Cat converter question

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sdigs

NAXJA Forum User

Location

Albuquerque, New Mexico

• Sep 16, 2008

• #1

I'm trying to chase down an over heating issue and someone said the cat might be plugged up. How owuld I know? I had an emissions check a few months back and passed just fine. would that indicate that it is OK?

 

Hypoid

NAXJA Member

NAXJA Member

Location

Golden, CO

• Sep 16, 2008

• #2

That would indicate that it was OK a couple months ago. Dump too much fuel and it could be clogged by now. What year XJ?

You could remove the cat and try looking through the core.

You could use a vacuum gauge to check for a plugged exhaust.

I've read here that an IR thermometer will indicate wether or not a CAT is functioning.

 

S

sdigs

NAXJA Forum User

Location

Albuquerque, New Mexico

• Sep 16, 2008

• #3

Its a 94, 4.0l automatic. I had the problem before the emissions test also so i think it is good. How would you check with an IR thermometer? i'm guessing i would shoot temps at the inlet and outlet of the Cat and a large difference would indicate obstructed flow.

 

Hypoid

NAXJA Member

NAXJA Member

Location

Golden, CO

• Sep 18, 2008

• #4

If it is working, the output temp should be higher than the input temp.

 

xcm

NAXJA Forum User

Location

Southern Oregon

• Sep 18, 2008

• #5

Hypoid said:

If it is working, the output temp should be higher than the input temp.

Click to expand...

ok... thats not very descriptive... how would it indicate its NOT working properly, id imagine it would still be "hotter on the outlet side....."

 

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poorboy_616

NAXJA Forum User

Location

Vancouver, WA

• Sep 18, 2008

• #6

Nope, the cat when working correctly will always be hotter on the out, than in. If it's plugged you have heat before, but not after. If it outright quit without clogging, the heat would be the same.....