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Location: Seattle--->ShangHai
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Stupid Question: How do you tell if a cat conv has gone bad?
Short of failing an emissions test after waiting in line for 45 mins and dishing out $15, how do you know it is time for a new cat?
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88 Carrera Coupe Pelican Since 2002 All Zing, No Bling. ok, maybe a little bling. The Roach |
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02-10-2003, 09:32 PM
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I think they plug before they go bad, you may try bumping this in the morning, Kevin
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02-10-2003, 10:50 PM
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Team California
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I believe that the way they are tested is to remove threaded plug and measure pressure being released at that stage, this would indicate a plugged or free-flowing cat. When they go bad they plug up. If your car has been producing normal power, it's probably not your cat that is the problem.
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Denis Trump uses an autopen and votes by mail, in case anyone wonders. 
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02-11-2003, 01:28 AM
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Location: Viera FL
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If engine temp continues to rise when the car is on the road (like on the freeway) is a good indicator that it is starting to clog up.
AFJuvat
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Es geht nicht darum wie schnell man faehrt, sondern wie gut man schnell fahren kann. Ihr Brunnen der nutzlosen Porsche Information |
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02-11-2003, 02:23 AM
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Location: planet earth
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I always thought the test was
Take it off look into it. If you see anything at all (honeycomb stucture ect.) then it was bad. All you have to do to fix it though is take a metal rod to it, cleans it right out.  Of course I say this in jest
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78 Euro 911sc Targa 03 Hayden SCWDP |
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02-11-2003, 04:26 AM
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I think you can just take the car to a muffler shop and they can look at the temperature before the cat then after the cat and tell if it is bad.
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02-11-2003, 04:32 AM
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Before and after temp is the factory method in the repair manuals.
---Wil Ferch
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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02-11-2003, 04:58 AM
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Before and after temperature
Before and after 4/5 gas reading Cat temperature running, should be hotter than exhaust pipe Exhaust pressure only tests for flow, they can fail and not clog. BTDTGTTS
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Stuart Williams '65 911 2.0 '68 FIAT 850 Special '71 GT6 ex-Zundapp collector |
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02-11-2003, 08:38 AM
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You can always tell when it's time for a new cat...it's when the old one is laying on it's back with it's paws straight up in the air and it's as stiff as a 2 by 4!! THEN, it's time for a new cat!!
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02-11-2003, 11:47 AM
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Funny.
Thanks for the responses, i do not think i need a new cat at the moment, just trying to find a good excuse to buy a new exhaust system. Honey, the cat is dead, if i am going to swap it out might as well get SSIs and a free flow muffler while i have the car up
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88 Carrera Coupe Pelican Since 2002 All Zing, No Bling. ok, maybe a little bling. The Roach |
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02-11-2003, 01:34 PM
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Save the $ on the new exhaust and just put in a cat by-pass pipe. You can do it for well under $300 and get about the same HP increase.
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Don 24 Cayman GTS - GT Silver 23 Cayman GTS - Arctic Grey - Sold 97 993 Coupe - Arctic/Black - Sold 13 991 Coupe - Platinum/Black - Sold, 87 911 Coupe - Venetian Blue |
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02-11-2003, 01:49 PM
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1987 Porsche 911 3.2
2013 991 Carrera
