What are some really good ways to check for a clogged cat converter. What are some good signs to tell from driving that the cat is clogged up?

...rotten egg smell coming from the exhaust, poor acceleration. most likely the smell will tell you.







...don't hate!.. respect people that have talent, even if it is in something you don't like or understand.

Sometimes a clogged cat can actually stop the motor from running. It simply provides too much resistance for the motor to overcome and literally stuffs the motor with exhaust. Many times low speed low RPM performance drops significantly and the motor runs rough. However, high speed, high RPM performance can be less affected since the motor is running with enough power to overcome the restriction that the cat is providing. So basically, very poor performance down low, better to regular performance up top can be an indication that a cat has been or is beginning to be clogged.

Brian

so your saying that basically it really would have more of an effect on torque than horsepower. Are there any engine diagnostic tests I can do to check for this? I've heard of the vacuum pressure test guage but wasnt sure how accurate this was.

Well, not exactly. It's all torque. Horsepower is just a measurement of torque over time. It's a low RPM vs. high RPM , exhaust velocity thing. It's basically a restriction in the exhaust.

I'd just take the cat off and see what happens. If you gain significant performance, especially in the lower rpm's, your cat is probably clogged. Or throw a test pipe in there and see what happens. Now, you'll gain some performance just by the fact that you're reducing the restriction if you leave the cat off. If it's a significant gain, then you're looking at a bad cat.

I suppose, if you could measure backpressure before the cat (between the engine and cat) that would be a test, but you'd need a "before" value to compare it to. Sorta make sense?

Brian