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Catalytic converter not bad but getting hot - lean fuel issue?

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Old 09-26-2017, 06:53 PM
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Doesn't the '94 converter have shields on it?
Old 09-26-2017, 07:02 PM
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Based on the latest information, I'd just get some shiny thermal insulation material and line the underside of floor above the exhaust with it to reflect the heat back down. Design Engineering has a whole line of products for that purpose. You might be able to find something cheaper.

http://www.designengineering.com/cat...-sound-barrier
Old 09-26-2017, 08:04 PM
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I'm guessing a heat shield fell off. I'm with shaky here, get something to deflect the heat.
Old 09-27-2017, 08:15 AM
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The cat has a built in shield on top and bottom. But nothing else above the cat.

I think you guys are right in your suggestion to get some thermal shielding for the underside of the car, above the cat.

I'll update and let you guys know if that works. Thanks!
Old 09-27-2017, 03:53 PM
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Originally Posted by centuryhouse
When I pulled the plugs 2 weeks ago (after the problem existed) they looked white-ish.

White-ish would indicate a lean condition. The insulator should be a light brown/reddish color.
Old 09-27-2017, 06:41 PM
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I measured the temp of the floor under the carpet in the back passenger side. 185 degrees at the hottest spot (over the Flowmaster muffler).

Is that normal? Is it dangerous, as far as being hot enough to burn carpet?

Last edited by centuryhouse; 09-28-2017 at 06:43 AM.
Old 09-28-2017, 06:44 AM
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I should add - the 180 degree floor pan temp is AFTER I put some heat shielding over the top of the cat, the pipe between the cat and muffler, and over the front half of the muffler.
Old 09-28-2017, 07:50 AM
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IMHO somethings not right there. I recently gutted my interior and not even the paint on the floor in that area was discolored. Also I've never had anyone who have sat there complain. How close to the body is the cat sitting?
Old 09-28-2017, 08:43 AM
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Originally Posted by EZEARL
IMHO somethings not right there. I recently gutted my interior and not even the paint on the floor in that area was discolored. Also I've never had anyone who have sat there complain. How close to the body is the cat sitting?
Interestingly, the hottest part of the floor (180 degrees) is over the muffler now. Due to the contouring of the floor there, just in front of the back seat, the floor is probably 6" away from the top of the Flowmaster muffler.

I think some external shielding over the back of the muffler will help.

But then again, is 180 degrees dangerous to the carpet? It sure feels hot, but it doesn't sound that bad considering the interior of a car in the summer gets almost that hot. Maybe I should just add some heat resistant insulation under the carpet and quit worrying about it?
Old 09-28-2017, 10:52 AM
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I think I found the culprit. I didn't really look this far back before because the hotspots were a little further to the front.

I think the previous owner cut a layer off the bottom for some reason, leaving only the steel pan exposed just behind / above the back of the muffler.

That space just just under the back passenger seat, and the heat is radiating forward from it into the back floorboard.

I don't know what that missing layer is made of, but a heat shield should help.






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