The Grackle

[PhullD]

My exhaust has been pretty smelly for a while now and decided I'd finally replace the primary cats and check out the rest of the exhaust piping since it's getting up there in age. I pulled of the secondaries ( I gutted those years ago in case the primaries ever broke up) and ran my scope camera up towards the engine, after a few seconds I saw the A/F sensor on my screen. I backed up and checked again and confirmed it, the passenger side cat is completely missing. I ran the scope down towards the muffler and didn't see anything so its remains must be packed inside the muffler somewhere.

I have absolutely no idea when this happened, I've never had any misfires or lost power issues so when it broke up it must have just exploded. Thankfully the secondaries were removed so the pieces could flow away from the engine and not completely clog up the exhaust. I haven't noticed any significant oil burn so the engine might have been spared, but my next step is to do a compression test to make sure before I spend any money on exhaust components. I always knew this was risk and I was willing to take it by cheating the codes with spacers on the sensors, I'm mostly just surprised that it happened without me noticing anything.

If the compression numbers check out I'm probably going to have to do both cats plus a cat back system since the muffler is now filled with cat pieces. What hurts the most by far is that I finally decided to do the cats and my 250 dollar core refund exploded and ran out the back haha.

I hope bits didn't go into your engine. A friend of mine had that happen on a 1st gen and the motor was toast. On the bright side if the engine is ok you can look forward to a sweet new exhaust. I want to redo the clutch and the exhaust but can't justify the cost since they are still ok, but I look forward to the day they both go lol!

 

[SledheadX]

I hope bits didn't go into your engine. A friend of mine had that happen on a 1st gen and the motor was toast. On the bright side if the engine is ok you can look forward to a sweet new exhaust. I want to redo the clutch and the exhaust but can't justify the cost since they are still ok, but I look forward to the day they both go lol!

Interesting hearing someone else saying that. I too have been waiting… 4 years with my new cat back AFE exhaust in my shed for the now 50k miles since purchase for my clutch to melt. Now I should probably be concerned that my cats be the first to explode In this series of maintenance events. I just don’t look forward to the bill. I too hope the motor is ok.

 

[General_Tarfun]

I hope bits didn't go into your engine. A friend of mine had that happen on a 1st gen and the motor was toast. On the bright side if the engine is ok you can look forward to a sweet new exhaust. I want to redo the clutch and the exhaust but can't justify the cost since they are still ok, but I look forward to the day they both go lol!

Fingers crossed on that one. The inside of the pipe where the cat used to be is weirdly clean and smooth like it was never there to begin with, almost like the entire thing unseated from the sides and pushed out in one go. I'm hopeful the engine is ok because the exhaust piping on that bank from the rear cat to the manifold is fairly clean and I can see clean metal. No visible oil burn residue coating the pipe but we'll see what the compression test tells me.

If the numbers are reasonable for a motor with 220k a new exhaust is definitely in my future, I'm a little worried about the muffler being clogged up with pieces but when I tried to remove it all the sections that are supposed to be removable are rusted together with some kind of super strength bond. If I end up replacing it I'm definitely cutting it open to see where the cat chunks landed.

 

[General_Tarfun]

Got it all back together and passed emissions. I ended up replacing the rear cat on Bank 1 with a Walker 140 dollar special and installing a no-weld Glowshift O2 sensor relocated on the pipe after the cat to move the rear sensor backwards behind the new cat. I extended the wires on the rear sensor and put on a longer fiberglass heat tubing to insulate it all. No broken studs either, I soaked everything with CRC's Knock er Loose spray and let it soak for an hour and then slowly worked the nuts back and forth until they came out smoothly. That stuff works better than I expected so I'll be keeping that in my toolbox going forward.

No leaks so far, I used plenty of copper exhaust gasket maker in addition to the normal gaskets, that stuff works pretty well. In the primary cat I saw a spiral metal thing that I think used to hold the cat so I cut that out and removed but that was the only surprise. The muffler piping is rusted together pretty well so I couldn't get that out but that will be next up on the list along with a compression test, but I have a feeling that the cats been missing for a while now so I might be in the clear.

Sidenote, I didn't end up needing to use it but I found that if you split the sensor wire from the bank that has a working cat and connected it to the truck side harness for the non-working side (so one sensor is sending signal to both inputs), the X accepts the signal and passes the emissions self test that goes on.

 

[General_Tarfun]

The X has been running great since the exhaust work last month. So far the gas mileage has slightly improved by a couple mpg on the highway which is interesting, I'll see if that holds up over time because I don't see why unless the engine really didn't like one bank having more back pressure than the other. Next up is the rear main seal, it's gone from a slow seep to droplets appearing on the underside plus the compression test. I'm getting married in two weeks and that's really been getting in the way of my projects haha.