bad muffler

[kreb]

i wanted to see if there was a way i can test to see if the muffler is still good

benjamin

[Treeshark]

Rev up the Jeep, and if it's still quiet enough for you, it's still good! :D

Just kidding, what do you mean, back pressure?

[kreb]

to see if it is clogged. i want to see if the bad cat ruined the muffler.

benjamin

[carrotman]

Hook up a vacuum gauge. Note idle vacuum number. Rev engine to 2,000. Vacuum should be steady and higher at 2,000 RPM than at idle. If the vacuum falls below idle reading or the needle oscillates there is a restriction in the exhaust system. Could be a frozen heat riser valve, choked up muffler, loose baffles in the muffler, crushed tailpipe, or clogged cat.

[La Wagoneer]

Use the test I used on my old Volvo (I know it's a bad word) shake it, if it rattles it's full of crud from the cat.