Catalytic Converters.

kman101 · #1 (**permalink**) 10-31-2007, 11:01 PM

I read on another thread that a cat may reduce the gas mileage of cars. i have a bronco 2 with the stock engine and tranny. i get about 16 to 17 mpg. and it feels real slugish sometimes. i guess my question is that if its legal to gut or not have a cat on my bronco. Thanks.

85e150six4mtod · #2 (**permalink**) 10-31-2007, 11:20 PM

Your problems could be a number of things, including a partially clogged cat.

Do you have smog inspections for your vehicle in your state? If so, you will not pass w/o a cat.

It's not legal to remove or disable the cat. But unless you have inspections no one is going to know.

There are some ways to determine if the cat is clogged by measuring pressure in the exhaust at the oxygen sensor, perhaps an engine vacuum test, maybe a couple of others. If you can disconnect it you can visually inspect it and see how your rig runs without it.

But, there are a number of things that cause performance to go downhill and high miles/age are part of it.

Have you done a compression test? Check for vacuum leaks? Basic stuff along with checking the cat.

Good luck.

rebocardo · #3 (**permalink**) 11-01-2007, 12:20 AM

> if the cat is clogged by measuring pressure in the exhaust at the oxygen sensor

That works with vehicles with an O2 after the cat, a BII has a single one before the cat.

The automatics can be sluggish, 16-18 mpg is normal with the automatic. You can adjust the cables with lead weights or zip ties. I posted about that a few years ago if you do a search.

kman101 · #4 (**permalink**) 11-01-2007, 10:45 PM

all sounds good. and i took the cat off it ran much better. i LOVE 2ND GEAR (i have a 5 speed). i put a pipe in for now. i got a universal cat cuz i dont need to pass somg tests. i dont know about mpg yet but i know now it really moves. thanks guys i really appreciate it.

85e150six4mtod · #5 (**permalink**) 11-02-2007, 12:27 AM

Quote:

Originally Posted by rebocardo

> if the cat is clogged by measuring pressure in the exhaust at the oxygen sensor

That works with vehicles with an O2 after the cat, a BII has a single one before the cat.

The automatics can be sluggish, 16-18 mpg is normal with the automatic. You can adjust the cables with lead weights or zip ties. I posted about that a few years ago if you do a search.

Wouldn't the before the cat plug be where you'd find high pressure vs. what's coming out the pipe?

Anyway, it sounds like it was a clogged/melted cat.