Catalytic Converter Confusion

Cheesy

Cheesy

TJ Enthusiast
Joined
Oct 1, 2019
Messages
707
Location
NE IL
After 16 years and 105,000 miles of creeping rust, it looks like it's time to replace the cats. PO341 code, replaced the suspect O2 sensor, B2 S2. Same code came back and when comparing the other three sensors on a real time graph the suspect O2 is kind of just lazing along. Just like it did before I replaced it. So, I need a new cat, and I may as well replace all three.

Here's were it gets interesting. The engine family on my rig is 5CRXT04.02N0, which is 50 state CARB compliant. I bought my rig used in Illannoy in 2010. I don't know if it has ever been in CA and it won't be as long as I own it. (Not hating on CA, just too damn far to drive in my Jeep) A 50 state cat set up runs in the neighborhood of $1500 to $2200 and that's doing the work myself. 49 state (now 47, I believe) runs from $250 to $700.

My strong sense of ethics and principals says to do right. My wallet is telling me to fuck your principals, get the $400 Flowmaster from Summit or put a piece of tape over the check engine light and be glad you live in a part of Illannoy the doesn't require emission testing. Yet.

Thoughts?
 
You don’t need to put a piece of tape over the check engine light. The cats and any codes related to removing them can be disabled via HPTuners MPVI2 software. Ask me how I know 😉
 
Cheesy said:
After 16 years and 105,000 miles of creeping rust, it looks like it's time to replace the cats. PO341 code, replaced the suspect O2 sensor, B2 S2. Same code came back and when comparing the other three sensors on a real time graph the suspect O2 is kind of just lazing along. Just like it did before I replaced it. So, I need a new cat, and I may as well replace all three.

Here's were it gets interesting. The engine family on my rig is 5CRXT04.02N0, which is 50 state CARB compliant. I bought my rig used in Illannoy in 2010. I don't know if it has ever been in CA and it won't be as long as I own it. (Not hating on CA, just too damn far to drive in my Jeep) A 50 state cat set up runs in the neighborhood of $1500 to $2200 and that's doing the work myself. 49 state (now 47, I believe) runs from $250 to $700.

My strong sense of ethics and principals says to do right. My wallet is telling me to fuck your principals, get the $400 Flowmaster from Summit or put a piece of tape over the check engine light and be glad you live in a part of Illannoy the doesn't require emission testing. Yet.

Thoughts?
Click to expand...
Research tells me the P0341 code is the cam sensor did you mistype. Rust on a cat is no reason to replace and what brand O2 sensors did you install.
 
Yeah, P0341 is not a cat code. Check the wiring harness for the Camshaft Position Sensor.
 
Amazon has the 3-cat set up for $263.95, It was $390 when I bought it a month ago. Pretty straightforward to do it yourself.

@Chris, don't know how to do the link so the forum gets credit.
 
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N757KF said:
Amazon has the 3-cat set up for $263.95, It was $390 when I bought it a month ago. Pretty straightforward to do it yourself.

@Chris, don't know how to do the link so the forum gets credit.
Click to expand...
Screenshot maybe? I can convert that to a link.
 
TJ4Jim said:
Research tells me the P0341 code is the cam sensor did you mistype. Rust on a cat is no reason to replace and what brand O2 sensors did you install.
Click to expand...
Yeah, I fat fingered it. PO431. Rust describes my LJ, not the cats, and NGK.
 
Cheesy said:
Yeah, I fat fingered it. PO431. Rust describes my LJ, not the cats, and NGK.
Click to expand...
Before replacing the cats, see if you can tighten the flange bolts. A 15mm ratchet wrench will reach all 4 bolts.

I currently have Eastern Catalytic cats on my ‘05 and they are absolute junk. The tubing is thin so the exhaust is loud and the hanger at the 3rd cat has ripped open the tubing, again because the tubing is so thin. Flowmaster appears to be the same design so I would expect similar issues. Magnaflow are more costly, but they also appear to be much better quality.
 
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I got that flowmaster 2049170 about six months ago for $225 on autohance.com. Has anyone else had problems keeping the 4 flange bolts tight? I've been fighting it for a while now, grade 8 bolts with a flat washer and lock washer threading into new factory J nuts. I tightened it up this weekend cold, drove it around to get it hot, then tightened it up again while hot, hoping that does it.

I'm pretty sure it's still leaking a bit, I think the flat, sharp cornered 3/8" plates they use for the flanges instead of the factory stamped steel ones with a matching taper to the flange is part of the problem. I tried getting the bolts pretty damn tight, and I think I can see these flanges bending around the flare in the pipe.

