I'm pulling my hair out. I've been given the run around this week. Took my car to the shop because the Check Engine light was on. First they tell me its the converter and the sensors. I said no way. Called back a half hour later and said I have a leak. Pay the diagnostic charge and go to a dealership. Same thing. Converter is bad. The convertere is just 7 months old. I am in the process of getting the warranty on the converter which was done in 12/04 to replace this. Both shops show the same code.
This accord still runs good , looks good and gets 31 mpg with 170, 000 miles. Could it be something beside the converter? Something secondary.? I drive this car back and forth to work daily (80 miles round trip). Doesn't burn oil, regular maint.

 

With those high of miles that is why your cat went bad...if both places are telling you its the cat based off the codes then replace the cat.

But IMO do it yourself and save yourself some money.

 

If everything else is equal, the catalytic converter rarely fails on its own ( with the exception of the element breaking loose). Considering that the converter is downstream from everything involved with the emissions or fuel systems, it has no way of setting a code. Sensors set codes, wiring failures set codes, bad fuel and leaking gas caps set codes but converters can not.
There is an underlying condition which is causing the converter to "fail", thats why your looking at another converter after only 7 months. Throwing another converter at the problem will be a total waist without addressing the CAUSE of the failure rather than the result only.
I'd look at the original report with a slightly cooler head and evaluate what they really said.

P

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">Considering that the converter is downstream from everything involved with the emissions or fuel systems,</TD></TR></TABLE>

Yea but on obd2 cars the air/fuel mixture is regulated by what both o2 sensors read and their difference. The cat plays an essential role in emissions and with 2 o2 sensors tied into actual a/f ratio it will also affect overall performance and economy.

 

True, but the converter doesn't do anything else than process what it's given. Either an excessively rich or lean fuel mixture can damage a converter. The second o2 sensor does nothing more than verify how successful the converters' doing it's job.
This is a classic synario, this car is now going on it's third converter. Considering how many Honda's live to ripe old ages and never need a converter speaks loads about it's design. To have three bad converters in 170,000 miles really stretches statistical probability. Odds are that nothing else was checked during the last go around.

P

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote"> Either an excessively rich or lean fuel mixture can damage a converter. </TD></TR></TABLE>
True, but that should be picked up on by the ECU and a trouble code should be stored.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">To have three bad converters in 170,000 miles really stretches statistical probability. </TD></TR></TABLE>
If i'm reading right, hes currently on his second converter. We replace tham all the time on 6th gen accords under warranty. (80,000 miles) He didn't say if his new converter was from Honda or not. If it was an aftermarket unit, i wouldn't be surprised about the short life.

 

As I understand it, the first (OEM) converter was replaced 7 months ago. From that time till now it has been running on the second converter; but now it requires a third. To be ABSOLUTELY accurate, I should have said the car is now going on it's third converter in 170,000 miles.
I stand by my original prognosis, there are other factors here causing the converter to fail.

P

 

I have had the same issue with a 1999 Accord 4cyl LX. There is plenty of history on this issue on many Honda forums. My first CEL came on around 80,000 miles after using cheap ARCO gas for the first time. The CEL code was P0420 (going from memory here), which measures the difference between the front and rear O2 sensors. When the voltage difference between the two hits a certain range the CEL is tripped after a few drive cycles. The actual voltages can be measured with a multi meter at the O2 sensors or by special software using the OBDII port.

After researching this issue, the approach I took is to do nothing. My car ran fine, no lost in power and the MPG stayed the same. I cleared the code with a code reader or by pulling fuse 13 in the passenger side fuse panel a couple of times and it went away for a few months. The same code comes back every 6 months or so and I actually just leave it now. After about a week of driving the CEL clears it's self and yes I have checked the CEL light and it has not burned out.

From what I have read and experienced I feel that there is some sort of design flaw that has the system set really sensitive. New O2 sensors may solve the problem...., but it's pricey to get two OEM sensors. I have driven the last 20,000 miles without a single problem and have passed WA emissions recently. I would suggest not doing a thing because modern day CAT's don't go bad all that often. The dealer can only do what the computer tells them while taking your money.

My 2 cents, Chris

 

here is a great cheap way to fix your cat so it doesn't blow a cel anymore. notoriousB did this for my accord and I've been running with out a engine code for about a month or so. I also just passed emmissions with out a problem.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by notoriousB &raquo;</TD></TR><TR><TD CLASS="quote">yup, we did this for a grand total of $3.99+tax i believe!

get this "help" part at your local parts store: 18mm defouler - comes in a pack of 2

here's the package and the two defoulers screwed together


i drilled out the bottom of one with a 1/2 inch drill bit - go slow, use lots of oil, it's thick

i don't have any pictures of the one drilled out alone, but here's two pics of the final product, one from the bottom one from the top. in the second pic you can see how it was drilled. the drilliing is done to be able to fit the o2 sensor thru the 1st defouler.





final product all installed, and skabone confirms "it works!!" :D



had to persuade the heatshield slightly to clear the new longer o2 sensor but that's no problem.</TD></TR></TABLE>

 

im trying to do that mod this week but i havent had time, but when i took the O2 sensor out. I Noticed part of yellow brown stuff was in the O2 holes on the sesnor itself. So i got a flash light and looked inside, and what i saw was a broken honeycone and about 60% hollow.

by the way Shamus1,

how is your driving style that can play a big part of it aswell.