Ok here's the deal, i have had these cats, both, replaced twice because 2 weeks to 3 months later they broke up(car sound) The last one was replaced about 6 mos ago. Anyway the car idles pretty bad sitting still(no codes, new wires, plugs, o2, distributer cap, air/fuel little high), and when i put my hand over the exhaust pipes one is hot (left) and one is pretty cool (right) does this mean that somewhere i might have a chunk stuck in there. I have no muffler, and dont hear any rattles, is there any way to check, like lighty tapping the pipes all the way down to listen for solid sounds ??? The exhaust guy wont replace them again, he says it's my car thats the problem ???

 

If your car has a bad miss or burns oil you'll burn up cats pretty fast. The extra fuel or oil makes the catalyst get too hot and come apart.

You can check for exhaust restriction a couple of different ways. Quickest and easiest is if you can get an infrared thermometer. Drive the car down the road till its warm then use the thermometer to check temp the length of the pipes. A plugged spot will be hot in front then cool immediately behind.

A second way is more general. Hook up a vacuum guage to the engine. Rev it to 2000 and hold it while watching the guage. If the vacuum reading starts dropping you have a restriction somewhere.

Then of course you can always take the exhaust loose and look. But thats alot of work.

 

most muffler shops can check it for you for about 10-20 dollars. they drill a hole in the pipe and measure back preasure then weld the hole back up.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

I've also heard in some cases the cat might glow or you will get a rotten egg smell.

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"Rice burners are like tampons...Every pu$$y has to have one"
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

I would try vigorously shaking the pipes to see if anything rattles. If something broke loose it will most likely cause a rattle somewhere.

Dale

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1986 FireBird
2.8L MPFI
1/2 CAI
Gutted Cat, No muffler
Was 700-R4 --> Now T5

Great cars aren't bought, they are built