DOD killing my L76 2008 Vortec Max – Help!

F1CAM · June 6, 2012

DOD killing my Vortec Max – Help!

Hello All,

Well my personal ride has developed a most irritating situation.. I have the L76 motor in my truck with DOD. I had a #4 intake lifter lock in the down position causing a P304 misfire code… (no valve train noise at all) I pulled the head off, changed all 4 of those AMF lifters back to new original DOD ones and Truck ran perfect and even more quite than it ever has.. This lasted for 2 days… Then the truck started acting up again when dod was kicking in (coasting off highway) and eventually locked the same dam #4 intake lifter down again..(now had valve train noise, took pushrod out and was quiet) I was beside myself, consulted with a local dealer (which was very helpful) and determined that I most likely was the VLOM solenoid that may be the problem.. Ordered a new VLOM assembly and put it in but it never unlocked that lifter.. So I am back to square one.. Thankfully I do my own work and am not getting killed on the labor but still hurting in the pocket.. Talked more about the situation with the shop foreman at Chevy to see if he ever had this situation.. He said NO and determined (best guestimate) that the Cam may be worn just enough on that lobe to not allow the instant transfer of the Lock and Unlock of the lifter causing a delay and keeping lifter locked.. Didn’t make to much sense…Or I would have had to do the VLOM first and then the lifter.. I did the reverse. What could be the cause for this to re-occur?

What are the odds now that I fix that one lifter again and it won’t lock up.. To do a cam swap is a lot more work and Money. I am looking for the easiest and cheapest fix right now.. I was thinking of just doing the one lifter again and unplugging the dod harness , what will happen if I do that? I can’t afford a programmer right now

Truck has 142k highway miles with NO mods at all – not even a K&N.. Always maintained and not abused. Inside motor looks nice and clean.

I was wondering to go with a DOD delete kit and if I go that route I will also need a Cam – Either a Stock “take out” or a slightly better one.. I just want reliable, I have my other cars to worry about going fast.. Also with those type of miles so I need to go in deeper while I was in there to change the Oil Pump and timing chain?

Can you Help me with any Budget Sensitive recommendations?? I am assuming if I go with a DOD delete kit I will need to redo my computer or get some type of programmer?? I almost thought since I have a NEW VLOM maybe I should just go back to all stock and try to find someone (you?) who has a takeout set of lifters and cam.. Can all 1 bolt cams use the VVT system like I have? I know the G8 doesn’t have it. I am very familiar with LS1 motors but never had a "VVT" cam experience...

Can I use a takeout or new L99 Camaro SS Cam that has VVT and DOD? GM cams can be bought for about $100 . If I had to do a cam swap also is that any better of an option.. There are a lot of people with new Camaros that take out the DOD stuff to upgrade and don’t know which route to take..

Sorry for rambling on but I am very frustrated and broke I have $800 in parts in it now and no change.… Thanks again for your time and I look forward to your response..

Dave

772-284-1169

[email protected]

jaredlucky16 · June 15, 2012

Clogged cat sounds correct

F1CAM · June 12, 2012

Got her back together... Guess what? If you unplug the harness to the VLOM it sends the PCM to Limp mode... Great.. Will driving around in 3rd keep the V4 mode off untill I get a tune or programmer? Other than that I am running on all 8 again!

Thanks,

8.1HD/ALLISON · June 12, 2012

Hmmm. Didn't think about limp mode.. I'm not sure if driving in 3rd will keep v4 mode off?

markw8 · June 16, 2012

Try NAPA. They were 1/2 the cost on my 2000, 6.0.

Mark

F1CAM · June 6, 2012

I forgot to add after I swapped the VLOM I bench tested the solenoids by appling 12 volt and ground to the electric connector at each one and they all clicked.. Not sure if it is an accurate way to tell proper funuction but usually testing solenoid this way tells the story.. I have seen TSB's that there are specific GM tools and process to do this as well. I just took the old school approach.. So I am assuming that there was nothing wrong with the VLOM and it just took a nice chunk out of my wallet and Friday evening.

Thanks, Dave

00Silverado4x4 · June 6, 2012

Can you just get the system "tuned" out so you won't have to pay out for all these additional parts. Also I know it's a lot of work/money I'd get that cam at least inspected to ensure that isn't one of the problems.

F1CAM · June 13, 2012

Welll after test driving the truck has NO power and pulling a P0300 Code.... I am at the end of my rope... This is with everything plugged in... Sound normal at Idle..

Daryl Z71 · June 6, 2012

Id put a set of LS7 lifters in it, tune the AFM out and be done with it. What a stupid design...

F1CAM · June 14, 2012

Broke down and took her in to the Dealership... Just got word that the right side cat is clogged now causing my problems.. I did drive the truck for about 3 weeks fireing on less than 8 cylinders cause I had to.. They were 100% sure that was the issue now because they put a pressure tester in the O2 sensor hole to determine it. Does that sound right? They also wanted $1200 to put a new y-pipe in.

F1CAM · June 6, 2012

Id put a set of LS7 lifters in it, tune the AFM out and be done with it. What a stupid design...

Can I do that and leave the VLOM and stock DOD cam in? Then get a programmer? If I go that route can I just leave the VLOM disconected until I get a Programmer?

Thanks for your Help!

00Silverado4x4 · June 14, 2012

$1200? Wow, that is a bite in the wallet, they can't replace just the cat?

F1CAM · June 14, 2012

No said they dont make an aftermarket one with the proper dimensions they can weld in. Its very tight in there not like previous years or the Left side, just my luck..

00Silverado4x4 · June 14, 2012

Sorry to hear it. I'd still go to a local exhaust shop to get a second opinion on that price. Might get lucky.

SouthCo · June 6, 2012

I may be off from what your asking, but many people with the AFM or DOD get a tune, like black bear or diablo something, and turn the AFM or DOD function off. They don't unplug, swap or change anything else and the AFM or DOD is disabled.

If I keep mine long enough, I plan to go that route.

F1CAM · June 15, 2012

Final Update... I Hope... The right side Cat was melted (side I had the lifter go bad twice) and the Left cat was starting to clog. I guess the cats didnt like driving on 7 cylinders for 3 weeks... I dont know if I will ever get to to bottom of why the #4 DOD intake lifter locked down and stayed down twice but as of now I got a Diablo Predator and programmed the DOD/AMF OFF.. Everything seems good to go.

Thanks for all your input..

Dave