Guys, I need your help badly.

Background info.: 1988 Cherokee, 4.7L stroker with HO head (6130 casting), engine has less than 5k miles on it and is just over a year old.

Was heading to work the other day on my XJ and the engine started to misfire and go nuts. Turned back around and hopped into my MJ. Anyway, I've been trying to diagnose it tonight. I started with the fuel injectors. They're all fine. Checked my dizzy and wires, they're fine (just got all new stuff about two weeks ago). Pulled my spark plugs, all fine EXCEPT the one in cylinder #2. It was fouled with oil. Cleaned it off, started it and let if run a minute or two. Pulled that plug again, fouled with oil again. However, I noticed this time when I pulled the plug, smoke starting pouring out of the plug hole. I don't think it was burning oil, as it was not blue in color nor did it smell like burnt oil. Suppose it could be gas, but didn't really smell like that either. Anyway, the PCV elbow has some frothy looking oil inside. I haven't pulled the valve cover yet, but will likely do that soon.

My fear is that the piston rings are FUBARed. I'd like to add that with the engine running, it seems to have a noticeable clanking noise. Has been doing this for a few weeks now, but I didn't think much of it because the XJ makes lots of strange noises under the hood. Going to rent a compression tester tomorrow from the parts store and check that.

Anyone have any ideas of what might be going on? If this engine is already FUBARed, I'm going to be pissed.

 

Sorry man. So how many miles did you get out of her? And what killed it? Fram filter? Overheated?

Edit..whoops, 5K...... yea, of course check compression.

 

#2 piston rings, and/or oil control ring, likely broken. Cracked piston a remote possibility.

Non-stock engines have a shorter life, but 5,000 miles is really short. Could have been a machining or assembly error.

 

This is what I feared... will be checking compression as soon as I get a tester tomorrow... I'll be damned if I get screw on this deal. The guy who built this has supposedly 30+ years of engine building under his belt, from mild to wild builds. His warranty covers 12k miles/1 year.

 

Alex, I'll take cracked Cylinder wall for $1000

 

Good thing you've got your MJ to drive while he fixes your engine.

 

Cool! Contact him. He might not be happy you kept going with it having a "noticeable clanking noise. Has been doing this for a few weeks now"
but hey, a warranty is just that! ( I do hear you, mine knocks, always has)

 

Don't say that...

Knock on wood.

True, but he doesn't have to know that... lol. Besides, the misfiring just happened. Who's to say said clanking noise has anything to do with it? But it's probably relevant...

 

its hard sometimes to tell what noises a 4.0 makes to be concerned with, and wich ones are "normal"

Mine makes all kinds of funny noises.. makes me lose my hair sometimes.. but keeps putting out like a champ!

 

Edit...are you familiar with a wet/dry compression test?

Do a first set of #'s, warm, throttle OPEN. (all plugs out) I like to do 5 to seven strokes to get a max figure. Pro's might say to do less. THEN with a vinyl tube or a turkey baster or something add a couple of tablespoons of oil. Crank it a sec to get it around the rings, then take a second set of #'s. If the # jumps up wet, it's the piston/rings. If it's low and doesn't improve it's a valve or the head gasket.

You can google or U-Tube search "wet/dry compression test" and the like if you are not familiar with the process.

You could also apply compressed air to #2 at TDC on compression and see where it comes out. Or in your case rotating it farther to bring the piston down will expose the cyl wall. Too far will open the exhaust valve, of course.

 

Yeah, you are putting all your text in bold. Stop that.


Oh, and your engine is toast. You won't know what's really wrong until you tear it down.


If you kept going when there was a clanking noise, you gave the shop all the justification they need to void your warranty.

 

How's this for text?

Not relevant for helping me figure out what's going on.

 

Results to my compression test... Each cylinder was tested in the same manner to rule out user error:



I know cylinder 2 is messed up and reason being is because there is coolant shooting out when the plugs were all removed and engine being turned over... so, what does that mean? Head gasket? Cracked cylinder wall? Something else?

 

Neither is your bolding.

 

Yes.

It means head gasket, cracked cylinder wall, or something else. You won't know until you open it up. Given that this came after a few weeks of clanking noise, it's probably pretty bad.


Nobody can tell you what is going on inside your engine. You need to open it up.