NEED HELP Engine Knock and Running Rich

[Reed]

Hey guys. I just finished doing a total engine overhaul on my 2003 Trailblazer EXT, including new timing kit, water pump, serpentine belt, thermostat, fan clutch, ignition switch, and muffler/resonator (but no new catalytic converter). Took it for a test drive, and it was running good, but after driving it for approximately 12 miles, the engine started knocking, so I parked it overnight. The next morning, I checked the oil and started it. It was running very RICH, even blowing soot from the exhaust. Code 0340 (over advance timing). I tested the camshaft position sensor, and it was in spec. Reset the codes, and started the engine again and got a check engine light. OBD code now showing P0014. I pulled the camshaft actuator. The screens were intact and still clean. I cleaned it anyway, and back probed the wiring to test the signal. Checked out good, although the connector end spun on the solenoid. I disconnected the battery to reset codes, and reconnected. Started the engine again and still got excessive fuel mix from exhaust (moisture with black soot), and engine knock. CEL on, but showing NO CODES.
Although the sensor and solenoid tested good, I replaced both of them. The new fan clutch runs 100% of the time, and has since I installed the new one. The engine knock is still pretty constant, although it goes away, shortly, at times while at idle, and I'm still getting soot from the exhaust.
Any ideas on where to go next? Is there a way to test the Dephi camshaft actuator? Could it be a bad oil pressure sensor, or a bad crankshaft position sensor?
Thank you!

 

[Mooseman]

Where does the knocking seem to come from? On top of deep down? Any way you could record a video of it and post a link?

 

[mrrsm]

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[Reed]

Thanks for replying Mooseman.
Nothing changed, as far as the knocking, when I performed a cylinder drop test. I traced the knocking down, and it seems to be coming from the torque converter. Occasional knock at idle while in Park, and a definite knock and rough idle while in gear, with brake applied. I'm not a transmission guy, so I don't know if it is due to a loose bolt(s), or the TC is bad? I will try to get a video posted with sound.
However, I still have soot mixed with condensation coming from the exhaust, the engine runs rough when in gear, and I'm showing NO oil pressure on the instrument panel now, but the oil level is full. The instrument panel oil gauge shows pressure when then sensor connector is disconnected! I haven't had a chance to test the oil pressure at the sensor port yet.
Although the cam position sensor needs oil pressure to operate properly, wouldn't the engine shut down if there was no oil pressure?
My engine still has the first generation oil pump and cover, however, I cleaned the pump, and checked the tolerances of the pump during the overhaul, and they were good.
The "Check Gauges" light is on, and the "Service Engine Soon" light is off, but there are no gauges illuminated, other than the ABS, Brake, and Airbag lights. But they have been on prior to the rebuild. The ABS/Brake lights are on sporadically, even though I cleaned the sensors, and replaced the ignition switch. The Airbag light stays on constantly. I believe from a bad sensor, not a connector or ground.
Even though the "Check Gauges" light is on, no DTC codes are showing up.

 

[BlazingTrails]

Unfortunately... There have been some instances... especially involving actual GM Engine Technicians installing the VVT Phaser/Actuator and Timing Chain Set and not have the Exhaust Cam Phaser correctly rotated slightly clockwise prior to the two-step Tightening/Torque and TTY wind in of the Hex Center Bolt. This mistake was causing the Internal Stop Tab designed to keep the device from exceeding its restriction of only 25 Degrees of permissible rotation... to snap off.... rendering the VVT Exhaust Cam Phaser on the sprocket... useless. Quoted from the below listed comprehensive GM Atlas Engine White Paper:

"Note: The exhaust cam phaser must be at the fully advanced position."

http://vortec4200.com/index_htm_files/vortec4200.pdf

And after all that "High Brow" Look-See... HERE IS THE VERY STEP-BY-STEP BIBLE OF THIS REPAIR...WITH EXCELLENT IMAGES, TOO!:

http://ww2.justanswer.com/uploads/GMGreatWrench/2011-01-08_023933_tblazer_t-chain_part_12.pdf

Coincidentally...this affects the actual valve position in concert with the maintaining the relationship between the dark links (every 7th) and their correct placement on the Crankshaft/Gerotor Sprocket along with somehow getting the incorrect placement of the chain... even when the Engine was being serviced on an engine stand. Apparently... this is one of those weird events that prompted GM to publish the above listed "How-To" instructive PDF on the correct procedures to follow... with all the additional warnings that lead up to the problems happening in the first place. This below listed link has a very informative Tech Article that covers the subject from Soup to Nuts.. .and the last few paragraphs will describe what the Techs do to avoid this problem... with the mention of the "Private" ACDelco version of how to work with the damned thing.

