Catalytic Calamity

[warmstrong]

Ive been getting a service engine soon light at idle over the past few weeks and its been suggested to me that its probable a clogged cat. It goes off as soon as you start moving. The remedy that was suggested is to take the cat off and pound out the inards with a pipe and the put it back on. Does this sound right?

[redrider2001]

Ahhh, the old Gutting the Cat procedure. Not good if you need to pass smog.

[asilverblazer]

No, it does not sound right. Have you checked the code causing the "Check Engine" light? That will insure that the Catalytic Convertor is bad. If it is toast, gutting it will not solve the problem. The O2 sensors monitor the Catalytic Convertor performance by taking readings of the exhaust before and after the convertor. With little to no difference between the readings it assumes the convertor is not functioning. With no guts it will not function, thus there will be no reading difference, meaning the "Check Engine Light will stay on.

[warmstrong]

Ahhh, the old Gutting the Cat procedure.  Not good if you need to pass smog.

 

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The main reason I would be doing it is to improve my gas mileage and power. From what Ive been told, the cat being clogged will adversely effect both. If the light stays on, but performance and mileage improves, I can probably live with that as long as its not hurting anything. I dont have smog to worry about where im at either.

[asilverblazer]

Gas mileage and performance gains (probably none) will not be worth rotting everyones lungs out, as well as the massive fine if caught.

[dewfpo]

First, a bad cat almost never means a clogged cat. If you had a clogged cat you would have different problems.

 

Second, I would always check the output of the rear O2 sensor (the one after the cat) before ever condemning the cat.

 

DEWFPO

[warmstrong]

First, a bad cat almost never means a clogged cat.  If you had a clogged cat you would have different problems.

 

Second, I would always check the output of the rear O2 sensor (the one after the cat) before ever condemning the cat.

 

DEWFPO

 

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I got lucky and found out that we had a vetronix tech 1a at work, so I took it home to read the trouble code. Came up with 35 which is a bad IAC valve. Judging by what the Haynes manual says that should be pretty easy to clean and I wont have to mess with the cat. A lot of guys at work are still telling me that they think my cat is partially obstructed and thats what caused the IAC valve to get fouled, due to exhaust backing up. Other symptoms Im having is reduced power and poor performance when towing my bass boat. My gas mileage is averaging 8-10 when not towing. All this and the motor is virtually new. Crate long block with about 30,000 on it and new everything. Shouldnt be having this problem, and the IAC valve error was the only code in the history. Could this be causing the poor performance, or is there something else like a plugged cat that could be adding to it?

[dewfpo]

The IAC is going to be easier and cheaper to clean and or replace (if needed) than the cat so I would definitly clean it first, reset the code(s) if you can and drive it for a while and see if it solves your situation.

 

I always say, look for the cheapest and easiest solution FIRST...... then move on down the list one item at a time.

 

DEWFPO