Hey all, so I got a CEL Sunday, got it scanned today. Came out to be code P0420. The description mentions "bank 1". I did a search and got so many varying answers, some say its the cat that is bad, others say its the primary O2 (which is my thinking).

I've got just about 230K on the car. I replaced the originial cat some 2 years ago with a Random Technology high flow cat. Then I had to replace it again due to exhaust leaks from it. So the cat on there now is about 1 yr or so old. I guess it is possible the cat is bad again, but I'm leaning more towards the primary O2 being bad. Both O2 sensors are the originals. When I had to replace the original cat, I think it may have been a diff. code? Because, I dont remember it mentioning the "bank 1" part in the description.

How can I be sure which is bad? I may just have to buy a bi-directional scanner and look at sensor voltages. But I'm on a budget and can't really afford one, lol. Hopefully my HT Type R homeys can help me out! Thanks in advance!

 

http://www.obd-codes.com/p0420

 

Thanks for the link! After reading that, I'm guessing its more the CC than anything else. But I don't want to spend 400-500 on a new OEM unit, lol. I just may have to get professional help to diagnose and narrow it down to the actual part that is bad. I'm praying its not the CC, lol.

Thanks again for the help!

UPDATE: a new OEM cat from DelRay Acura, is $674, yikes!

 

Code 420?

Hmmmmmmm...

It's smoking too much... oil

I all seriousness, you want to find the root cause of the failure. At 230k+ without a rebuild, I'm willing to bet your valve guides are toast and your oil control rings are shot.

If you just throw another catalyst in there it might just be a band-aid. Not a permanent fix.

 

Thats a good point actually. It does burn a butt load of oil. I don't pay attention to how much per what mileage. But I tried stretching my oil changes to 7500 miles, and it typically gets pretty low before I reach 7500. I didn't even know/realize that could be a factor. I don't have money for a rebuild.....it may just be time to get rid of her....I'm sad now. I've had since brand new back in '98, I'm married now with 2 kids....its about time to stop being selfish and sell her lol.

 

run a spacer on your secondary o2 sensor, they're called CEL deleters on ebay

 

Yeah.

The oil is plugging your catalyst. If you buy an OEM one, it will plug-up a lot faster than an aftermarket one.

Such a shame you'd have to sell it. Where are you from?


This might also be another temporary fix.

 

I'll take a look, Thanks yeedub. Is that also called/something to do with "sparkplug foulers" or defoulers? Sorry I can't remember the jargon, lol.

UPDATE: yeedub, i couldn't find any CEL deleters on ebay, search came up empty. I did find O2 sensor extenders, not sure if those are the same thing as CEL deleters.

I'm in Northern VA. Yeah, I don't want to sell it man. I've had it for 15 years, its a big part of my life. I don't even know what I could get for it, might not be worth selling it. I'll have to think it through very carefully. Thanks again for your help!

 

A friend of mine tossed the idea of possibly a bad PCV valve? What do you guys think? If that were true, wouldn't it throw a diff. code? How could I tell if its bad?

 

Your cat is bad. Install a spark plug anti fouler in the secondary o2 to pull the sensor out of the stream so it reads right. Aftermarket cats will cause P0420 after a short period of time.

 

Thanks Evs!

 

http://forums.evolutionm.net/evo-how...cel-light.html

 

Yup grab a defouler off ebay, I like the angled ones because it preserves the ground clearance . If you dont mind possibly scraping, you can go to any auto parts store and look for the Dorman HELP! sparkplug defoulers which are only a few bucks

 

Thank you for the link HondaPartsHero!

Thanks again yeedub! Is there a certain thread size I need or all they all a universal size? I'll look into it more when I get home from work.

 

I'd replace the secondary o2 sensor and see what happens.

