Over the course of a busy 3 weeks, I've changed out the exhaust manifold which seemed to quiet down some of the noise, ran some BG EPR for 20 min in the crankcase, last tank had a bottle of Techron concentrate while awaiting my Amsoil Pi, and this tank has a bottle of Amsoil Pi.
I ran the EPR with the Pennzoil Platinum which had a bout 800 miles on the oil...I didn't want to wait to run the cleaner in case I had any build up in the ring packs, so I did lose out on some miles on the oil but I need to get this all figured out.
I received a better remote camera today than the one I had been using and will get some pics inside the cylinders. I was starting to lean on the possibility of some carbon knock since I did have that restricted PCV system for awhile, still unsure of what the chambers look like.
The motor runs very well after the exhaust manifold change. I cannot remember the last time I ever had 300 miles to the fuel light with my mix of 70/30 hwy/cty miles....averaging 18 MPG mixed, I believe I stated 18.5 in another thread but it was right about 18.2.
My last tank incorporated the 20 min BG EPR cleaning and 10 min of GM upper engine cleaner so the mileage at the fuel light was 292...both times the tank took 16.5 gal...so I'm stoked about that but hoping I don't need to really tear into this motor now.
After the new lash adjusters, manifold, cleaning chemicals, I have no cold start ticking...which happened after the replacement of all 24, but there's one noise that is starting to lead me to either a rod, possibly #2, and/or the skirt wear which could be some piston slap.
After returning home tonight, I took a quick video of the area around the AC compressor....not that the compressor is the culprit, but when the compressor engaged, the sharp knock seemed to quiet down considerably, but when not engaged, you could hear the knock.
Video taken tonight, you can hear the sharper knock behind the injector noise when the compressor kicks off.
This knock has me leaning me towards a
possible rod bearing because if I disconnect the coil to cyl #2, that's the only cylinder that almost completely reduces the noise. If I look around the top of the motor, I tent to fixate around that area as well.
The knocking sound that remains when hot, doesn't start making itself known until about 3 min into the warmup, but remains. This noise is at cam speed so perhaps not a carbon buildup near the crown or in the squish area. I was thinking maybe one side of the chamber had a deposit and would cant the piston slightly causing a tap where the opposite side skirt would hit the bore....but I don't believe it would happen at cam speed, but every rotation.
After hearing this noise over the last week or so, it actually is audible from behind the glove box area inside the cabin, almost mimicks an exhaust leak...but I did check all the bolts. The noise seems sharper on the top, and more dull on the bottom. I did get a video but after listening on headphones and the speakers, the camera mic seems to exaggerate the noise a little so when I get the video posted, please note that it's not as loud and defined as it sounds but it's still clearly audible when next to the vehicle.
The noise is also more noticeable standing near the RR door than in front or next to the RR wheel opening.
Sorry for the delay on the other video, but I will have it up soon.