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rebuilt 4.0 I6 weird noise , vibrations

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Old 05-31-2012, 06:42 PM
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Exclamation rebuilt 4.0 I6 weird noise , vibrations

well i'll start off by saying i rebuilt this engine for my 87 jeep cherokee, i salvaged the block from a junkyard ,my old engine threw a rod just completely thrashed the engine so i decided i wasnt ready to let the heep go so i rebuilt the engine new bearings, rings etc.

well when i slapped the thing into my jeep and started it a tingy sound came from the catlyc converter i tapped it and their is something in the converter so maybe thats giving me the tingy sputtery like sound but the engine also is vibrating like crazy the whole jeep vibrates cause of it ..alll of the vacuums have been checked for leaking , the timing was checked, new motor mounts....im gonna check he compression this weekend but if anyone has any input let me know. would be greatly apprecited

heres a video of the engine and the exhaust thing, also it did stall when i tapped the converter.
http://youtu.be/Xa0bTu_Ekn4
Old 05-31-2012, 06:52 PM
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Do I see smoke coming out between the muffler and cat? Looks like you may have an exhaust leak.

Did you check out your exhaust manifold for cracks when you had the engine out?

How is your tranny mount?
Old 05-31-2012, 07:30 PM
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Did you replace the cam bearings when you rebuilt it.
Old 05-31-2012, 07:36 PM
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Also about 17 seconds into your video i could have swore i seen your spark plug wire arching. Check to be sure they are in the cap tight and not arching on any nearby metal.
Old 05-31-2012, 09:40 PM
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Originally Posted by grsmnky1
Also about 17 seconds into your video i could have swore i seen your spark plug wire arching. Check to be sure they are in the cap tight and not arching on any nearby metal.
I saw the same thing of th #5 cylinder
Old 05-31-2012, 09:45 PM
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See same thing 5 bad plug wire
Old 06-04-2012, 06:16 PM
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Hey everyone thanks for the quick replies, but yes i have replaced the Spark plugs and Wires since the video, jeep has new motor and transmission mounts. new fuel injector 0-rings,new bearing including cam, i removed the pieces of medal inside the exhaust that cause the tingy sound. but after the engines been running for a while i still smell gas...almost like the engines running rich but imabout outta ideas..besides checking the sensors....oh and also the smoke coming from exhaust is cause i left the exhaust on the ground and my old engine just spit out oil everywhere when the rod blew out of it.
Old 06-04-2012, 07:22 PM
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two questions left to be asked,

How hot is your cam or is a stock grind as well as how is harmonic balancer. Could be the wrong balancer for the crank.
Old 06-04-2012, 08:30 PM
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Cam was in very good condition, i checked the lobes and what not, new lifters, rods and arm, and the balancer was the same one that came with the engine its not twisted or anything just a bit dirty cleaned up real good.....I went and bought a vaccuum pressure gauge/fuel pressure gauge so im gonna do some testing
Old 06-05-2012, 01:17 AM
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If the motor dies when you tap the cat, I'd put money on the cat being plugged. I've had them break off chunks of the honeycomb, which find their way to the outlet and block it. Put a vacuum gauge on the motor and see if the reading steadily drops.
Old 06-05-2012, 04:50 AM
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You've probably already have done this, but check your firing order again. Also, did you use the correct method for installing the distributor? And finally, IS THAT A FRAM OIL FILTER YOU'RE USING???!!!

It sounds to me that maybe a couple wires are reversed, that might account or that "puff" sound I'm hearing in the exhaust and the unburt fuel smell.

Last edited by Cherockee; 06-05-2012 at 04:52 AM.
Old 06-05-2012, 06:47 AM
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Radi and Cherockee make very good points here.....
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Old 06-05-2012, 04:52 PM
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interesting thing about the firing order i'll double check it,,, as for the fram filter whats wrong with fram ? as for the cat converter i took out the whole exhaut and shook it out over my shoulder and stuff fell out almost looked like pieces of a weld now after i installed it no "tingy" noise...Im real interested about the firing order though im gonna double check it thanks Cruiser54 for tip and pic.
Old 06-05-2012, 06:24 PM
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Fram filters are of notorious poor quality and have poor anti-drainback valves so they drain out when you shut the engine off. Upon re-start, you lubricate your engine's vital parts with air instead of oil for a little bit. Trust us on this.
Old 06-05-2012, 11:17 PM
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Originally Posted by cruiser54
Upon re-start, you lubricate your engine's vital parts with air instead of oil for a little bit. Trust us on this.
It's OK. The air in my shop has Lucas added to it.


Seriously, I never bought into the "this filter is crap, that oil turns back into coal tar" stuff, figuring any major brand was probably good enough.... until I screwed a Fram on and got the start up knock. Took it off and it went away.


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