So i a few weeks ago i threw a P0420. I had notice before that my motor/exhaust sounded a little louder. i worried that it was gonna be the cat. but after some inspection i find this







now i dont pretend to be a mechanical genius, but im pretty sure i shouldn't be able to put a butter knife into my cylinder head. any suggestions other than the obvious. get honda parts, or something generic? will this cause a 0420? 1999 accord ex 4 cylinder.

thanks in advance.
justin

 

thats nothing to worry about. Those are just voids in the casting of the head. Thats not actually the exhaust ports.

I'll see if I can find a picture to show you what I mean.

 

i believe it's these voids... pic taken during my build...

 

yeah that would make sense. the gaps are offset from the manifold cylinders.

 

back to square 1

 

these are a couple pictures I used from a while ago when someone asked the same thing. But rhdune16's picture shows it better

 

that is the code for either cat or 02 sensor...for a 1999 it sounds like cat failure is unlikely...unless you have a lot of miles or put something you shouldnt put into your tank...

 

115,000 miles

 

and i do notice a lot of exhaust noise. seems to be coming from the engine bay. i have heard that cracks in the manifold can trip this code. i guess i am curious as to which o2 sensor is triggering this code. there is one in the cat. correct?

 

not to beat a dead horse here, but wouldn't an o2 sensor malufunction trigger an o2 sensor malfunction code? not one about cat efficiency?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cronousman &raquo;</TD></TR><TR><TD CLASS="quote">that is the code for either cat or 02 sensor...for a 1999 it sounds like cat failure is unlikely...unless you have a lot of miles or put something you shouldnt put into your tank...</TD></TR></TABLE>

The catalytic converters on 98-02 Accords are notorious for failing.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jravensc &raquo;</TD></TR><TR><TD CLASS="quote">not to beat a dead horse here, but wouldn't an o2 sensor malufunction trigger an o2 sensor malfunction code? not one about cat efficiency? </TD></TR></TABLE>

Typically, yes, but unfortunately that's not always the case.

Try to track down the exhaust leak. While a friend steps on the gas a bit, you can try to feel for the escaping air. (Obviously, be careful not to touch the exhaust while it's hot.) The flex joint is a common leak point.

I found my friend's exhaust leak by accident, when I Seafoam'd his car. I was giving it some gas as smoke was pouring from his exhaust pipe, when I noticed a little bit of smoke coming from underneath the car. Coincidentally, it was the flex joint that was leaking.

 

Have you checked the downpipe portion of the manifold?