bigmouthcivic

I have a 99 Civic Si with 75k miles. The check engine light came on so I used a code reader and it told me "p0420 catalyst system efficiency below threshold bank 1". I was thinking that it was the rear o2 sensor but I am not sure. Just wanted to get some input so I can order the right part.
I am also going to be changeing the timing belt soon and just wanted to know if I should just do the belt or if there is other parts I should changed while I have the belt off. Any info would help. Thanks

b16a3delsol

im not sure about the o2 sensor but when you change the timing belt change the water pump while your at it.

MustangPunk302

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a3delsol &raquo;</TD></TR><TR><TD CLASS="quote">im not sure about the o2 sensor but when you change the timing belt change the water pump while your at it.</TD></TR></TABLE>

I get a new tensioner too if it where mine...

The code P0420-Catalyst Efficiency Low... What kind of equipment you got, can you pull up data parameters on a running engine. If you just want to throw parts on it, yeah throw a o2 on first, not fixed? Then throw a cat on it... Still not fixed, ok better actually find the cause of the problem..

JKov240

Bank 1 should be the first O2 sensor, right? (someone correct me if I'm wrong)

I'd take a shot at replacing the O2 sensor(s) first, that's your best bet because eventually they do wear out.


If you're going to change the timing belt then you might as well be thorough with it while you have everything apart...replace the timing belt, tensioner, water pump, belts, seals, and gaskets. It's better to have it apart once to do everything rather than have to take it all back apart when something fails.

shadowdancer

i would replace all belts, tensioner, and spring. I've never heard of a waterpump failing on a honda. When I pulled my water pump out of my 99 SI, it was clean as can be and spun freely without any problems.

bigmouthcivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MustangPunk302 &raquo;</TD></TR><TR><TD CLASS="quote">

I get a new tensioner too if it where mine...

The code P0420-Catalyst Efficiency Low... What kind of equipment you got, can you pull up data parameters on a running engine. If you just want to throw parts on it, yeah throw a o2 on first, not fixed? Then throw a cat on it... Still not fixed, ok better actually find the cause of the problem.. </TD></TR></TABLE>

Thanks for being a dick it was just a question.

MustangPunk302

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigmouthcivic &raquo;</TD></TR><TR><TD CLASS="quote">

Thanks for being a dick it was just a question.</TD></TR></TABLE>

Not tring to be a dick, I just don't want you to throw on parts you don't need. That's all I meant by it..