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Unread 10-04-2013, 11:00 PM   #1
samuraisavr
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03 TJ 2.4 knocking?

Hey all. I got a noise coming from the engine and I can't really pinpoint where it is likely coming from. Oils pressure is good, I don't see any metallic residue in the oil. If the jeep is under a good load, there is no knock. If the jeep is idling, no knock. If I just try to hold a given speed, be it 15 or 55 I get a knocking sound. I know this is a goofy description, but that's the best way to explain it. Anyone got any input that may be helpful? Thanks in advance.

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Unread 10-05-2013, 08:11 AM   #2
samuraisavr
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Morning bump. Hoping to start tearing into the jeep, but still unsure where to start. Thanks again for any help in advance...
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Unread 10-05-2013, 08:24 AM   #3
Jeepsr4me
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post a video of the sounds. As most can not guess what a sound COULD be cause it can be a million things.
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Unread 10-05-2013, 08:35 AM   #4
samuraisavr
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I'll try to get a vid posted. It'll be hard to do since it doesn't knock at idle, only at a constant speed. Not during acceleration or deceleration.
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Unread 10-24-2013, 10:11 PM   #5
samuraisavr
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Just an update for anyone who may encounter a similar situation. I have established that the sound was coming from the front cover area and decided to research further. I now have the entire front cover assembly off and upon visual inspection I can see that my timing belt is VERY sloppy. So much so that the tensioner and idler pulley can be spun freely by hand. I can see scoring on the block as well as the back side of the front cover where the tensioner pulley has been making contact. I cannot guarantee that this is the culprit of the noise just yet, but I am fairly sure a new belt and tensioner will fix the problem. Updates to come in the very near future...
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Unread 10-25-2013, 04:41 AM   #6
4banged
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Do the waterpump while you're at it and prepare yourself ... That timing belt is a biatch of a job.
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Unread 10-25-2013, 08:16 PM   #7
samuraisavr
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Got any tips or tricks. Anything in particular to look out for? Thanks for the heads up.
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Unread 10-26-2013, 05:36 AM   #8
4banged
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You'll need the right puller for the harmonic/crank pulley...I used a loaner from autozone. The fun part is getting the new belt on with all marks lined up...mark on pulley lines up to mark behind, and there are marks on both cam sprockets that need to line up to each other as well all while you're trying to get the belt on...it would be easier with 3 hands. I put mine on and thought I had it right...started up and idled fine but there was a noticeable loss of power. I took it all apart and moved belt one notch and now its perfect. I'm already not looking forward to the next belt change.
And check rockauto website for price...pretty sure they had best price for belt and water pump. Good luck.
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Unread 10-31-2013, 08:00 PM   #9
samuraisavr
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One more update: Timing belt is on and running great..... Oil pressure is good, I can feel a noticeable bump in power now that it is timed correctly.... but.... IT STILL KNOCKS. My next course of action is to pull the oil pan and valve cover and check for anything jumping out at me in there. I am actually at a total loss right now. I've had piston skirts break, rod bearings spun, main bearings spun, and nothing fits this description. Only way to figure this out is to get dirty I guess. I'll keep the forums updated since there is very little info out there on these little bastard motors.
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Unread 10-31-2013, 10:17 PM   #10
chris142
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Quote:
Originally Posted by 4banged View Post
Do the waterpump while you're at it and prepare yourself ... That timing belt is a biatch of a job.
I did one and thought it sas easy
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Unread 11-01-2013, 04:39 AM   #11
4banged
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Quote:
Originally Posted by samuraisavr View Post
One more update: Timing belt is on and running great..... Oil pressure is good, I can feel a noticeable bump in power now that it is timed correctly.... but.... IT STILL KNOCKS. My next course of action is to pull the oil pan and valve cover and check for anything jumping out at me in there. I am actually at a total loss right now. I've had piston skirts break, rod bearings spun, main bearings spun, and nothing fits this description. Only way to figure this out is to get dirty I guess. I'll keep the forums updated since there is very little info out there on these little bastard motors.
I always try to bump 2.4 threads because as you said not much info out there. I know this isn't what's causing your noise but while you're looking around pop off the exhaust manifold cover and look for cracks in the exhaust manifold. Good luck and let us know what you figure out.
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Unread 11-04-2013, 07:43 PM   #12
samuraisavr
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I took the jeep to a mechanic friend of mine and the consensus is that I have a bad wrist pin. I'll be tearing into it tonight or tomorrow morning to isolate exactly which one. The next step is deciding whether to just slap some new pistons and wrist pins in and call it good or do I go ahead and swap a srt4 forged bottom end in and throw some boost to it?
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Unread 11-06-2013, 04:25 AM   #13
4banged
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Interesting, please take some photos of what you find. As for boost, its been done with a turbo on this motor a few times but I've been considering a supercharger like an m90 off an old Buick...its been done on the 4.0...I need to dry fit one to see if it will fit...the 2.4 is crammed up against the fire wall and the m90 is so long I don't know if it will fit (they make a universal adapter to use it on any motor). I'm just looking for 6lb boost using something like the split sec enricher.
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Unread 11-19-2013, 08:03 PM   #14
samuraisavr
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UPDATE: Pan is off and valve cover is off. Visually, NOTHING STANDS OUT. Does anyone have any ideas. I'm going to reassemble the engine and fire it up to get some audio for you all to mull over. I'm at a point where I may just burn it to the ground...But seriously, I'm getting pretty damn frustrated.
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Unread 11-24-2013, 05:50 PM   #15
4banged
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Ok, this is a stretch but did you reset the PCM after the timing belt replacement? It might be trying to run off the old learned timing curve that was built around your loose belt. Long shot but figured I would ask...
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