Bad Cat?
 

Is there any reliable way to check if a catalytic converter is bad
without removing it?

My XJ has started sounding like it has an exhaust leak when it first
starts up in the morning. There are no obvious visible cracks in the
manifold so I'm wondering if the cat is clogged and is causing excessive
back pressure. It's got 103k on it so it may be bad, but I don't know
how to check it.

-CT

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> Is there any reliable way to check if a catalytic converter is bad
> without removing it?
>
> My XJ has started sounding like it has an exhaust leak when it first
> starts up in the morning. There are no obvious visible cracks in the
> manifold so I'm wondering if the cat is clogged and is causing excessive
> back pressure. It's got 103k on it so it may be bad, but I don't know
> how to check it.

with a vac gauge.

http://www.classictruckshop.com/club...ts/vac/uum.htm

http://www.obd-codes.com/howto/diagnoseengine.php

http://autos.yahoo.com/maintain/repa...ques083_0.html

--
DougW

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> Is there any reliable way to check if a catalytic converter is bad
> without removing it?
>
> My XJ has started sounding like it has an exhaust leak when it first
> starts up in the morning. There are no obvious visible cracks in the
> manifold so I'm wondering if the cat is clogged and is causing excessive
> back pressure. It's got 103k on it so it may be bad, but I don't know
> how to check it.

with a vac gauge.

http://www.classictruckshop.com/club...ts/vac/uum.htm

http://www.obd-codes.com/howto/diagnoseengine.php

http://autos.yahoo.com/maintain/repa...ques083_0.html

--
DougW

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> Is there any reliable way to check if a catalytic converter is bad
> without removing it?
>
> My XJ has started sounding like it has an exhaust leak when it first
> starts up in the morning. There are no obvious visible cracks in the
> manifold so I'm wondering if the cat is clogged and is causing excessive
> back pressure. It's got 103k on it so it may be bad, but I don't know
> how to check it.

with a vac gauge.

http://www.classictruckshop.com/club...ts/vac/uum.htm

http://www.obd-codes.com/howto/diagnoseengine.php

http://autos.yahoo.com/maintain/repa...ques083_0.html

--
DougW

Re: Bad Cat?
 

udaman!
Thanks.

Re: Bad Cat?
 

udaman!
Thanks.

Re: Bad Cat?
 

udaman!
Thanks.

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> udaman!
> Thanks.

np.

I should say that exhaust cracks are damn hard to find.
My header split on the ZJ and it did like your talking,
noise till it heats up and seals again. Eventually if
it's the header, folks will think your driving a diesel.

My header cracked between the two pipes, just in front
of the collector. (the last Y) The only way to find
that crack was to start the engine cold and feel for
exhaust. (you don't have much time to do this before
it gets bloody hot.)

One ol-timer gave me another way. Stick a vacuum cleaner
on the tailpipe then wave a cigarette (smoke source) around
the pipes. your looking for where stuff gets sucked in.

--
DougW

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> udaman!
> Thanks.

np.

I should say that exhaust cracks are damn hard to find.
My header split on the ZJ and it did like your talking,
noise till it heats up and seals again. Eventually if
it's the header, folks will think your driving a diesel.

My header cracked between the two pipes, just in front
of the collector. (the last Y) The only way to find
that crack was to start the engine cold and feel for
exhaust. (you don't have much time to do this before
it gets bloody hot.)

One ol-timer gave me another way. Stick a vacuum cleaner
on the tailpipe then wave a cigarette (smoke source) around
the pipes. your looking for where stuff gets sucked in.

--
DougW

Re: Bad Cat?
 

Clap Trap did pass the time by typing:
> udaman!
> Thanks.

np.

I should say that exhaust cracks are damn hard to find.
My header split on the ZJ and it did like your talking,
noise till it heats up and seals again. Eventually if
it's the header, folks will think your driving a diesel.

My header cracked between the two pipes, just in front
of the collector. (the last Y) The only way to find
that crack was to start the engine cold and feel for
exhaust. (you don't have much time to do this before
it gets bloody hot.)

One ol-timer gave me another way. Stick a vacuum cleaner
on the tailpipe then wave a cigarette (smoke source) around
the pipes. your looking for where stuff gets sucked in.

--
DougW