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OK, so here's the story...performed a relative compression test but during cranking heard an uneven cranking cadence so was thinking things weren't going to be good....scope was synched to #1 cylinder and found low compression on #8 cylinder...did a running "in cylinder" capture with the pressure transducer in # 8 cylinder and basically no compression of 1.57 psi...since there was a P0106 for MAP sensor “performance” and dealer said the MAP reading was "erratic" I was thinking this may be related to an intake valve possibly....removed the valve cover and quickly noticed a broken valve spring along with some roller rocker needle bearings present on # 8 intake valve...there is a TSB if any are found in the oil pan during an oil change...the diagnosis took less time then posting this...LOL !!…so no “dropped valve” or new engine that the dealer said this car needed…INCOMPETENCE !!
Relative Compression with Low Compression #8 Cylinder #1 Cylinder Sync Running Compression - 1.57 psi Piston Dome No Damage Observed Broken #8 Intake Valve Spring Needle Bearings TSB For Needle Bearings Found in Oil Pan during Oil Change Page 2 Page 3
With the exception of the advanced testing method's presented in the C5 posts above, I didn't learn anything. Oh, and perhaps I found reason to support the idea that when one asks for advice, they only answers they want need to support the path forward as they perceive it; much like when my daughters call for advice and argue with me (summarily dismiss without due consideration) over my thoughts.
While there may have been reasons for it, sadly, I don't recall the OP ever responding to the myriad of good suggestions. It was likely a costly mistake; perhaps we'll never know.
On the other hand and speaking of perceptions, I may have missed something???
What were you expecting to learn here ??…these weren’t really “advanced” methods and this issue could have been narrowed down with a “clear flood crank” and the hood not even opened.
The "advanced" reference only meant to emphasize the idea that few shops employ that kind of technology and this old school guy learned something; even the dealerships (TAC staff?) generally don't employ that kind of testing. There was no expectation to learn anything, only that everyone who participates in these threads is thinking that their suggestion might be helpful and knowing the end result/solution helps to reinforce someone's idea.
But the worst part of this is embedded in the following quote from the OP in post #13:
STARTED TAC CASE #9-152227222101. TAC RECOMMENDED REMOVING SPARK PLUGS AND INSPECTING WITH SCOPE TO LOOK FOR INTERNAL DAMAGE. NONE NOTED. WILL NEED CYLINDER HEADS REMOVED TO INSPECT PISTONS FOR DAMAGE. POSSIBLE DROPPED VALVE. TOTAL TEAR DOWN COST $3335. CUSTOMER DECLINED FURTHER DIAGNOSTIC PROCEDURES.
It seems obvious that the technical assistance provided by the TAC contact in this case was not helpful; does anyone review this kind of situation where the pros are so far off the mark? Probable not, especially in this case where the fix will likely remain unknown to the original dealership.
Since there was no damage noted, the next step does not appear to be removing the heads. Simply running a traditional compression test or removing the valve covers for valve train inspection would have provided the solution. In fact, the compression test by itself would not have provided the absolute answer, but as the pics above show, the removal of the valve covers instantly revealed the source of the problem.
The fact that the engine would start (the OP never said how noisy it was) was a clue and considering all the good advice, the resulting path followed was disappointing.
I can't express how grateful I am to this forum, those that responded with their input and especially C5DIAG. I now know how to proceed with a fix for my car, and it is not with a new engine.
All I can say is I hope none of you reading this have your car break down 1200 miles from home in a one horse town in southern Illinois or any other state; especially PCGUY2U, walk a mile in my shoes.
The "advanced" reference only meant to emphasize the idea that few shops employ that kind of technology and this old school guy learned something; even the dealerships (TAC staff?) generally don't employ that kind of testing. There was no expectation to learn anything, only that everyone who participates in these threads is thinking that their suggestion might be helpful and knowing the end result/solution helps to reinforce someone's idea.
But the worst part of this is embedded in the following quote from the OP in post #13:
STARTED TAC CASE #9-152227222101. TAC RECOMMENDED REMOVING SPARK PLUGS AND INSPECTING WITH SCOPE TO LOOK FOR INTERNAL DAMAGE. NONE NOTED. WILL NEED CYLINDER HEADS REMOVED TO INSPECT PISTONS FOR DAMAGE. POSSIBLE DROPPED VALVE. TOTAL TEAR DOWN COST $3335. CUSTOMER DECLINED FURTHER DIAGNOSTIC PROCEDURES.
It seems obvious that the technical assistance provided by the TAC contact in this case was not helpful; does anyone review this kind of situation where the pros are so far off the mark? Probable not, especially in this case where the fix will likely remain unknown to the original dealership.
Since there was no damage noted, the next step does not appear to be removing the heads. Simply running a traditional compression test or removing the valve covers for valve train inspection would have provided the solution. In fact, the compression test by itself would not have provided the absolute answer, but as the pics above show, the removal of the valve covers instantly revealed the source of the problem.
The fact that the engine would start (the OP never said how noisy it was) was a clue and considering all the good advice, the resulting path followed was disappointing.
Nick
Well sometimes this technology is the ONLY way to diagnose some driveability concerns...it has been around for over 30 years so it's not something new...dealerships have the labscope I use but they only use it for NVH (Noise, Vibration, Harshness)....dealerships don't make money diagnosing so they will only replace parts and hopefully that fixes the problem and if it doesn't well the customer is out a lot of money in parts and labor...I just call it incompetence by this particular dealership...if that Tech had to open up a TAC Case for an "erratic" MAP sensor issue that's incompetence with a capital I.
Today got my car running thanks to C5 DIAG! C5DIAG is very informed and competent. I wouldn't have been able to fix my car without his help. Fortunately he is in close proximity to me and he was with me all the way. What else can I say but thank you!
Thanks Dave !!…we had to wait a few weeks for the OEM parts but the repair was a success…compression back on # 8 and all codes cleared with nothing returning and no misfires…MAP sensor reading back to normal due to the intake valve hanging open…cleaned throttle body which was pretty dirty but battery will need replacing.
Gotta hand it to C5 Diag for the amazing support on this one. Saving this guy thousands of dollars and potentially weeks or more of not having his car. Well done!
Thanks !!….another reason NOT to take your car to a dealership for a diagnosis like this one…just got done with the oil change with no needle bearings found in the oil !!
Thanks !!….another reason NOT to take your car to a dealership for a diagnosis like this one…just got done with the oil change with no needle bearings found in the oil !!
Would you please share the part numbers for the rocker, seal, and springs.
