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  #49  
Old 07-16-2010, 11:56 AM
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Re: Misfires - '02 JGC Limited...

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Originally Posted by rebuilder View Post
Hey Kyle,
Fellow Georgian here not too far from you. Got my 02 from a kid up in Dahlonega recently.
I'm staying tuned to see what your problem is. I've been having computer probs. Just received my 4th warranty replacement for a "rebuilt" computer but haven't installed it yet.
Best of luck!
how many miles do you have? i have 107k...

I am struggling to toss the truck because its in such great shape.
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  #50  
Old 07-16-2010, 03:23 PM
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Re: Misfires - '02 JGC Limited...

I can understand that this whole story is making you crazy, it would do it to me at least. I hope that they will finally find the problem without too much money wasted. I'm very curious what they finally will find.
Good luck.
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  #51  
Old 07-16-2010, 03:27 PM
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Re: Misfires - '02 JGC Limited...

By the way, did you finally put new cam and crank sensors in? The last i red was that you cleaned them.
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  #52  
Old 07-16-2010, 05:07 PM
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Re: Misfires - '02 JGC Limited...

i did put the new sensor in... result... i have a new sensor. won't have to worry about that sensor anymore... lol...

well.. as far as repairs go.. $80 for the initial diags... $90 for the compression test.

Good News... rings and valves are good. 171-173PSI (or something)

Bad news... there is a leak in the head gaskets. allowing compression into the coolant and coolant into the cylinder. evidently.. there is a known problem where electrolysis causes a lightning bolt patterned etch in the head. This allows such a leak.

the tear down to find out if the head or the head gasket is bad... $350

kyle
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  #53  
Old 07-17-2010, 03:07 PM
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Re: Misfires - '02 JGC Limited...

I had red something about this before. Check out this site with some more info and pictures. http://www.denlorstools.com/autoblog...-head-gasket/.
This seems to be a common problem on 4.7 engines.
But does your car have problems with coolant level going down without external leaks?
There is a solution to prevent the electrolysis in the cooling system. See next site, where they sell a Zinc anode electrode. http://www.teamgrandcherokee.com/Coo...tem/index.html. Seems to be worth to try out for 15 USD only.
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  #54  
Old 07-17-2010, 06:47 PM
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Re: Misfires - '02 JGC Limited...

Have a look at the next site regarding the galvanic corrosion on the timing belt cover. Looks like that this engine really needs some protection against this type of corrosion to prevent future problems. Anybody knows if using the Zinc anode electrode will prevent the internal corrosion?
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  #55  
Old 07-17-2010, 06:48 PM
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Re: Misfires - '02 JGC Limited...

And now with the site address: http://www.nagca.com/forum/showthread.php?t=38876
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  #56  
Old 07-19-2010, 07:33 AM
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Re: Misfires - '02 JGC Limited...

Quote:
Originally Posted by Frango100 View Post
Have a look at the next site regarding the galvanic corrosion on the timing belt cover. Looks like that this engine really needs some protection against this type of corrosion to prevent future problems. Anybody knows if using the Zinc anode electrode will prevent the internal corrosion?
Honestly, I would say it should work. Do it and keep an eye on the rod. See if it's eating the rod away after a few months. The Zinc is a sacrificial metal and the corrosion will "eat the zinc" instead of the engine. Eventually the zinc will have to be replaced because once it's gone, the corrosion will move back to the engine.

This is the same concept that's used on salt water boats and hot water heaters. Salt water boats have a zinc plate near the prop to it corrodes the plate and not the prop. Hot water heaters have a sacrificial rod in them so it corrodes the rod and not the water heater.
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Old 07-23-2010, 11:03 AM
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Re: Misfires - '02 JGC Limited...

Frango...

This is exactly the problem. and its a $2500 repair.

the good thing is that I'm getting both heads re-worked and all the valves cleaned up.

they are also going to add the latest PCM firmware free of charge.

more details when i get it back..

kyle
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  #58  
Old 07-23-2010, 06:20 PM
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Re: Misfires - '02 JGC Limited...

Did you see the cylinder heads? Maybe some pictures? Quite an expensive repair by the way. Being something seemingly common on the 4.7, jeep should have done something about it. Just wondering if placing the Zinc anode electrode into the radiator is the right place to prevent the corrosion on the heads
Or is there any other place to put it?
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  #59  
Old 07-24-2010, 06:06 PM
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Re: Misfires - '02 JGC Limited...

Quote:
Originally Posted by Frango100 View Post
Did you see the cylinder heads? Maybe some pictures? Quite an expensive repair by the way. Being something seemingly common on the 4.7, jeep should have done something about it. Just wondering if placing the Zinc anode electrode into the radiator is the right place to prevent the corrosion on the heads
Or is there any other place to put it?
I don't have any pictures.. i was traveling during the repair. it really did suck... very expensive. they did say that the only plugs that belong in that engine are champion plugs. the cheap copper ones. the other thing they said is that using the right corrosion resistant coolant that mopar uses is the only thing that should ever be in the engine. also. this problem is likely related to an overheating engine. this engine gets really dumb when it over heats.. thats probably the worst thing you can do to this engine. Oddly, it is overheating way before the light even comes on.

i didn't ask about the electrode, i don't know if they would know about it or not.

my biggest hope is that this thread will help others.

Kyle
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  #60  
Old 07-25-2010, 02:57 PM
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Re: Misfires - '02 JGC Limited...

Wonder if the original jeep HOAT cooling liquid would make any difference to prevent galvanic corrosion. As far as i know this has to do with 2 metals of a different type and a liquid. Maybe that some expert on this can explain it better and what would be the solution for it
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