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Where would I start??

vertrx

NAXJA Forum User
Location
South Carolina
2001 XJ, motor recently replaced about 9 months ago with a used motor from another 2001 Had about 140,000 on it.

That said, running fine, but now have issues. Its giving codes 0300, 0304,0306, running real rough and interestingly there's white smoke coming out the tailpipe! That may be a red herring though as the coolant is fine, oil has no coolant in it, but I think the motor has that head with the issues.

I've changed plugs with NGK's, and fuel injectors. Cooling system new parts. But the catalytic converters are original, not replaced, so where do i start?

Could it be the catalytic converter? Vacuum leak? Coils? The weird thing is the white smoke since I don't see that come up in a search on those codes...
 
The codes are there for a reason, troubleshoot based on the codes. If the cats are original, it is likely the O2 sensors are also original, and require replacement. Test the O2 sensors. Test the fuel injectors, and inspect the injector wire harness for damage and failed wire splices. Test the other OBD sensors.

During an engine swap, the wire harnesses get jerked around pretty good, make sure there are no failed wire splices, melted/chafed wire insulation, and that all of the ground points are clean and properly snug.
 
Will do. I think I'll check the coil first. I think that cylinders 3 and 6 are on the same coil?
Also, I saw a you tube video where a guy tested the injectors. He used a set of tools in a plastic box and attached one of the pieces to the fuel injector? It looked like the plastic ball or tool he used started flashing like an LED inside. What would that tool be called?

That said, why the white smoke?
 
http://www.naxja.org/forum/showthread.php?t=1076299

I would consider a failed head gasket, cracked head, or cracked block.

If the replacement engine was mostly intact when dropped into your vehicle, then all of the above is suspect, but the gasket might be the first place to look into. White vapor out of the tailpipe continuous? Just for a moment, or two after start up? Lots, or little?

From what I remember the years of your head are prone to cracking after an overheating engine condition. The better made head is called a TUPY, (click on above link).

Unless you have all the tools, and diagnostic ones, UV dye/black light as well, check into it. However, if not, then discuss with most shops that do, and see what they can check for you. Probably an hour's worth of labor costs to determine the condition. Go from there.

I have no way to check codes on a RENIX XJ, so am not familiar with that.., but others here do, and will advise you on those code issues you have.

Best wishes.
 
Thank you. Its not a Renix, so I think that eliminates one issue. I am worried about the head issue and all its problems since that is why the first motor went south...actually west as it ended its journey in the middle of the winter in Nebraska. Towed it home! And yes, that is the head cracking year.

I was thinking to follow the codes as the first response was saying since those seem to indicate cylinder firing issues.

That white smoke is continuous though, so troubling while the engine is running rough.

Also, that fuel injector tester is called a noid or something. Interesting concept.
 
The P0300 code is a random misfire, the P0304 is
cylinder #4 misfire, and P0306 is cyl. #6 misfire.

I'd take a look at the plugs on number 4 and 6 cylinders,
and see if bubbles show up in the radiator when idleing.

Unfortunately it sounds like a cracked head....
 
If you suspect head issues, confirm by testing. The 2000-01 0331 head is prone to cracking, but not all 0331 heads will crack. A compression test, cylinder leak down test, a combustion byproduct test kit for the coolant, and an oil sample sent to Blackstone Labs will tell you exactly what you need to know.
 
Will do. I think I'll check the coil first. I think that cylinders 3 and 6 are on the same coil?
Also, I saw a you tube video where a guy tested the injectors. He used a set of tools in a plastic box and attached one of the pieces to the fuel injector? It looked like the plastic ball or tool he used started flashing like an LED inside. What would that tool be called?
They are called "noid lights", basically they are just lights that connect to the injector wire--when the computer sends an injector pulse, the light takes some of the voltage
 
Quick test would be pressurize cooling system, let it set for a few minutes, pull the plugs and crank it. Look for coolant coming out. Not always a perfect end all test but if it's that bad it's a quick check that works.
 
Ok, so it sounds like it might be a cracked head subject to some further testing. I'll check the plugs if they show any moisture.

I'll check radiator to see if it has bubbles in it? Will they show up before or after thermostat opens...hot or cold?

And I'll try pressurizing the cooling system. I suppose I pressurize it with the pressure equipment in place while I crank the engine? With spark plugs out?

If none of that is determinative, I'll have to go the expensive route that Tim_MN suggested. That will get expensive, so leave that for last. Besides, I'd have to trailer the Jeep to the shop!!

Thank you ehall for the noid light explanation!!
 
Carrying the matter forward, say I need a new cylinder head due to a crack, do I buy a rebuilt 0331 which it seems to me would have the same cracking issue or would I look for the TUPY(?) if it fits? A rebuilt one or one out of the junkyard?
 
