I had one of the catalytic conv go bad on my Silverado and I was informed it’s illegal not to have one. So if it’s illegal to bypass it, what can be done other then replacing it ? Thanks
17’ Mako
16’ Alumacraft
“test pipe”. 
http://www.siliconeintakes.com/dsm-intercooler-piping/high-flow-cat-p-572.html
I know “someone” who supposedly took a plasma cutter and cut three legs of a rectangle and bent the flap down then removed (gutted it) all the material in the cat. Then bent back into shape and welded back. Did actually see a gas mileage improvement. The stuff breaks up really easy, it’s like a honeycomb porcelain with precious metals in it… platinum, palladium and rhodium.
Biggest issue is the year of your truck some are more sensitive to activating the CEL due to having an O2 sensor before and after the cat. Many programmers are available to eliminate this worry.
There has been talk of making SC residents have to pass an emissions test to stay road worthy, but I doubt we will see it happen anytime soon.
I’ll say this, I would never buy a cat if I needed one out of warranty.
i agree with fred. if youre out of warranty, gut it or just cut it out. i was pulled over alot when i was younger. never had cats on any of my cars, and never got checked. fred is also right, it very well may cause a CEL. they also sell dummy O2 sensors that will replace your rear O2 (which is the one that senses whether or not your CATs are working correctly). That will keeep your CEL from coming on. you will need to keep your front O2 sensor working good. without it, your ECU wont be able to properly adjust your mixture ratio with your fuel injectors.
Proline 201WA
Aloha 24ft pontoon (LooneyToon)
Old Town stern with 7.5 johnson
If you lack the tools and mechanical ability to do this yourself ,I suggest you ask some of your friends if they can vouch for you down at the local neighborhood garage.If I knew you personally,I could make your problem go away with one phone call.Everyone needs to have a guy for things such as this.Dealerships are alright for some things but you need to build some relationships with a few local guys, capisce.Good luck
Back in school my 87 S10 Blazer had a cat that was clogged up and I can still remember what the glowing red cherry converter looked like. I knew a lot of the local mechanics and they took it out back and welded a straight pipe in. Problem gone.
I actually think I have a clocked cat on my diesel Mercedes now. Not sure what I am going to do. Might see if it can be rammed clean and put back on. I imagine a Merc cat is pricey.
“Wailord”
1979 17’ Montauk
90 Johnson
Wilderness Ride 115
quote:
Originally posted by GeronimoBack in school my 87 S10 Blazer had a cat that was clogged up and I can still remember what the glowing red cherry converter looked like. I knew a lot of the local mechanics and they took it out back and welded a straight pipe in. Problem gone.
I actually think I have a clocked cat on my diesel Mercedes now. Not sure what I am going to do. Might see if it can be rammed clean and put back on. I imagine a Merc cat is pricey.
“Wailord”
1979 17’ Montauk
90 JohnsonWilderness Ride 115
No ramming clean. If it is faced plugged replacement is needed or if clogged and taken to a dealer that can clean one it is basically compressed air blowing off the soot… if possible. So with that said you can pull it off yourself and take an air blower and clean it. The soot is so clean it is a non biological hazard.
We bought a $60,000 dollar unit to clean DPF’s (Diesel particulate filters)… A catalytic converter on a diesel engine. All it is is a big sealed unit that blows compressed air through the dpf and vacuums it out. the waste material collected can be legally put in a dumpster . If it all blows out it is given back to the customer, if it has had coolant or other crap run out the exhaust and can’t be cleaned customer is told to buy a new one.
What year is the Mercedes? Is it pre DEF meaning tier 4 interim or lower? In a Diesel the biggest issue with face plating is coolant entering the exhaust. I’d say 90% chance of a bad EGR cooler.
Now that you say that, my low coolant light did just come on telling me to top it off. I smell more diesel now, and the exhaust has a weird sound. Almost like there is a leak somewhere, or just a different sound in general. I figured it was the cat backed up because when pushed hard at 3500-4500 rpm the ECU will kick off a few cylinders but not throw a CEL. From what I have read, the engine reads it as a misfire on certain cylinders and it shuts some down to save any damage. Folks have said clogged cats cause backpressure that gives a misfire under heavy load and could also just be an O2 sensor. It feel like it is the cat and possibly the EGR valve you speak of.
It’s a 2008 Mercedes 320 V6. No blue DEF so not sure of what other regulations it has. I know it had so crappy vein system on the manifolds to redirect exhaust gas to be burnt, but not sure of the emissions beyond that. It’s been very low odor since Imhave has it never smelled like a diesel before now.
“Wailord”
1979 17’ Montauk
90 Johnson
Wilderness Ride 115
Not sure how your mercedes is set up but What I’ve seen a good bit is an internal leak in the egr. It runs engine coolant through it to cool the exhaust getting sent back to the intake to be reburned. Hence the “less” power. Your engine is not getting a clean air charge.
In the past this was an issue with the “black smoke” from inefficient injection systems. Today without all the fancy Exhaust treatment systems diesels don’t “black smoke” (Unless you drastically change the tune, injectors, turbo, and fuel pump to supply all the needed fuel). Tier 4 final running DEF is the EPA making love to the Country.
I have seen a tier 4 final engine with emissions removed pass an emissions test. Detroit Diesel did a 10,000 mile test proving this.
Want something really neat. Look at a New Chevy diesel truck’s exhaust tip (I think ford does it too?) What you will see is a 12" extension with holes in it that creates a venturi drawing in fresh air. Put a probe behind that point and your emissions level will be higher. Just fooling emissions. No different than diluting a good bourbon drink with water. Add more fresh air and your emissions decrease.
Remember the old air pumps on the late 70’s and into early 90’s cars and trucks? All it did was pump fresh air into the exhaust. Another huge EPA scam.
If I put an electronic y pipe ahead of the cat that’s bad would that make the check engine light go out ( it’s on right now because of the O2 sensor) ???
17’ Mako
16’ Alumacraft
electronic Y pipe? for what? if your CAT is bad, that’s why your O2 sensor is throwing a code. assuming it’s a bank 2 code.
Proline 201WA
Aloha 24ft pontoon (LooneyToon)
Old Town stern with 7.5 johnson
Knowing a local mechanic is one of the best things you can have going for you. My best friend since middle school runs a shop up here in town and will do anything I need and knows what you can and can’t do to get around things. Knowing one first hand will get you much more knowledge than someone who just walks in off the street
Sea Pro sv2100/ Yamaha 150