shaner164

Hey guys,
Does anyone know what are the most common symptoms of a catalytic converter needing replaced?
Thanks,
shaner

Belto

if you hit them from underneath and there is something lose , replace it..

89xjgrey

A lot of times, a burnt converter will smell like sulfer, or rotten eggs. If you have access to a live data scanner, check both 02 sensor readings. If they change identically, converter is bad...or like Belto said, if it is rattling internally, it is bad.

finneys98xj

If you dont have much power and the motor isn't knocking it may be stopped up.

UNCC_99XJ

A lot of times you can hear the knocking/rattling driving around town...as is the case on my friend's 98 right now.

Or as was my case, your check engine light can come on about 5 times each week showing o2 sensor #2 high voltage (since that sensor is only there to monitor the converter anyways). Drove it for 2 years like that before I finally narrowed it down to a faulty converter and not a faulty sensor.

okcjeeper

lol I can hear mine rattle when I drive around..it's funny as hell but I need a new one just errm haven't ordered one yet..

Howler_GT

IF your factory converter is more than 8yrs old, it is mostlikely dead.
The OEM units were known for failure.

Causing poor performance and awful gas mileage.
And most times a nasty loud rattling.

Mine in the 94 was that way. Thought the flexplate was loose, or worse a bad connecting rod.

89xjgrey

If I recall, there is a federally mandated warranty on converters that are bad with less than 80,000 miles and 8 years old...

shaner164

Thanks guys, I hear a rattle every now and then, and it seems like the power has depleted some since I have owned it.( few months ) also the gas mileage is awful, I'm only getting at best 12 to 13 mpg in the city ( while driving like grandma ) ,which is what I drive mostly. I do see a bit better mpg on the hwy, I got it up to 18 mpg spit between city/ hwy. I had the computer checked and there were no error codes that showed up. I have changed spark plugs and wires, air filter, belt,oil and had an injector flush done. So a C.C. will be my next item to change .Hopefully it'll help increase my mpg. Can anyone suggest a brand/type thats good?
Thanks

JeepersCreepers

My jeep has **** poor gas mileage. So can my converter be bad?

UNCC_99XJ

Maybe....but at 16 years old, your oxygen sensor (number 1) could probably stand to be replaced. How many miles do you have?

As for what brand of converter, I really like magnaflow....didn't really notice a performance gain per say, but it sure does sound sweet matched up with my flowmaster.

JeepersCreepers

i have 188,000 miles on my jeep.

JeepersCreepers

ya i just looked at my o2 sensor and it looks to be original.

Blackburn

A clogged converter will also create excessive heat enough heat to make your floor hot above it.
My 98 TJ was covered by a catalytic recall caused by the guts rattling and loose. This however didn't seem to have an effect on performance just annoying sound and I'm sure all the exhaust went around the filtering material instead of through it.

JeepersCreepers

ya i think my cat is still good. i noticed when i was changing my o2 sensors that the exhaust system has been replaced. but also noticed that theres no after cat o2. someone must have taken it off. im guessing thats whats giving me terrible gas mileage.