2006 Envoy Displacement on Demand

[jp306972]

New member here

 

I have a 2006 GMC Envoy Denali 5.3L engine that has the displacement on demand system - switches off 4 cylinders under the right conditions to increase fuel economy. I bought it as a project vehicle, tuned it up, replaced the plugs and dumped the really nasty oil that was in it. The engine has 162,000 and clearly the previous owner didn't keep up on service but it is a very nice truck.

 

Usually I do my own work but with too many projects and too little time I decided to take it to a reputable mechanic. End result, we've determined that my number 4 cylinder has inoperable valves. They've tested the selenoids for the DOD system and found them to be operable. Futhermore, I had them pull the push rod to see if it was bent or scored, it was neither. The DOD system is throwing confusion into the diagnosis for me. The mechanic is recommending we pull the head.

 

Line of Questions #1

Is there something the mechanic may be missing with the DOD system that would get the valves working again. Can I go to non-DOD heads?

 

Line of Questions #2

If I go with a new engine, can I get something with additional performance that doesn't have DOD? Will the computer only take a DOD engine? If so can the computer be switched so I can use any LSx engine?

 

Retaining the 8% gain in fuel economy that Displacement on Demand gets me doesn't seem worth the limitation of choices in heads/engines.

 

Please Help

 

James

Moore, Oklahoma

[Chris]

Stay with a gen 4 engine. So any truck vortec 5.3/6.0/6.2 or LS2 or LS3. The computer will have to be retuned. A tuner such as Black Bear can do this. If you come across a bortec 6.0 such as the L76 it has AFM as do the truck 5.3's. It can be tuned out.

 

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[Duelin]

Usually when you have one cyl. where the a valve won't operate it is a collapsed or frozen lifter. When this happens GM recommends replacing all lifters and the AFM manifold (center plate). If so compare the cost of the repair against another engine.

[jp306972]

Thanks for helping the noob!

 

I feel like a kid in a candy store just knowing I have choices. I have a line on a gen 3 LS1 5.7 liter but that sounds like too much work - old wiring vs. 2006 cableless intake and chawkins6789 recommends gen 4 engines. I also found a cable intake 2004 GTO engine for $3500 with transmission. I don't know if I could use the transmission. My 2006 Envoy Denali is 4wd. The simplest choice seems to be a low-miles Cadillac Escalade 6.0 LQ9 at a junk-yard in Dallas.

 

$2900 5.7 LS1 and trans (surely this trans doesn't fit)

$3500 6.0 GTO engine and transmission

$2000 6.0 Caddy LQ9 engine (heavier then the GTO)

 

I will keep looking. And I want to call these Black Bear Performance people for advice on what is easiest.

 

Thanks Again

James in Moore, Oklahoma

[Chris]

You will have to go Gen 4. The Gen 3 will be a pain. Different plugs and locations of things changed.

 

As for Black Bear performance, they do business through Email

 

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Edited August 15, 2013 by chawkins6789

[jp306972]

Gentlemen

 

Do all Gen IV engines have the 58 tooth reluctor wheel for the crank sensor? I wouldn't want to mess with an engine that I would have to change from the 24 tooth reluctor to the 58 tooth, that seems like too much effort. I guess one removes the crank to replace the reluctor wheel. It migh also be harder to get the computer to work. I would simply like to flash the existing computer with a re-tune and remove the Displacement on Demand or Active Fuel Management stuff.

 

The salvage yard exchange lists this engine as 2006 only but for instance a 2007 silverado has DoD/AFM and looks identical from the exterior. The 2008 LS3 6.2 I'm looking at probably has a 58 tooth but I don't know how to check this. How do I know which engines have the 58 tooth reluctor?

 

The old engine will be out today. So I need to make a decision on its replacement.

JP

[BIGcraig]

   Ok, I am currently going thru this exact engine swap. 2006 envoy denali w/5.3. There are are some options out there. My donor engine is out of an 08 silverado. So first, let me say that 05 & 06 SUVs are bastard years in the transition to the gen IV in that they are gen IVs but have the 24x crank reluctor and the 1x cam. You can tell this 24x vs 58x just by looking at the crank sensor...24x has a black sensor, 58x uses a grey sensor. Lingenfelter makes a signal conversion box (TRG-002) that turns the 58x signal to the 24x that your computer needs. It saves a lot of time and $ of having to tear your engine apart to swap crank reluctors and cam.

 

    Besides that here is what I have ran into...I am pretty sure this will be the same on any gen IV engine unless you happen to find a good engine out of another envoy denali....first obviously, since the front drive shaft goes thru the oil pan, you will need to swap the pan and oil pick up tube over to the new engine. On my donor engine the dip stick tube goes thru the block above the oil pan and my oil pan's dipstick goes directly into the side of the pan. You need to use the right dipstick for the pan so I tapped the tube hole in the block and threaded a plug in to seal it.

 

   Next, you have to use the exhaust manifolds from the envoy denali. Truck manifolds will not work! I learned this the hard way! I didn't want to do the swap for fear of breaking a manifold bolt but ended up have to pull the again just to swap them over.  I am in the process of reinstalling the new engine and up to this point the only other issue that I've ran into is that my new engine had a bellhousing alignment pin on the passenger side and my trans has both alignment pins in it. Yes, I had to lift the engine back out to remove the pin from the block. A good sized hammer and a punch will do the job and its easier to do with the exhaust manifold off. 

 

     I realize this comes too late to help some of you guys but hopefully it saves someone the time and pain that it cost me to " learn as I go"!