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03 TJ losing power and dying

k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
I've Google'd and read anything from O2 sensors, cracked manifolds, plugged CAT, and I'm hoping someone can help me narrow it down.

A few months back it started revving intermittently, so I replaced the TPS this morning...it also over the past 6 months or so, started losing coolant, but for the life of me, I can't see where from (the only time I actively hear pressure escaping is occasionally after driving, I hear it blowing bubbles in the coolant overflow)

The check engine light has come on a few times, but goes away shortly after, so I didn't think much of it...did the self check this morning, after replacing the TPS and it is showing no codes, goes straight to "done"

Any help would be GREATLY appreciated!
 
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k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
Fair enough...I forget I'm a day ahead...just saw tons of activity on dozens of other posts, so...

On the bright side, I think I've tracked down my coolant leak...
 

BeavisTJ

Member
Sep 27, 2018
80
Queensland, Australia
Can you explain what kind of symptoms you're having? I have a feeling they are going to be like mine.


Im still trying to find a solution for my Jeep. Mechanic is going to look at it this week. Trying not to just throw parts at it.
 

GPSsignallost

Member
Jan 7, 2019
26
US
So first off im no expert i just have a high milage TJ.
First thing we need to know is whats the temp gauge doing? When driving and then when stopped. It should read slightly left of center and from my experience it shoulnt fluctuate much. When my rad failed the gauge would creep above 210 in traffic and then go back to normal when I started driving.
If u hear bubbling in the overflow i would check the radiator cap. reason being its possible that the system isnt under the correct pressure cuz the cap failed. 207 degrees under correct pressure = no bubbling 207 degrees at atmospheric pressure = bubbling. The other thing to check is the top of the radiator for cracks. Thats what happened to mine .Not a catastrophic failure but i had to add fluid because it was all bubbling into the overflow . I could only see the crack when the engine was running and i could see a slight foaming bubbles on the crack.

Maybe if u can answer these questions others may chime in with more things to check. Good luck!
 

Goatman

TJ Enthusiast
Apr 23, 2019
507
Upstate NY
Fairly common for head gasket leaks coolant into combustion chamber. If it's bad you should get a sweet smell from the exhaust. Kind of a sicky sweet. On the intake stroke the neg. pressure of the piston going down will draw the coolant in. Then on the compression stroke it will blow air into the cooling system. Sometimes it does one, sometimes it does both. Anytime an engine loses power I look at fuel system first. Think filters, pinched hoses, poor fuel pressure, etc. The coolant issue indicates a head gasket issue so perhaps the power issue is connected to that.
 
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k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
BeavisTJ - mine isn't bucking or sputtering/running rough...just loses power like you're going uphill and need to downshift, and when you push the clutch in and stop, it dies, unless you get on the gas...I hear you, about not wanting to throw parts at it...

GPSsignallost - I have suspected the cap, due to the bubbling, but don't have the tools to pressure test anything...although while lying under the front while idling today, I spotted water slowly dribbling off the bottom of the radiator, on the engine-side. Will replace the cap when I swap the radiator.

Goatman - as mentioned, I believe the coolant leak to be sorted 🤞 It has been an issue for several months, while the weird power loss has only started happening this past weekend. Fuel system sounds like as good a place to start as any...I had to replace the fuel pump in my old Cherokee back home a couple times so I'm hoping the curse hasn't followed me down under...
 

twistedlv

TJ Enthusiast
Supporting Member
May 26, 2018
263
Las Vegas
BeavisTJ - mine isn't bucking or sputtering/running rough...just loses power like you're going uphill and need to downshift, and when you push the clutch in and stop, it dies, unless you get on the gas...I hear you, about not wanting to throw parts at it...

GPSsignallost - I have suspected the cap, due to the bubbling, but don't have the tools to pressure test anything...although while lying under the front while idling today, I spotted water slowly dribbling off the bottom of the radiator, on the engine-side. Will replace the cap when I swap the radiator.

Goatman - as mentioned, I believe the coolant leak to be sorted 🤞 It has been an issue for several months, while the weird power loss has only started happening this past weekend. Fuel system sounds like as good a place to start as any...I had to replace the fuel pump in my old Cherokee back home a couple times so I'm hoping the curse hasn't followed me down under...
I'd lean toward plugged exhaust. Low fuel pressure would definitely throw a code. How do the plugs look, and what kind of plugs are you running? TJ's seem to be very particular about which plugs they like.
 
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k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
"I haven't checked the plugs" he replied sheepishly...

I told myself several times "You should probably have a look at the plugs" but mostly up to this point I've been cursing and stressing that it's something major...I was originally thinking plugged CAT (due to a Google search) but the weather has been crap and raining steady the bulk of the time since it started having problems, which has hampered things a little (I seem to have excuses for everything 😒)

Sure would feel like an idiot if it was something as simple as plugs...
 

dbbd1

go away...
Supporting Member
Jan 4, 2019
776
Oregon
You can remove the O2 sensors upstream of the cat and run it. It will throw a code but see if it runs better. If it does, you know it's the cat.
 

Goatman

TJ Enthusiast
Apr 23, 2019
507
Upstate NY
You could also throw some stuff in the gas tank tha is suppose to clean up injectors and cats. Some say the Techron brand is the best stuff. Its "cheap" and easy.
 
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k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
What kind of fuel do you guys get down there? Does the government love ethanol, like here in the US?
Yep...they have the same flavors here as we have back home 😁

You could also throw some stuff in the gas tank tha is suppose to clean up injectors and cats. Some say the Techron brand is the best stuff. Its "cheap" and easy.
Couldn't hurt, huh?

And easier than cutting a hole in the cat and patching it with a soup can...
😂😂😂 I'm trying dor cheap/easy...but not quite THAT ghetto 😂😂😂
 
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k0m0d067

Member
Jun 9, 2019
31
Victoria Australia
So O2 sensor out...drove it around for maybe 10 minutes (not really enough to tell anything) Sounds hilarious! 😁

Got code 0031 and 0132 (does that sound right? Suppose I should look it up 😁)

Will drive it a bit more after work tomorrow...too dark to risk breaking down at the moment...off early on Fridays, gives me more daylight to test it with...
 

Goatman

TJ Enthusiast
Apr 23, 2019
507
Upstate NY
You could just disconnect the O2's from the harness instead of actually pulling them. Easter and you wont break anything really determined to stayrusted put.😁
 
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