92 toyota 4WD 3.0 with NWOR headers. Catalitic converter plugged up back in august 08. had new system installed from headers back. magnaflow cat. Flowmaster 40 single inlet dual out. sounds great!!! . cat started rattling again in about 3 months had it replaced with another magnaflow cat. this one is starting to rattle already and muffler shop won't honor warrenty because they think something is wrong with engine - had my truck all day on their computer and good not find anything wrong. they think truck is running to rich. check engine light is not on or showing any codes. truck runs perfect and gets 17.5 miles per gallon city driving. Passed texas emissions test in oct. 08. no excessive amount of soot in tail pipe. 135,000 miles on truck. Ordered new cat from NWOR but need to know why this keeps happening. getting expensive!!!!.
HELP!!!!!!

 

Could you go, get it emission-tested to show that there is nothing wrong the the engine and get your warrantee honoured? If you pass, then they honour the warrantee (they have to), if you fail, then you get a clue as to what is destroying the cats.

 

truck passed emissions test in between Cat #2 and Cat #3. Muffler shop is also mech. shop. had truck all day ($100 ) could not find anything wrong. told me truck is running to cold ( 195 degrees ) - Oxygen sensor is in wrong spot. It's in same location as factory install ( in front of cat ).Told me my only solution was to take headers of and reinstall factory manifolds. will not warranty cat.

 

195 is fine for the temp- truck will go closed loop at 150-160 degrees.
did they pull the converter and stick a sniffer there to see what actually's coming out of the headers?

 

they said they scoped and scanned it. they thought is was running to rich before they scoped and scanned it. they really could;t find anything wrong but still would not honer the warranty. toyota dealer told me that if it was to rich or to lean my check engine light would be on. truck runs great, 17.5 around town with 31 in. rubber.

 

do a compression test I went through two cats before realizing a had a burnt valve causing unburned gas to go out exhaust and clog up my cat, I never had a check engine light either.

 

cat's are not plugging up, something is coming loose inside and thy are rattling. If i drive it to long it will break loose and totally plug up.

 

I'd threaten to sue for breech of contract. If they can't find anything wrong with the engine, and they seem to have the equipment to verify the operating condition of your engine and have made a reasonable effort to prove something is wrong with your engine (which they haven't substantiated), they'd likely be tossed out of court.
The other option is you take it in somewhere else and have everything tested on a dyno, down to EGT's, O2 and HC content at the header collector and then take that to court if nothing wrong is found with your engine. Then they get to pay for replacing the converter and your expenses on top of that.

Ass bad-a** as Texas is, they don't have any problems putting the screws to their own when they don't do right either.

 

Sounds like a cheap aftermarket converter to me. Try a different brand. If it was getting hot enough to break apart like that it would be glowing bright red. Have you bottomed it out & hit it?

 

I agree. They sound like they can't even determine what the problem is. They're throwing guesses around. They think it's running too rich, but you've had the dealer (the company that made the dreakin truck) verify that it wasn't running rich, and if it was you'd get an error code.

All i'd say is keep checking on the engine, do compression tests and get all the data you can, and then sue. If all they say is "something is wrong with the engine" and you can prove there is, in fact, nothing wrong with the enigne, then that's grounds for a lawsuit.

 

i agree. if your exhaust has run hot enough to break the cat, which it shouldnt have at only 195 degrees, then its a faulty set of cats. just be careful of who you take it to though. i took my 04 tacoma to the stealership after a check engine code right after installing a flowmaster. they told me i needed 2 o2 sensors, and 2 new cats totalling $2500. turned out my one o2 sensor bolt had snapped and was getting a false reading. i retapped the hole and put a new bolt in it. lights been out for 5 months. and thats "experienced technicians" from toyota. said that the cats were "definately" clogged. just goes to show that you cant always trust a proffesional. i'd just double check all the nuts and bolts and make sure everything is tight. a leaky exhaust can pull extra air in and make a cat hotter and burn up. thats what i would check first but a warranty is a warranty and they should honor it.

 

My cat from advanced auto did the same.No code on the internal system, but the snap on scan tool says "repair rich" . I get great mileage and plugs look good.Dealer says they cant help without a service ticket. Put a magnaflow on it and no problems

 

Get yourself comprehensive insurance and take it down to Austin and park it where the cat will be removed for free.

 

Ok. The two cat's that were rattling were magnaflow cat's that were $134 Cat's. I talked to NWOR who made the headers and bought the only high-flowcat they offer for $317. they seemed to think this might solve the problem. Truck is my daily ride to work and never gets off road to bottom out. NWOR (Northwest Off Road) thinks that only their cat or the oem one will work with their headers so i'm going to give it a try, its a lot cheaper than the oem one.