Is my Cat gone????
Thread Starter
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
Is my Cat gone????
How can you tell if a catalytic converter has given up the ghost?
Decided to have my car dynoed today. Drove about 25 miles to have it done. Two pulls and my AFRs measured at the driver side header before the catalytic converter.
Was satisfied with the results.
Got back in the car and headed home. No problem whatsoever. Got off the ramp and went up hill and the car sounded like crap. Seemed to be coming from the left side. A rattling, pinging, marbles in a can type noise. Sounded as though something was loose in the exhaust system, and was particularly pronounced under load and uphill.
Got the car home and put it on ramps and jackstands thinking that a flange bolt may have gotten loose. Tightened every bolt in the system from the heads back to the catbacks. Hardly any were loose to begin with.
Road tested it and still the same "occasional" marbles in a can type noise.
I have no current codes and the car runs fine.
I am wondering if something let loose in the driver side catalytic converter. Anyone else have this happen?
Oh, BTW
327.9 RWHP /341.3 RWTQ. AFRs in the 12.9- 13.1 range. I will post the sheets.
Decided to have my car dynoed today. Drove about 25 miles to have it done. Two pulls and my AFRs measured at the driver side header before the catalytic converter.
Was satisfied with the results.
Got back in the car and headed home. No problem whatsoever. Got off the ramp and went up hill and the car sounded like crap. Seemed to be coming from the left side. A rattling, pinging, marbles in a can type noise. Sounded as though something was loose in the exhaust system, and was particularly pronounced under load and uphill.
Got the car home and put it on ramps and jackstands thinking that a flange bolt may have gotten loose. Tightened every bolt in the system from the heads back to the catbacks. Hardly any were loose to begin with.
Road tested it and still the same "occasional" marbles in a can type noise.
I have no current codes and the car runs fine.
I am wondering if something let loose in the driver side catalytic converter. Anyone else have this happen?
Oh, BTW
327.9 RWHP /341.3 RWTQ. AFRs in the 12.9- 13.1 range. I will post the sheets.
Pro
Joined: Sep 2002
Posts: 525
Likes: 0
From: Kentucky
I have had a few cats go on me in the past with my camaro and a few other jeeps. My experiance with it is that when they make a rattle noise and such when you are at a basic cruise or idle speed. When I would go into WOT it would quite because the pressure going through would pin it so it could not rattle. Chances are one of the cores has come loose. But check and make sure someone did not leave a strap or somethign under it too lol. I am sure you look under it but you never know 
Chances are its your cats. One way to also check is get it up in the air and hit the bottom of it and see if it rattles, could be a loose O2 sensor as well. Get under there and take a look
Damon
Chances are its your cats. One way to also check is get it up in the air and hit the bottom of it and see if it rattles, could be a loose O2 sensor as well. Get under there and take a look Damon
Thread Starter
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
I went under it twice today. The 02 sensors are tight, and clearances appear to be good. Nothing seems to be contacting the exhaust system anywhere. But it sure sounds like it. Like a golfball sized stone is on the inside of either the header, the cat, or the exhaust pipe. And sometimes like a marble sized stone is in there. Sometimes its loud, sometimes barely audible, but definitely there.
I thought about removing the x pipe and cats and taking a look.
I'll contact the people at KOOKS tomorrow.
I thought about removing the x pipe and cats and taking a look.
I'll contact the people at KOOKS tomorrow.
Thread Starter
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
Originally Posted by shurite44
Hey maybe one of the screws in the vararam made it all the way back to the exhaust system. 
I thought it might be pinging, thats almost what it sounds like, but with a tinny type quality because the system is so thin. I hooked up my Predator and saw nothing unusual
Burning Brakes
Joined: Apr 2003
Posts: 908
Likes: 4
From: TROY MI
Originally Posted by EB20003
I went under it twice today. The 02 sensors are tight, and clearances appear to be good. Nothing seems to be contacting the exhaust system anywhere. But it sure sounds like it. Like a golfball sized stone is on the inside of either the header, the cat, or the exhaust pipe. And sometimes like a marble sized stone is in there. Sometimes its loud, sometimes barely audible, but definitely there.
I thought about removing the x pipe and cats and taking a look.
I'll contact the people at KOOKS tomorrow.
I thought about removing the x pipe and cats and taking a look.
I'll contact the people at KOOKS tomorrow.
Thread Starter
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
Originally Posted by yankeevetteconvert
Check the rear clamp on the X-pipe. On my install the passenger side clamp was touching the frame rail and was causing all sorts of noise inside the car. We rotated the clamp 90* and the car is dead quiet.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If the catilist bed is damaged and loose, you can test it by using a pubber mallet and lightly rapping the exhaust system componets. If the bed is loose, you will hear it. You can also use a infred temp probe to measure the temp of each CAT. If one is way low,,, it's BAD.
BC
BC
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