Ok, so it sounds like it might be a cracked head subject to some further testing. I'll check the plugs if they show any moisture.

I'll check radiator to see if it has bubbles in it? Will they show up before or after thermostat opens...hot or cold?
..........
The plugs might not show signs of moisture, but they will
be discolored compared to plugs on the good cylinders.

The bubbles will show up after warm-up. It might take that
much time for the cracks to open up, if that's the problem.
There will also be sooty residue floating of top of the
coolant in the overflow bottle.

The fact that the problem cylinders aren't adjacent, makes
me think the head is cracked. A headgasket will sometimes
blow between two adjacent cylinders. The only surefire way
to tell if it's a headgasket failure or a cracked head is to
pull the head, since the symptoms are the same...
 
I have a 2000 XJ. When this happened to me....it was the head and/or gaskets. I didn't check. I knew what it was and purchased a TUPY head from a newer Wrangler and had the new head reworked at the machine shop and then paid a mechanic to swap the heads for me. Problem solved. I can't promise you that it is the head or gasket. But I can say that I would not pull that head without replacing it with a TUPY head. Too much work. Gasket or head....who cares? You get both when you swap the head for the upgrade.

I did not have a coolant or oil leak either way through my head. Nothing was contaminated or violated. Just misfire codes and obvious misfires when driving. A couple of times the engine got so pissed it entered limp-mode and started flashing the CEL. Had to pull over, turn off engine, use my OBDII reader to clear the codes, restart, resume minor misfires, and continue down the road. Real PITA.

Of course....it may not be the head and/or gasket. But it was for me. And I don't know which one. Probably the head. Quite likely just worn out valves. It was around 165,000 miles or so at the time (205,000ish now). Who knows? But my gut instinct, for the 2000 and 2001 XJ's, when random misfires start up....it's the head/valves/gasket. And again...rebuild a TUPY, not the original.

I could be wrong.
 
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Not hard to find a TUPY head. Get one off of ANY wrangler made after 2002 with a 4.0. They are ALL TUPY heads. And for my 2000 XJ it was direct swap. No one would guarantee a direct swap for me, but it was exact. Every bolt. Obviously, individual results may vary. My XJ is east coast and it was exact for me.

Don't harass the parts yard guy. He has no idea what a TUPY head is and does not want to go searching heads for casting numbers. Just get a wrangler 4.0 head from after 2002 and have it remanufactured at your local machine/head shop. The bad heads were swapped over around 2001.5 manufacture year. Supposedly ALL of the 2002s were TUPY heads. Go later than 2002 to be safe.

I'm just some guy with a jeep. I could be wrong.
 
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I'm wondering if I go to the picknpull, I'll have to do the job twice, actually removing the head twice and installing once. There are several vehicles with the TUPY head from what I recollect. Looks like the SOHC with or without cam is $49.95 with $10 core charge.

Just not sure I want to work at this in this heat and humidity.

Of course then I'll have to have it rebuilt as well as was stated above. Then there's that Jeep salvage yard in Ohio that would have them. I'll have to do the comparative shopping.

I do thank you all for the advice and help that you've given me in this quest.

One thing on my mind is that with this event, I'm not sure if I shouldn't part out the vehicle. I paid $3500 for it a couple of years ago. Its approaching 200,000 miles on the body and about 140,000 on the motor for which I paid $1200 including installation. I don't think the Jeep will make that back running ok so if its the head, I'll be upside down in it.
 
I paid $3500 for it a couple of years ago. Its approaching 200,000 miles on the body and about 140,000 on the motor for which I paid $1200 including installation. I don't think the Jeep will make that back running ok so if its the head, I'll be upside down in it.
Welcome to the automotive hobby. Seldomly do you get back what you put into them
 
A good XJ sells for $10,000 and the prices are going UP, not down. Just saying.....

BTW: I mean a GOOD XJ. Mine is a 2000. Leather front seats. A/C. Cruise. Aftermarket bluetooth radio. Roof Rack. No dents (has minor dings). Good carpets. No damage to interior. Minor rust (mostly under the bumper end on the passenger side, rear. OME lift, transfer case output shaft mod with good double cardan rear drive shaft, new calipers and brake cylinders, front disconnects, Wrangler tires, ready to go. For a jeep like mine....you will pay. People ask me if it is for sell and I tell them to start at 10 grand and go UP. It would cost me $45,000 to get a vehicle as good as the XJ I have. And even then it is debatable. The XJ market has flipped, like a lot of classic car markets. They are increasing in value if they are not rusted out. Recent barn find with 4,500 original miles is about to list at $15,000 and honestly....I have been thinking about buying it. A brand new XJ, smells new inside, for $15,000........... Where can you get MORE vehicle for the same price?

Just saying.
 
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