How to check for clogged Cat.Converters??

[Kdubslugga]

My friend is getting crappy gas mileage. It has to be the o2 sensors or the converters, ive checked everything else. i tell him to just get an off road h pipe, but for some odd reason he doesnt want to get one. Anyways is there anyway to tell for sure if the coverters are clogged, if so how do i go about doing it?

 

[Black Sun 5.0]

I had a similar concern about my cats, the shop I take the car to had to check the exhaust pressure. I recently spoke to mechanic that claimed if the cats are gone (broke up over time), this could negatively impact mileage also. Did you run codes to see if the O2's are bad? I've been fighting a severe drop in gas mileage in my car for about a year and a half now with no success. Good luck.

 

[Black331Stang]

i also have a massive drop in gas mileage. I think its this long island air
Black Sun- do u know anywhere where i can get an inspection without cats and stuff??

 

[mousetrapcar]

you can just look down into the h-pipe with a flashlight and see how bad it looks. you probably need a clean h-pipe so you can compare but my mechanic showed me the clogged pores. they became clogged because my engine is burning oil. just so you guys know also when my cats went bad they were making a rattling sound, almost like a marble in a tin can that i thought was the engine.

i don't mean to jack your thread but i have a question concerning cats, how exactly do you gut the cats? the mechanic gutted only the pre-cats on my car and i figured since i have to replace the whole h-pipe to pass smog next year, i might as well gut the other two. thanks

 

[2[H]4U]

does it backfire ever?

 

[drgn5.0]

knock on cats with a rubber mallet, if you hear stuff bouncing around, they are bad.

 

[Black Sun 5.0]

Inspection w/o cats on L.I.? Eh, to reveal such a thing could be a bad thing, don't ya' think? Yeah, my cats sounded like the marble that was described, but it then went away. I assume the cat just broke up. I don't know if this would affect gas mileage, though. Avoid the BBK stuff. I got their catted
H-pipe and it broke up in little over a year. Black331Stang, if you sell me that solar deflector on your ride, I might be pursuaded to tell you the info you request.

 

[Mikey1968]

If you got the pre-cats done, all you have to do to get the back cats gutted is to simply unbolt the pipes. Run a long rod, screw driver or crow bar into the back and hit it with a hammer into the cats. Nail it a few times then start the car and rev. Crap will fly out. Do this over and over until all is gone. It's really worth your time to buy a good off-road pipe like MAC, though.

What do you guys consider bad mileage? I have a stock 86 Capri with 222,000 miles and still get 22 mpg. I had to pull off my off-road and go with 91 cats to pass smog in Kommifornia. The 22 mpg is with these cats. 86s were recalled due to the marble in a can problem. That's what got me to get rid of them. The 91 cats seem OK. Hmmmm...I did say "stock," I did pull off the air silencer and put in a K&N and put in Midas turbo mufflers. That will help some but I do have a stock AOD.