That was for slomofo. HONDAPARTSMANMIKE knows his stuff!

 

I can tell you one thing thats not true about my car...the engine isn't worn out at 105K. Original engine and miles. I do believe the cat is the original too, so it probably has gone to the *******. If there isn't a exhaust leak before the cat, and the CEL still comes back on after a while with the same code, then Im sure my catalytic converter needs replaced.

 

Cool! replace the cat with a Honda part and it will last another 105,000 miles

 

Wow, so Honda Master Techs no longer check cars? They just change whatever part the scanner shows? That's nice to know.

Scenario: 97 Civic with auto trans and cat on the exhaust manifold comes in with a huge crack in the manifold and has a code P0420 (Accord/Civic with broken manifolds are extremely common). There's no O2 sensor code, only a P0420. What are you going to do?

I never said the cat was not the problem, it could very well be the problem, but you can't rule out all other possibilities.

 

Damn! Its like im trying to teach a monkey how to read. A leak in front of the cat will not create the same waveform on the rear O2 sensor! Its just not possible. The ECU expects a flatter waveform at the secondary O2. If the front O2 LT fuel trim is more than 100, like an exhaust leak, It wont kick a P0420. Period! I dont care what you have read!

 

I'm a tech.

There's a huge Honda and a Huge Acura logo painted on our building.

We also do exhaust work.

I'll leave it at that.

PS - Your e-***** is much larger than mine.

 

Thanks. My toolbox is oversize too!

 

I finally had an excuse to drive my 'Lude on the freeway last night to test the CEL after reseting it. I drove 55 miles without the CEL coming on. I was sure that it would too, so maybe the CEL engine code P0420 was a faulty happening?

 

Slomofo,
I think you're the only one in this thread providing objective advice. Thank you.

Do you know why a leak before the cat causes catalyst inefficiency? I'm looking at a leak between the o2 and cat possibly causing a P0420.

 

From my experience, this is a clogged EGR system. This is rampant in the H22A. There was a TSB about it.

A bad/clogged cat is something you can usually feel (from lack of power) hear (poor exhaust note) and smell (rotten eggs).

The H22A at this mileage is known for a clogged EGR system. It requires you to pull the plugs by the intake manifold, clean out the system, and press in new plugs.