Grey smoke out of my tailpipe

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HangryMachinist

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On my way to work my Jeep gave me a P0304 code. After inspecting it looks like I may need a tune up. So that's what I did last night.

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So after I changed all my spark plugs I went for a drive. When I turned the Jeep on the error code was gone. After a minute of driving I came to a stop and saw a lot of grey smoke coming from my tailpipe. I pulled into a parking lot to make sure I was not on fire. It smells like burning paper! And only out of my tailpipe. What would cause this? Please help.
 

stoney126

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The code cleared on its own? Is that a 5.7? Is the misfire code completely cleared or it a softcode or pending code? What's the mileage? What type of plugs did you put back in?
Any upper valve train noise like lifters?
 

HangryMachinist

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so its the 4.7 from a 2002 Jeep WJ. I replaced the plugs with the direct replacement. I got that info from WJJEEPS. It did clear on its own but then came back only 6 minutes later. The jeep after the new plugs was running very smooth. I have 101k miles on it now.
 

stoney126

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Did you do both intake and exhaust? . 4.7s like to kick out the rocker arms but it wouldn't be running smooth.
Without doing a compression check and leak down test I can only speculate .
Could be a valve issue or possibly a ring issue
 

stoney126

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Dang! Well at least you didn't over heat it so it'll just be head gaskets.

Sorry man that blows.
 
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IronPercheron

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OK so now let see how entailed thats going to be. Thanks for your feed back!
[emoji51]

daaaaaaang

I hate to see that hoss...

My .02 on going into any engine is pull it out and go back rebuilt.

Pull it out and scatter it.... get the connecting rods checked (smashing water tends to bend those) and go back with fresh rings, bearings, seals for the bottom end etc... etc.

Go to a ARP head stud kit and felpro head gaskets and youll be good to go.

Idk what kind of machine shop you work in but def. Hone and cross hatch cylinders (coolant is not lubricant)
Check line bore, freshen up the heads etc.

I like the 4.7's. Good lil small blocks, ive seen em over 300k... this is disappointing :-(


OK so now let see how entailed thats going to be. Thanks for your feed back!

Sent from my SM-G920V using Tapatalk
 

HangryMachinist

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Im having it towed to my friends shop tomorrow. He was thinking it could be something else. So at this point I'm willing to pay to have him look at it just in case its just a valve thing. I really don't want it to be a gasket or worse. I have my fingers crossed.
 
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WJ - Firefly

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Luck to you! I changed head gaskets in a Chevy 4.3 vortec about 8 years ago, in my side lot ( I don't have a garage). The biggest problem I had was that it was in a safari van and I did ot with the engine in the vehicle. GM designed it such that there is no way to turn any fastener that is not on the very front of the engine without some special tool and getting into some strange positions... :sunglasses:
 
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HangryMachinist

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So after I got it to the shop we start it up and now it smells like coolant. CRAP! I liked it better when I thought it smelled like burned paper. So until I have the money and time My jeep will not be operational. :(
Apparently my hydrocarbon level is 1143ppm. Im going to do the following to the jeep;

-Rework both heads and have them pressure tested ( or replace with re-manufactured ones )
-New Timing chain Tensioners
-New radiator hoses
-New water pump
-New Oxygen sensors 2x rear and 1x front
-All new fluids ( oil, coolant, and power steering

Let me know if I should do other things sense I will have everything off on the top end
 

HangryMachinist

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@HangryMachinist you may want to check/inspect that transmission fluid, if it is automatic, just to make sure there was no mixture of coolant there. Hope to see her running soon!
I will be changing all mt fluids for sure.

From what I've read head issues aren't uncommon on the 4.7. Sucks it happened to you.
The 4.7's will have head problems if you overheat them. But normally its not the gasket that goes. I will also be upgrading my cooling system so that I dont have to worry as much on overheating.
 

HangryMachinist

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So now that its repaired and driving strong I think I know what that smoky smell was. I believe it was the coolant going into the catalytic converter. After the first start up, after everything was back on, it had that smell coming out of the tail pipe. It was much fainter but that was the smell I was smelling from before. After the 30 minute test drive it went away. :)