

15 to 19 hot idle but still dip in the red on the dash? that could be a few different things. you might move the mechanical gauge up to the sensor port. I'm 99% sure it's the same thread.


man these oil pressure threads are brutal. I've honestly never seen anyone post a solid fix. usually lots of parts replaced, going back in a 2nd or 3rd time for a high volume pump brings it up enough to be ok with it.


if you have a walking cam bearing. I'm pretty sure you can't change them in the truck. you need to pull the engine.

 

[donjetman]

This will keep ya busy:
https://www.onallcylinders.com/2019...de-to-ls-engine-specs-and-ls-engine-upgrades/

 

[j91z28d1]

15-19 at at the pump with mechanical guage right now. I'm assuming the pressure on the original test was gummed up oil filter (original test was old oil and filter with 5K) which is why I need to cut open the filter but I cant find my damn filter cutting tool!!!!

Is the cam grind different? I havnt gotten that far or are you talking the cam mounting bolts being different?

I've looked thru so many cam threads lol. but from memory, I think it was a slightly smaller grind. might have up a few hp as 6k and gain a few tq as 1500 rpm. but close enough I don't be tuning is required. they had the gm part numbers listed.

the front of the cam, I have no idea. I'd just guess it is since it's still vvt?