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AFM/DOD question

5K views 7 replies 6 participants last post by  rcott01 
#1 ·
So my envoy is at around 106k. Still has plenty of power, rides and drives great. I noticed that when I am driving on highway the DOD kicks into 4cyl bc I hear the ton change and if I accelerate I hear the tons change back.

My question is when I am coasting after accelerating anywhere between 10-25 shortly after pedal isn’t pressed for gas it starts to tick repeatedly. At first I thought it was an exhaust leak but realized it want. I read on here that it doesn’t enable DOD when in 3rd fear so while it was doing it I shifted from d to 3 and it went away and never happened again.

It doesn’t tick at idle like a collapsed stuck lifter, is there anything I can do on the cheap side first to test other than drive on 3 locally lol? I know you can program out DOD but I’d hate to cause future issues since I know the DOD pistons have special lifters and the cam is not a standard cam. I consider my self slightly more mechanical than not but far from an expert mechanic.

My envoy is first experience with DOD so I don’t know too much just on the mechanics of it with different lifters the VLoM, etc. honestly don’t care for it that much, if I wanted better mpg I would have gotten a small suv with a 4 banger lol.
Has anyone tuned it out without issues? Has anyone fixed it without disabling dod or changing out lifters etc?

Any info would be greatly appreciated
 
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#4 ·
You can have it disabled in the tune , but eventually the lifters will fail and cause big issues. I bought a Saab 97x with the 5.3 really cheap because the lifters failed causing oil starvation and spun 2 rod bearings. If you are mechanically inclined and can do a cam swap, I would swap the cam, lifters, and valley cover. They sell dod delete kits but they are expensive. You can get a set of ls7 lifters for $100, gen 4 4.8 valley cover for $30 and a used stock 5.3 cam for $75. If you look around you might be able to find a deal like I got....ls2 cam, lifters, valve springs and keepers, pushrods, and ls2 valley cover from a 06 gto with 30,000 miles for $140....and a little bump in power.
 
#5 ·
Did you need to have it tuned with the ls2 cam? Is the power increase noticeable? I’ve been wanting to swap the cam in my gto for a while now I can kill two birds with one stone although I would like something a little rowdier in the Envoy if I’m gonna do all that work decisions decisions lol
 
#6 ·
I would assume you would tune it for the ls2 cam because if your getting rid of afm/dod you have to have that tuned out so might as well tune for the bigger cam too. Im in the same situation. I have 143,000 on my denali and i know eventually the dod lifters are going to be a problem. But at this point im going to wait for it to fail then deal with it then.


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#7 ·
My DOD wasn't active so I didn't have to get it tuned but I did. The guy who tuned it said that since the ls2 wasn't very radical that I would have been fine, but I wanted the speed limiter turned off and transmission tweaked. I did notice a pretty big gain in power across all rpms. I wanted a bigger cam, but didn't have a lot of cash at that time and needed to get it put back together quick. I found it lightly used and cheap that's why I ran the ls2. But I am very happy with it. I sounds stock, has a bump in power, and I average 18mpg around town when temperatures are above 35 degrees.
 
#8 ·
If it were mine I would remove the DOD hardware before it fails. Because when it does fail, a lot of times the crank and rods get chewed up or a rod gets thrown through the side of the block. Mine had 2 rods that spun the bearings and chewed about 3/8" out of the crank.....I replaced the whole engine. At the junkyard I go to i see a lot of the lh6 with a rod through the side of the block. Imo if you want to keep an aluminum block in it, fix it before it breaks.
 
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