sky2002

I have a 1999 Acura TL with 188K Miles.
I recently fixed my misfire problem by replacing one of the six Coilpacks.

Now, I am experiencing OBD II code 0420.
I am planning to change my O2 Sensors, but if that does not fix it. I am planning to also change my Catalytic converter.

I am not a very good mechanic and I have never done either of them before.
From my search, I see the replacing O2 Sensor is not that bad.

However, I am not so sure about replacing Catalytic converter.

I would appreciate any helps or tips on how to replace Catalytic Converter.
Also, can I get recommendation as to what Catalytic Converter to get. Any website links would be helpful.
How do you get the Catalytic Converter out? Any special tools or chemicals needed?
Do I need to weld the new catalytic converter or is it a direct fit with bolt, etc?

I would appreciate any info, diagrams, comments

Thanks in advance

acutee

some shops have the tool to test your o2 sensor. otherwise replace o2 sensor first. it is cheaper and easy to do. You have to make a good guess to make your decision, like gas consumption. if gas consumption is high more likely you have bad o2 sensor rather than c.converter. I think bad converter pullutes the air rather than consuming your gas; but I could be wrong.

01tl4tl

since we have an O2 sensor on both sides of the cat-(most years) it will make things bad if either or both parts have failed

There is an electrical test with a basic multimeter to see if O2 is in parameters

Muffler shops can test the cat for flow/pressure and temp to see if its working right

O2 is a common wearout item- denso is the stock brand and good replacement choice.
After the bad coil- did you replace the plugs or the one plug where the bad coil had been?- that will screw with the computer if its loaded up with fuel residue in that cylinder~

Should reset the computer just for good measure- let it relearn and retest the system- then check codes again
Pull the CLOCK fuse #13 on passenger side inside car- after 1-2 minutes put it back in and start car
Seafoam the intake manifold and gas tank to clean everything so you have a baseline

Codes are NOT diagnosis- they are clues

sky2002

I replaced all 6 Spark Plugs before knowing that the coil was bad.
Afterward, everything was fine. A day later, I see the check engine light went on again and that's when I get the cod 0420.

Ok, I will try to reset the system.

01tl4tl

confirm which brand spark plugs used?
Seafoam it, and recheck the codes after ECU reset by clock fuse

sky2002

NGK Iridium IX

TLer trash

If the light comes back on, have it read to see if it's the same code. If so,try a can of bg44k in 1/4 tank of fuel and do the sea foam burn off drive. I've had this keep the light off for several months to over a year. If it persists, try the front o2 sensor, but not the rear just yet. If it still codes 0420, you could try the rear o2 sensor now, but it's not worked for me yet. It has for others on this forum. On a car with your mileage, o2 sensors can pay for themselves in less than a year in fuel savings.

01tl4tl

would you believe other car makers say replace the O2 sensors at 60k miles!

I have not checked my owner book to see if acura has a suggested time frame or if its like the valves- as needed
There is an electrical resistance test on the O2 to see if they are working right
without removal
If you have been fooling the system with resets for several months- fix the real problem

TLer trash

Early design o2 sensors without heaters typically were scheduled for replacement at 50-60k. I haven't seen a recommended replacement mileage from any car manufacturer on the newer heated type, but I think some of the sensor mfgrs have recommendations of their own. You can check an o2's heater with an ohmmeter, but a voltmeter will only do some basic testing of a sensors real performance. I personally think a scan tool and a lab scope or equivalent are required for any real testing. It doesn't help that car mfgrs' specs are so loose that almost any sensor that doesn't set a code will pass. The acid test is typically mileage improvement after replacement, but with many cars now having 4 sensors at $250 a pop I'm not as confident as I used to be about recommending this