Forum Posts

slowfive0
Dec 14, 2021
In AFM/DOD Q&A
I have a 2015 6.2 (L86) engine that had a stuck #7 intake lifter. I was able to unstick the lifter using the special tool, but now I have a small miss that counts up only at idle on #7. Fuel trims are negative, but very low and are both very close to each other at all rpms EXCEPT idle. At idle Bank1 is skewed negative by 7 points (LTFT1: -10 vs LTFT2: -3). I replaced that injector and made no change. All the injector seals were intact. NOTE: Misfires only count up on #7 at idle or at extremely low rpms. It never sets any misfire codes, but you can feel the roughness in the steering wheel and it doesn't idle cleanly. It does set fuel trim imbalance codes. Sometimes just bank 1, sometimes both banks; i.e. P219a/P219b. I checked compression and #7 had 230psi & #5 had 260psi. I put a couple of squirts of oil into cylinder #7 and the reading went up to 260psi which would point towards a ring issue. I was leaning towards a damaged camshaft issue, but am having hell trying to get my dial indicator setup to work (brake booster in the way) so I can't 100% verify the lift vs a k/g cylinder. For what its worth, I didn't see the dial indicator needle jump when checking the lift over the nose of the cam (which might indicate damage). Lift reading was questionable though as mentioned due to the booster. Maybe the lifter or rocker arm (bearings) are damaged and have some play in it or something weird like that but I would expect misfires at all rpms......? Maybe not....? The low compression seems to point to a camshaft problem (truck was great before), but the compression jumping up with the oil test has me perplexed.......Appreciate any thoughts/suggestions before I dive into this pos ;-) Thank you.
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slowfive0
Nov 20, 2021
In AFM/DOD Q&A
#7 intake lifter is stuck. I'm trying to get the stuck lifter to release. As I tap on the tool, the lifter actually goes up the bore. I have to keep pushing the pushrod/lifter back down. If I keep pressure on the pushrod, it feels like I need to hold the tool so it doesn't bounce so bad when I tap on it. If I hold the tool and let the pushrod/lifter vibrate up the bore, the lifter will get high enough in the bore that that the tip of the tool must be getting into the edge of the machined area on the side of the lifter (and ends up burring up the end of the tool). Is that normal? I may be overthinking this but I don't want to screw it up and haven't had much luck getting it to release after tapping on it for 10 - 15 mins (lightly). Thank you.
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slowfive0
Nov 12, 2021
In AFM/DOD Q&A
Hello, another bent pushrod/stuck lifter customer here. Ordered your release tool and when I got the covers off, I found a bent pushrod on #7 intake as well as #4 intake valves. #7 was making the racket and the rocker was loose. I checked the lift with a dial indicator and observed no damage and same lift as #1. At that point, the lifter wasn't stuck so I was able to replace the pushrods. NOTE: I couldn't push #7 pushrod down at the pushrod so I assumed all was good. Started it back up and it's tapping away.....Tore it back down and #7 rocker is sloppy loose (#4 is not). I pulled the intake off to try the release procedure and had to stop due to the rain. Am I on the right track here? Is maybe the lifter damaged and not going to stay locked once I release it? NOTE: owned and maintained the truck since new. Now has 170,000 miles on it and has been problem free til now. Was on a trip and started hearing it tapping whenever it would go into 4 cylinder mode. I did my best to either give it a little more gas or let off so it would kick out of 4 cylinder mode to minimize any damage. I got about 200 miles and was driving along and it started missing, dash lights went off, mil light starting flashing (has P0300 in memory), etc. Towed it home and here I am. Appreciate your site and help---thank you.
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