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  1. #1
    Jr. Engineer
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    Default clogged cat converter ??

    guys,
    my nephew has a 1994 k-1500 4x4 with 5.7 v-8, and its been about 3 years since we did a total tune up on it. it has 200k miles on it.
    he said he is getting really poor gas mileage now, and when taking off if it really boggish, even when he kicks it into passing gear it take a while for it to pick up and perform half way decent.
    i will check his plugs and rotor and cap in a few days, but i told him to lay under his truck and bang on the muffler and catalytic converter.
    he said the muffler is quiet when hitting it, but when hitting the bottom of the catalytic converter it sounds like there is a lots of loose metal inside.

    would a clogged cat converter cause poor performance ?

    thanks much.

    leonard

  2. #2

    Default

    Yes a clogged cat will cause performance issues

  3. #3
    Jr. Engineer
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    Default

    thanks much...
    we will try and remove it and put a straight pipe in its place.

  4. #4
    Master Mechanic Silverado Junkie's Avatar
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    Lead Hill, Arkansas
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    Default

    Ya, id cut the cat off. It will run better than before. All cats are good for is handicapping your motor. And if you didnt feel like putn a pipe in its place, you could always just hollow the cat out.
    1995 Silverado,Z71, 3-inch lift,2-inch leveling kit, SkyJacker Suspension, short ram-air intake, throttle body spacer, MSD ignition coil, straight pipes

  5. #5
    Jr. Engineer
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    Default

    how would i hollow it out ?
    thanks

  6. #6
    Master Mechanic Silverado Junkie's Avatar
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    Default

    Ive never done it first hand because i allways run straight pipes but ive known folks to cut the cat out, remove the screens on the entrance and exit of the cat, then pound all the guts out of it which hollows it out. Hope that helps.

  7. #7
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    Default

    Quote Originally Posted by Silverado Junkie View Post
    Ive never done it first hand because i allways run straight pipes but ive known folks to cut the cat out, remove the screens on the entrance and exit of the cat, then pound all the guts out of it which hollows it out. Hope that helps.

    cool, i will tell my nephew this trick.
    also, when replacing the cat with a pipe, did you notice any loss in performance or gas mileage ?
    most people are telling me this, but i find it hard to believe.
    thanks

  8. #8
    Master Mechanic
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    Apr 2009
    Location
    Owens Cross Roads, Alabama
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    Default

    my cat stopped up on my dodge so we hollowed it out.we cut the pipe just in front of it and used a crowbar (or somthing similar) and a hammer.just insert the crowbar into the pipe and start hitting the opposite end with the hammer til the junk inside comes apart.we also cranked it up a few times to blow it out to make it a little easier.hope this may help some.i never had a problem with power loss or any differences with mileage afterwards
    -Dylan
    2004 Silverado 4x4
    4.8L
    1986 K5 Blazer
    8" Superlift w/39.5 super swampers
    1992 GMC Jimmy "Blue Bomber"
    4.3L Vortec

  9. #9
    Master Mechanic Silverado Junkie's Avatar
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    Default

    Yes it will run better. We took the cat off my dads ranger and it ran great, better than before. And when we took the cat and mufflers off mine and put straight pipes on it, it ran amazing and sounds awesome. You wont have any regrets takn the cat off.

  10. #10
    Jr. Engineer
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    Default

    thanks guys...
    my nephew had his truck checked out form a friend, and found it to be a super dirty fuel filter. runs like a champ now he says.
    he will hold off on taking the cat out, since he dont have much money.
    but, i now want to take the cat off of my 1990. LOL.

    thanks again guys for the help.

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