 

cats work off of heat. when its coated in oil film it wont get to operating temp and the chemical change cant occur. you get that fault 420 when the front and rear o2 sensor see the same amount o2 in the exhaust. the front will cycle lean rich or hi voltage and low the rear will hover just lean of 14.7 to 1 normally. right now i have a test pipe with an o2 spacer and stock ecu on my 01 r with no check engine light. i would do that for now till you have the money for rebuild. if you keep throwing cats and sensors or whatever you feel is wrong they will foul out after a short time.

 

I'm tempted to do that, but If I was going to do that I'm going to buy OEM parts which is about 260-275 for either the primary or secondary O2. But I'm on a budget and these parts are too expensive to just throw at the problem. I'm reminded of Eric the car guy on youtube, he says to troubleshoot and not just throw parts at it, lol.

I'm tempted to buy one of the Actron scanners that lets you see real time data, so I can monitor the primary and secondary O2 sensors' voltages. I saw this on youtube, from guess who, Eric the car guy, lol. But that scanner is about $200.

So frustrating I tell ya, and I can't find my "easy" button. lol

 

you are making the problem bigger than it is honestly. just get a $50 test pipe and a 90 deg rear o2 spacer. its the cheapest thing you can do for one and 2 if you do have oil over everything and you put a new part on you are wasting your money. those joe shmo scanners arent fast enough to give you a good voltage to look at. the sample data at a set rate and you may not even see the problem as its happening. i have had magnaflow cats fail after only 2 years for no other reason than age so if you have some car sound cat that might be your only issue. most issues ive seen when it comes to oil burning cause low voltage or slow response faults for o2 sensors not cat efficiency faults. sooo if you did have a issue with sensors there would be more than just a cat fault.

 

My car will have to undergo emissions testing eventually, and since I don't know how emissions testing done here in Northern VA, i.e. visual inspections or tailpipe sniffing, I don't know if a test pipe is viable for me. I moved up here from county where there wasn't emissions testing at all. I just want "to set it and forget it", if you will, I dont want to have to change out from CC to test pipe and back every other year. But I'll see, Thanks for the suggestion!

 

Thanks for your input Nick, where did you get your test pipe from?

 

My cat on my old exhaust was a Magnaflow. It was from a previous owner, and after owning it for 3 months myself, the honeycomb inside came loose.

I ordered another one right before inspections, and soon after I passed, this one did the same.

I popped it off, gutted it, and reinstalled it. I put a 90 degree elbow defouler on it and have been fine ever since.

The magnaflow just kept falling apart on it for some reason. From the outside, it looks perfect, so no worries...

 

It should be a universal fit, its the same threads as a spark plug, I've used it before, it works like a charm for less than $10

Using it just spaces your o2 sensor far enough out of the exhaust gases that the sensor is fooled into thinking it contains less pollutants

 

This is what I did. You should be able to use any test pipe that has an o2 bung. Check what your emissions laws are for sure. For me m exempt cause I drive my car less than 5k a year. But even if I didn't id be ok cause all they do here is a gas cap check and fault scan. The logic is if the lights not on there's no issue so they don't do a visual on OBD2 cars.

 

I agree with Vegas...

It's expensive to rebuild any oil burning/cat clogging motor, even my other Integra's b18b1 motor.

I searched e-bay for ...angled o2 .....($25 for one that doesn't rust) linky

http://www.ebay.com/itm/304-Stainless-Steel-O2-Oxygen-Sensor-90-degree-18mm-test-pipe-extension-18mm-02-/251317422571?pt=Race_Car_Parts&hash=item3a83af89eb&vxp=mtr

For the inspection, I bought a used cat for $150, on Honda-Tech.
(Drive it ten miles to allow the ecu to save some info, for the obd2 emissions tester.)

I gutted my clogged OEM cat, installed the angled o2 adapter, and reused the donut after I passed the inspection.


Note...get the donut gasket that has the wire mesh (like a screen door) wrapped around it and you can reuse it on your gutted cat.

 

I had the same code, then bought a new manifold and cat, put it on passed emissions, then the code came back 2 weeks later! I have no idea what to do!