Something is killing my mileage, like 8-9mpg from my usual 13-14. It seems to get better for about a tank every time I tighten these flange bolts. Got all new NGK O2 sensors, iridium Autolite Plugs, and a new cam sensor after a recent code. Starting to wish I kept my old cats
 
AjRagno said:
Before replacing the cats, see if you can tighten the flange bolts. A 15mm ratchet wrench will reach all 4 bolts.

I currently have Eastern Catalytic cats on my ‘05 and they are absolute junk. The tubing is thin so the exhaust is loud and the hanger at the 3rd cat has ripped open the tubing, again because the tubing is so thin. Flowmaster appears to be the same design so I would expect similar issues. Magnaflow are more costly, but they also appear to be much better quality.
Click to expand...
Couldn't agree more. I'm going on my third replacement after stock and finally ponied up for magnaflow. Other cheaper options were worth about 10k miles for me... Not worth it for such a pain in the ass job. YMMV
 
Trevlaw said:
I got that flowmaster 2049170 about six months ago for $225 on autohance.com. Has anyone else had problems keeping the 4 flange bolts tight? I've been fighting it for a while now, grade 8 bolts with a flat washer and lock washer threading into new factory J nuts. I tightened it up this weekend cold, drove it around to get it hot, then tightened it up again while hot, hoping that does it.

I'm pretty sure it's still leaking a bit, I think the flat, sharp cornered 3/8" plates they use for the flanges instead of the factory stamped steel ones with a matching taper to the flange is part of the problem. I tried getting the bolts pretty damn tight, and I think I can see these flanges bending around the flare in the pipe.

Something is killing my mileage, like 8-9mpg from my usual 13-14. It seems to get better for about a tank every time I tighten these flange bolts. Got all new NGK O2 sensors, iridium Autolite Plugs, and a new cam sensor after a recent code. Starting to wish I kept my old cats
Click to expand...
Even my stock ones needed a tightening regularly, every 10-20k miles.

I had to go with a bolt and nut on my first cat replacement since the stock bolts stripped. Replaced the built and nut with the OEM clipon nuts and stock bolts. OEM hardware did seem to hold better than the replacement nut and bolt but also stripped on the latest removal. Looks like the prices have gone from about $2 a piece for the stock bolt and clipon nut to $17 a piece.

I'm picking up a welder shortly so I'll tack on some metal to the nut so I don't need to mess with a wrench on the nut at least....

Related, any of the cat replacements with the added hear shield on the upper cats (like the flowmaster appears to have) make this job of tightening the flange bolts 100% harder. Just always seems to be in the way for the angle needed to hit the bolts.
 
FarFire70 said:
Even my stock ones needed a tightening regularly, every 10-20k miles.

I had to go with a bolt and nut on my first cat replacement since the stock bolts stripped. Replaced the built and nut with the OEM clipon nuts and stock bolts. OEM hardware did seem to hold better than the replacement nut and bolt but also stripped on the latest removal. Looks like the prices have gone from about $2 a piece for the stock bolt and clipon nut to $17 a piece.

I'm picking up a welder shortly so I'll tack on some metal to the nut so I don't need to mess with a wrench on the nut at least....

Related, any of the cat replacements with the added hear shield on the upper cats (like the flowmaster appears to have) make this job of tightening the flange bolts 100% harder. Just always seems to be in the way for the angle needed to hit the bolts.
Click to expand...
I found a wobble extension to be extremely useful for that. Definitely a PITA though.
 
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N757KF said:
I found a wobble extension to be extremely useful for that. Definitely a PITA though.
Click to expand...
Agreed! Also using 3/8" socket and then adapted up to 1/2" for the impact gun once you're below the cat gives more maneuver room at the socket.
 
FarFire70 said:
Even my stock ones needed a tightening regularly, every 10-20k miles.

I had to go with a bolt and nut on my first cat replacement since the stock bolts stripped. Replaced the built and nut with the OEM clipon nuts and stock bolts. OEM hardware did seem to hold better than the replacement nut and bolt but also stripped on the latest removal. Looks like the prices have gone from about $2 a piece for the stock bolt and clipon nut to $17 a piece.

I'm picking up a welder shortly so I'll tack on some metal to the nut so I don't need to mess with a wrench on the nut at least....

Related, any of the cat replacements with the added hear shield on the upper cats (like the flowmaster appears to have) make this job of tightening the flange bolts 100% harder. Just always seems to be in the way for the angle needed to hit the bolts.
Click to expand...
Yeah I tried using a nut and bolt one when my factory clip on nuts broke, literally took me hours to tighten everything.

I've been using these now, 6506546AA, only like $5 for a pack of four. I was thinking of maybe getting some strong serrated flange bolts to try next.

I usually turn the wheel all the way to the right and I can slip in between the frame and the tire, then with the rubber inner fender removed I can get my arm up between the frame and sheet metal to use a straight ratchet wrench on all of the bolts
 
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