Is my CAT leaking or clogged?

willys5555 · #1 10-16-2009, 07:53 PM

on my way home the truck started shaking and check engine light came on. at first i thought it was something like my mis-fire but it was much worse. so i came home and did the normal checks i do for my continuous misfire and everything checked out fine. one thing i did notice while driving is my exhaust was louder and i lost a lot of power. so while i had it here at the house, i got under and listened and i can hear noise by the cat. but i cant tell if it is leaking or clogged...either way i think thats the problem. does this sound right?

i also un did my battery and let it reset the check engine light and then went on a drive. it isnt as rough as it was before and the check engine light isnt on any more. but the sound is still there and it still feels slugish.

so my next question is, my friend has 2 magnaflow high flow cats that he will sell me...is it legal and safe for my truck to put one on each side? if i understand the laws right, you only need one on each side...correct? i have a 97 so i have 2 cats on each side. also, will it mess with my o2 sensors or anything having only 1 cat on each side?

please let me know what yall think of this as i need to get it fixed this weekend.

Thanks

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migdaddy · #2 10-16-2009, 10:09 PM

Crawl under your truck and check to see how many cats you have. You should have 2 pre cats and 2 rear cats. Most likely your pre cats are blown. You can put 2 high flows on in replcement of the pre's. If it isn't your pre cat and it is ur rer cats make sure your friends cats will fit. Also get a part number on the cats ad make sure they are the right ones and ur not putting on high flow pre's in ur rear cat location. If it's your pre cats you won't worry about the o2 sensor but if it's the rear cats make sure you put the o2 sense after the new cats. But first check to see how many cat u have and where the 02 sensor is. Most likely it is in the cat itself

willys5555 · #3 10-16-2009, 11:13 PM

yes i have 2 pre and 2 rear. but i believe it is my rear one...that is where the sound appears to come from.

also, my friend has the exact same truck...only difference is his is a 5.4 and mine is 4.6. but both are 97s...will that make a difference? the way he had it set up was the high flows replaced both the pre and rear cats. is that a correct way to do it?

migdaddy · #4 10-17-2009, 01:43 AM

your in texas, i would check with your local shop and see what regulations you have. if its ok, then you can replace all 4 of your cats with 2 high flows. otherwise, you can just replace your 2 rear with the 2 high flows, and keep the pre cats. Also, sell whatever cats you take off to a salvage or scrap. youll be able to get around 200 bucks for them since your truck is almost 13 years old.

DarrenWS6 · #5 10-17-2009, 01:42 PM

I know Texas permits you to have atleast 1 cat per engine bank so yes you can legally change to just two hi-flow cats.

migdaddy · #6 10-17-2009, 03:41 PM

Thank you Governor of Texas

willys5555 · #7 10-17-2009, 10:52 PM

will having only the 2 high flow cats cause me any problems with my check engine light? where do the o2 sensors have to be at? as it is my understanding, the back 02 sensors just go right after the CATS correct? so is that all i need to do to keep my truck running correctly? i dont want any adverse problems caused by this.

thank you so much for your help.

migdaddy · #8 10-17-2009, 11:33 PM

your o2 sensors need to be welded in after the new cats, correct. your on it. you dont even need any help haha

willys5555 · #9 10-18-2009, 01:21 AM

well i have read some on here about the place of the o2 sensors...so i pretty much knew that one but through it in there just to clerify after my other questions. the point on this thread was if clogged cat was my problem (although i am pretty sure it just rusted out and is leaking as i am hearing a noise that sounds like air escaping) and if it is legal to use a single cat and if i can use my friends.

so thank yall so much for the clarifications and help. i am hoping to get this welded on this monday. and hopefully it will fix my problem...and possibly add some power? i have found it is definetly cheaper to use my friends CATS and have them welded in than it is to buy replacement stock cats. haha

willys5555 · #10 10-28-2009, 06:07 PM

ok so my friend gave me the cats he had and they are the magnaflow cats but they are the replacements for the front cats. he tells me this is how i should run it. He gave them to me and they already have the stock flange on them and the spot for the front o2 sensor. should i just weld pipe after the cat and put a hole in it for the o2 sensor right after the cat? this will keep my CEL from coming on right? (also, where can i find the threaded insert for the o2 sensor at? if i cant buy it like at autozone, i was going to just cut out that section of pipe on my stock pipe and weld it on.)

DarrenWS6 · #11 10-28-2009, 06:12 PM

Quote:

Originally Posted by willys5555

ok so my friend gave me the cats he had and they are the magnaflow cats but they are the replacements for the front cats. he tells me this is how i should run it. He gave them to me and they already have the stock flange on them and the spot for the front o2 sensor. should i just weld pipe after the cat and put a hole in it for the o2 sensor right after the cat? this will keep my CEL from coming on right? (also, where can i find the threaded insert for the o2 sensor at? if i cant buy it like at autozone, i was going to just cut out that section of pipe on my stock pipe and weld it on.)

Correct. You sound well set up now.

willys5555 · #12 10-28-2009, 06:58 PM

great! i just dont want any issues with the CEL. im tired of it running rough right now. lol