WJCO's Build Thread, 1999 WJ

Slimebones

Slimebones

Active Member
Yeah, diagnosing a problem is the hard part. So many things affecting each other anymore. Your cause and affect logic will eventually get to the base of this though. I have faith in you!
 
WJCO

WJCO

Meme King
I hope so, too. Luckily if it doesn't get fixed, I can live with it. It's not like it's overheating where I can't drive it.
The biggest thing that sucks is stop and go traffic or waiting to pick the kids up at school. As soon as the temps rise at idle, it causes the high side of the AC system to increase to an unsafe level and shuts down the compressor. So no AC while idling. That's the hardest thing to deal with.
 
WJCO

WJCO

Meme King
USMC Wrangler said:
I applaud your perseverance with this. Isn’t this your second summer troubleshooting? I too hope it’s the cat! If not, I’m with Ddays. LS swap time! [emoji6]
Click to expand...

Yep. 2nd summer for this shit. The summer prior to that and others before, this issue didn't exist.

Jsouder53 said:
No AC while idling is the worst, especially when there is no breeze, so windows down doesn’t help... Good thing you are not in Florida, my work truck is without AC and it’s unbearable at times.
Click to expand...

Very little humidity here, so that does help. But yes, it still sucks with no AC.
 
MSJKU11

MSJKU11

Caught the Bug
So discouraging spending money to fix a problem to only find out, it didn't fix the problem. Hoping it's your cat and if not you'll find the problem eventually.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 
WJCO

WJCO

Meme King
fiend said:
Water pump failing?
Click to expand...

I've installed two of them, lol. Got the 2nd one just assuming the possibility that I got a defective one. Both do have plastic impellers. I did the same with the fan clutch. Being that the problem goes away when I rev it up, I looked at both of those as an option.

MSJKU11 said:
So discouraging spending money to fix a problem to only find out, it didn't fix the problem. Hoping it's your cat and if not you'll find the problem eventually.

Sent from my SAMSUNG-SM-G930A using Tapatalk
Click to expand...

No kidding. And I hate throwing parts at a problem but this one really has me stumped.
 
WJCO

WJCO

Meme King
So I got the OEM cat back on.

IMG_20180528_161727_809.jpg

Here's what it looked like with the aftermarket cat:

IMG_20180528_164907_185.jpg

Here's the OEM one on top and aftermarket on the bottom. The OEM one has almost twice the volume of catalyst material compared to the aftermarket one.

IMG_20180528_161639_870.jpg

I'm trying not to get my hopes up, but I noticed 3 things right away:

When I started the Jeep, the intake suction was WAY louder. It wasn't even something I was prepared to listen to. It threw me off guard and I thought I had something leaking up front.

Test driving it, it had a ton more power. Very noticeable. Even with the AC on, the engine performed much stronger. I was really surprised but happy.

When shutting it off, there used to be this hissing air sound for a couple of seconds. That's not there anymore. That's another thing that caught me off guard. There was just this sound that I've gotten used to for awhile and when it wasn't there, my attention was drawn to it.

I installed this aftermarket cat in January of 2017. If it truly was the culprit from the beginning, I'm surprised I didn't notice the power loss back then. It also may have been working just fine until the water crossings on the trail I did in July that year and then the cold water fucked it up. Hard to say. I will say, when this Jeep is fully loaded with family and gear, I wish it had more power in the mountains. The main reason I changed the cat originally was ground clearance. I've hit the OEM cat on rocks before because it's a huge cat. Maybe there's a reason that Jeep made it that big though.
If it doesn't fix my issue, I can't do anymore. There is probably a crack internally in the block and I'll just leave it. I really doubt that as it passed a block test, the plugs don't have coolant residue, no oil/coolant intermix, etc. But I have no more options at this point.
It's 75F here today, so I'll have to test it another day.
 
Last edited:
notnalc68

notnalc68

That dude from Mississippi
WJCO said:
So I got the OEM cat back on.

View attachment 302510

Here's the OEM one on top and aftermarket on the bottom. The OEM one has almost twice the volume of catalyst material compared to the aftermarket one.

View attachment 302511

I'm trying not to get my hopes up, but I noticed 3 things right away:

When I started the Jeep, the intake suction was WAY louder. It wasn't even something I was prepared to listen to. It threw me off guard and I thought I had something leaking up front.

Test driving it, it had a ton more power. Very noticeable. Even with the AC on, the engine performed much stronger. I was really surprised but happy.

When shutting it off, there used to be this hissing air sound for a couple of seconds. That's not there anymore. That's another thing that caught me off guard. There was just this sound that I've gotten used to for awhile and when it wasn't there, my attention was drawn to it.

I installed this aftermarket cat in January of 2017. If it truly was the culprit from the beginning, I'm surprised I didn't notice the power loss back then. It also may have been working just fine until the water crossings on the trail I did in July that year and then the cold water fucked it up. Hard to say. I will say, when this Jeep is fully loaded with family and gear, I wish it had more power in the mountains. The main reason I changed the cat originally was ground clearance. I've hit the OEM cat on rocks before because it's a huge cat. Maybe there's a reason that Jeep made it that big though.
If it doesn't fix my issue, I can't do anymore. There is probably a crack internally in the block and I'll just leave it. I really doubt that as it passed a block test, the plugs don't have coolant residue, no oil/coolant intermix, etc. But I have no more options at this point.
It's 75F here today, so I'll have to test it another day.
Click to expand...

If that’s what it is, that’s nuts. Who would have thought that?


Sent from my iPhone using WAYALIFE mobile app
 
WJCO

WJCO

Meme King
notnalc68 said:
If that’s what it is, that’s nuts. Who would have thought that?


Sent from my iPhone using WAYALIFE mobile app
Click to expand...

The only reason I even looked in this direction was a few weekends ago after I got towed from the mountains. It was my air intake that collapsed but it felt just like a bad cat. I had no power at all. Prior to finding out the air intake was the problem I almost changed the cat back to OEM. It felt like the engine wasn't breathing. I found several stories online of jeeps with fucked up cats after water crossings. The cold water hits the hot cat and cracks the catalytic material and it either moves and plugs the exhaust or it starts melting into a blob. I also found info that a plugged cat can cause engine heat to increase due to excessive back pressure. So it just stuck in my mind and I also realized that since installing that aftermarket cat, I only did one trail before the symptom showed itself and the day of that trail it was cold and wet outside so the problem wouldn't have shown up that day anyways. I'm really hoping this is it.
 
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