http://www.diagnosticnews.com/gms-variable-valve-timing/

This Delphi Document shows the diagram of the relationship between internals of the Exhaust Camshaft Phaser, The CPAS Oil Contol Solenoid and the CPS in action via the PCM and Variable Oil Pressure:

http://delphi.com/docs/default-source/old-delphi-files/1809472a-5a95-4e30-b795-d226111152b8-pdf

That's exactly what I was going to say only a little shorter. Good form

 

[mrrsm]

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[Reed]

Camshafts were installed with flat sides up, #1 TDC, actuator rotated completely clockwise with Delphi parallel to head, before installing timing chain. Overhauled on stand. Removed bolts from torque converter and dropped trany with TC in bell housing. Replaced ALL gaskets and seals, top and bottom, including 4WD disconnect. Reinstalled original flex plate after cleaning and inspection. Original starter. Refurbished the crankshaft. New oversize pistons/rings, main bearings, piston pins, and bolts torqued to specifications. No new rod bearings. Hand rotated engine during assembly, back to #1 TDC, but not since problem arose. Checked vacuum lines, and replaced the fuel pressure hose and dirty air hose. Oiled bottom end by hand during assy, and filled the filter before installing, but I did not add oil through the oil ports prior to start-up. Waited one day after filling engine with oil before starting.
Mine sounds like the 1st video (tensioner pulley) but I checked ALL pulleys, and I removed the serpentine belt and ran the engine with out any changes (ie: still knocking). It also sounds like the second video (VVT solenoid), but I have installed a new one, as well as the camshaft position sensor. Although I believe the knock is from the TC, it doesn't make the pinging sound like the one shown in the 3rd video. And, it resembles the knocking from the 4th video as well, but listening to my engine, the sound was not at the valve cover like his was.
It's looking more and more like I will have to pull everything again to replace the oil pump and front cover, and hopefully just have to re-torque the TC bolts without any further headache. I hope there's a better solution??? Pulling that engine and transmission is not my idea of a good time.

 

[Mooseman]

If noise is coming from the TC area, it could be a cracked flywheel. A few have been coming across here as of late.

http://www.gmtnation.com/forums/threads/ticking-sound-from-flexplate-torque-converter.14393/

 

[mrrsm]

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[mrrsm]

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[Reed]

OK guys. I finally got back to the TB. Found metal shavings on the oil plug. Pulled the engine, and broke it down. The problem was not the torque converter, the flywheel. the VVT actuator. or the harmonic balancer. It was a spun main bearing on #4. NRRSM. you asked about the crankshaft. It was polished, not turned. Used old crank shim between front cover and HB.
I'm guessing the bearing spun due to one of the following: I did NOT pull the fuel relay to prime the engine with oil. or prime the engine with oil through an oil gallery plug, or pack the oil pump gears with petroleum jelly. I will be replacing the oil pump, screen, and front cover to the 2nd generation pump. Replacing the main bearings, front and rear cover seals, and #4 connecting rod. And I will have the crankshaft polished again. Could polishing the crankshaft possibly require me to need oversize bearings? Should I wait to order the new bearings until it is polished?

 

[mrrsm]

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[Reed]

You guys are good. MRRSM, the bearing that spun is the #4 connecting rod, not the main bearing. Sorry, I gave the wrong information by saying it was a main bearing. I want to check the clearances on all of the remaining bearings, as well as the main bearings, to make sure they are within spec. I don't know if the machine shop took off too much material when they polished the crankshaft? Do any of you know what the clearance specifications are for the connecting rods/journals, as well as the main bearings/journals, for the 4.2L engine? I didn't see them in the manual.

 

[Mooseman]

Here are all the specs you would ever want.

 

[Reed]

The crankshaft and connecting rod both need to be replaced. as well as the oil pump, oil pick up tube, and timing cover. Cylinders are already oversized, and the they need to be honed to remove blemishes. The machine shop recommends I replace the engine.
Considering the costs for additional parts and labor, and the fact that this engine endured overheating, which caused the head gasket to fail initially, and the machinist recommends replacement; I am considering taking a loss on the parts already replaced on this engine, and purchasing a remanufactured engine instead of continuing down this path.
If I go with a remanufactured engine, would you recommend a newer model engine, in place of the 2003, or is that even possible? If it is possible to use a newer engine, would the PCM need to be flashed? If I stay with a '02-'04 engine, will the PCM need to be flashed anyway?

 

[mrrsm]

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