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GM 3.6 VVT

I don't know on that engine, but on the I-6 4.3 like in the ex's 05 Trailblazer, the VVT is oil pressure activated through a mechanical piston/solenoid that mounts at the front of the head behind the alt. The filter screens were known to plug up with the slightest bit of gunk in the oil past about 3,000 mile oil change interval. Updated P/N AC Delco/Delphi replacement and aftermarket replacements had much larger intake screen areas to maximize oil flow and minimize the screwed up valve timing.

Could part of your problem, looking at that nasty ass filter medium that's basically plugged solid (makes one wonder how many thousands of miles the bypass valve was open letting unfiltered oil pass throughout the engine, let alone when the last oil change was?) be that the valve timing is different on one bank of cylinders than the other due to a plugged/slow responding VVT actuator?
 
That filter media looked like it has some sparkly stuff on it, maybe it was the camera reflection. how is the oil pressure on first start up and after running a bit?

I have learned on some of the newer GM engines like in the trail blazers, tahoes, burbs, and many more that GM has a flaw where the oil pump is behind the timing cover and the o-ring that seals to the pickup tube cracks and starts sucking air, looses prime. prolonged use destroys the engine. I have seen several with this issue end up with spun bearings.
 
I'm thinking most of the stuff in the filter is from the cam chains and associated part and that the filter caught 99% of it being washed down into the pan and sucked back up by the oil pump. The oil pump is behind the chain but in the research I've done oil pump issues were never mentioned. I am planning on putting on a new pump "while I'm in there". I would like to check the oil pressure but don't know where to do so at this time
 
That's good. Looks like all the chunky, over 10 micron stuff was caught in the filter media. I still wonder (not knowing that engine, it's specifics, or known weaknesses) if really filthy oil may have affected the VVT actuation system and it creating some of the problems you're encountering. I know on the I-6 4.3 it caused power/acceleration issues, idling roughness/surging and would also set some sort of camshaft code sometimes, too.
 
I would think that with a V engine with VVT on each bank, that the valve timing being off between the two banks, and thus power, that with the firing order going back and forth between the banks you would get uneven power and hence vibrations that could feel/hear like "knocking". Just a theory, as I really have no experience whatsoever with that engine, just my experience with the VVT system on another GM system, the I-6 4.3.

As far as V-6 gassers, just the 3.9 in my daughter's 2002 Dakota Sport and the venerable 4.3 GM of the mid-80's to mid-90's I wrenched on.
 
It could. Or one of those sender sockets that has the cut out side in it to let the pigtail remain uncrushed while removing/installing? The one I have also has a hex on top of it, as well as a ½ drive recess, so you can either get on it with a ratchet/extension or with a combination wrench, depending on clearance issues. It works great on downstream O2 sensors that have the bung on top of the pipe and it's tight room between the sensor's top and the underside of the floor pan. Seems that 1¹/¹⁶ hex is some kind of standard across vehicle manufacturers and various sensors/senders.
 
Yup, I too have one of those deep well 1/2” drive sensor sockets with the cutout. I dont remember what vehicle I bought that for, must have been like You stated and for an O2 sensor. Those wires are auite some stiff.
 
the sender is metric odd thread too! I had finagled a hillbilly one some time ago for a 5.3l. used a 3/8" brass male flare. found that threadded in easily but the sender has a oring on it similar to a boss hyd fitting.
 
The 3.6 has 4 cam sensors and 4 VVT solenoids to control cam timing. Cam codes can set due to a bad solenoid, stuck VVT, Plugged oil passage, or low oil pressure. They can "Knock" if the conditions are right.

I would confirm oil pressure first. If that's good pull the valve covers and timing cover to inspect the timing chain tensioners. They are common to fail and cause the chain to loosen up and make noise.

Also running ATF in these for a few hours is a great way to clean out the oil passages.
 
Oil pressure cold and hot and then the codes. When it's all the way warmed up it has a pretty good knock, but I still don't think it sounds like a bottom end knock. Plus that was 5w20 oil (which is what I had) and it's supposed to have 5w30
 
Don't know what the OP specs are supposed to be for that motor, but your trouble codes definitely show there's something up with the valve timing, both intake and exhaust, with the beast. Very well could be a VVT actuator issue of a chain/guides issue, any/all of which are most likely related to the 'sludge in the filter, when was the oil last changed?' issue.
 
10psi is minimum oil specs on a 3.6. Looks like your a little on the low side but your running 5w20 so that might be why.

All 4 cams are throwing codes for position so I doubt it's an actuator issue. Its more than likely out of time mechanically. Can you read VVT data? That can be helpful to narrow it down. If its out of time constantly then I'd say it's a chain issue. If its fluctuations in and out then it might be a oil pressure issue on the upper end of the engine. The VVT system needs proper oil pressure to function properly. The Ford triton engines would knock like a SOB if you got the VVT to stick.
 
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