Testing exhaust backpressure?
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Testing exhaust backpressure?
I'm suspecting I have melted cats, but how do you test for that?
I have stock exhaust, if I drop the mid-pipe for a test drive I lose the O2 sensors. Any other way to test?
I have stock exhaust, if I drop the mid-pipe for a test drive I lose the O2 sensors. Any other way to test?
Resident moron
Joined: Jun 2003
Posts: 4,746
Likes: 20
From: Assachusetts
I don't know of any way to test, but dropping the mid pipe won't hurt. Unplug the rear O2s, it will set a code but it won't hurt anything. I had no rear O2s on my old car for a few weeks before I programmed them out. Car was just a little bit sluggish from the code.
Dope
Dope
Pro
Joined: Nov 2003
Posts: 532
Likes: 0
From: herminston oregon
melted cats
undefinedyou can drill a small hole in the pipe in front of each cat. test them with the engine running. or a vacuum gage to the engine while running. if theres any exhaust back pressure, the gage will go down slowly. if the cats melt, it's a good chance the mufflers melted also. you can take the mufflers loose and see if it runs any different. the computer should tell you if theres a problem with cats
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Originally Posted by myblackC5
undefinedyou can drill a small hole in the pipe in front of each cat. test them with the engine running. or a vacuum gage to the engine while running. if theres any exhaust back pressure, the gage will go down slowly. if the cats melt, it's a good chance the mufflers melted also. you can take the mufflers loose and see if it runs any different. the computer should tell you if theres a problem with cats
Melting Slicks
Joined: Oct 2003
Posts: 2,834
Likes: 91
From: California
Your blower and the string of 100 degree days we've had have done you in. I'll be down in a bit to trade you my stock exhaust for your blower, if you like you can start the removal and I'll be there in 30 minutes..
Thread Starter
Melting Slicks
Joined: Jun 2002
Posts: 3,060
Likes: 3
From: Dublin CA
Originally Posted by Threed
Plugged cats can normally be seen with a vaccum gauge. At higher sustained RPM your vaccum will drop off due to the lack of flow in the exhaust system. 
Tony, very funny!!
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