Anybody care to list symptoms of a bad cat convertor?
Thanks!
Thanks!
Symptoms of a clogged/bad cat convertor??
- Thread starter Ramblin Fever
- Start date
- Status
Lack of acceleration, boggy feel on accel.
Manifold vac higher than normal (absolute pressure), trending to "0" when throttle is opened gradually with no load. On carbed vehicles visible gas blows back out of carb when engine is revved.
Manifold vac higher than normal (absolute pressure), trending to "0" when throttle is opened gradually with no load. On carbed vehicles visible gas blows back out of carb when engine is revved.
On a 96 or newer car the computer will throw a cat converter code.
Shouldn't that be less vacuum than normal (higher absolute pressure) ? I agree with the rest. Rickey.
Perhaps not--sometimes the excessive backpressure will cause an "EGR flow excessive" code. Especially if the cat is physically damaged and clogged as a result.
Another way to organise a partial/ some do - some will later list ;
From the Drivers seat
Fuel economy .
Power/power delivery - throttle amount/response - esp. on accel and deccel .( As per prev. post. ) ie sluggish, bogey , flat , unresponsive , etc .
Sometimes/usually , faster warm up and slower (RARE ) starting as well .Maybe more knock or near knock running .
CEL/#2 O2 sensor /emissions test issues .
From under the Hood ( BASIC ) ;
Oil consumption increase - ( leak/burn ) - quick to get dirty - sometimes more gasoline smell - more often - longer period of time of present .
Depending on specifics , T/B , PLENIUM , EGR , PCV , OTHER dirtier faster . Plugs show signs of running hotter/other
Signs of heat damage/stress both underhood but esp around CC .
Theres more depending , but if you see enough out of above , save yourself some time and go get the Vac . gauge .
Or go in reverse - gauge first - then visual second .
From the Drivers seat
Fuel economy .
Power/power delivery - throttle amount/response - esp. on accel and deccel .( As per prev. post. ) ie sluggish, bogey , flat , unresponsive , etc .
Sometimes/usually , faster warm up and slower (RARE ) starting as well .Maybe more knock or near knock running .
CEL/#2 O2 sensor /emissions test issues .
From under the Hood ( BASIC ) ;
Oil consumption increase - ( leak/burn ) - quick to get dirty - sometimes more gasoline smell - more often - longer period of time of present .
Depending on specifics , T/B , PLENIUM , EGR , PCV , OTHER dirtier faster . Plugs show signs of running hotter/other
Signs of heat damage/stress both underhood but esp around CC .
Theres more depending , but if you see enough out of above , save yourself some time and go get the Vac . gauge .
Or go in reverse - gauge first - then visual second .
Last edited:
In many places in Texas you have to have exhaust emissions measured and many will give readouts to the pollution level. As the catalyst gets poisoned from oil, gas, and air combustion metals, the catalyst will not be able to break down and reduce exhaust emissions enough to pass. I've even heard that roadside emissions testing on vehicles passing by will even get you a ticket in the mail if your exhaust emissions are excessive.
I've heard that you will get better exhaust emission test results if you change your oil right before it is tested and it would probably be a good idea to use an oil with a low Noak Volatility number.
I've heard that you will get better exhaust emission test results if you change your oil right before it is tested and it would probably be a good idea to use an oil with a low Noak Volatility number.
I just want to quote this for absolute truth. A vac gauge is probably on of the most useful yet underutilized tools out there. You can use it to detect incorrect ignition timing, misaligned cams, bad cam lobes, valve problems etc as well as backpressure problems.
- Status
