[topheavy]

2002 non supercharged, 4wd 5speed, & not sport edition.

Possibly helpful background info
Two oil changes ago I had a K&N air filter installed because a friend recommended it. I have no cleaned it since and am on the verge of my third oil change (horrible). Few days ago the CEL came on as I drove up a steep hill at about 3k RPMs with no extra load & not pulling anything.

CEL on and tested at autozone
PO328, PO430. Knock & O2 sensor, if I'm reading report right.

Ok. Should I get more specifics on which O2 sensor(s) and replace? Is there a way to test the sensor? Or is it possible that all of this is because the air filter might be horribly dirty? (From other threads I understand I do not need to replace knock sensor)

Thanks

*Edit- After undoing the four latches holding the K&N air filter, do I need to undo the four bolts keeping the filter top/cap attached to the air flow piping? - I don't know the appropriate jargon.

 

[soccerbrace]

You probably have about 5 or 6 more oil changes at minimum left before you have to clean the filter. All you do is unlatch the box half, lift up, and pull out firlter.

Yes you can test the 02 sensor, but it is bad, and I consider replacing the 02 sensor as routine maintenance. You need more specifics to find out wich o2 sensor it is because there are 4 or them.

 

[topheavy]

Ahh ok. I read a thread recently on here about using the gas pedal in a pattern to find out the error code exactly. I suppose I can use that and then look up the code to find out which sensor it is.

I have a readout from Advance Auto Parts but it doesn't say which sensor.

 

[Lucky13]

P0430 - Catalyst System Efficiency Below Threshold (Bank 2)
click the links for more info.. there is a good possibility that it isnt your O2 sensors..

knock/O2/air fuel ratio issue

 

[notstock4long]

That is the downstream passenger side O2 sensor, but like he said, it could be something else. I currently have the same code, and still need to figure out what it is as well.

 

[topheavy]

This winter I have made nothing but short trips around town from cold starts, which never gave the Cat time to warm up and enter the "closed loop" where pre-cat O2 sensors can actually do their job.

I have had the vehicle over a year (in college) and have been making mostly short trips (i'm not commuting to work anywhere; walk to school). So I think the condition became worse over the winter.

http://www.picoauto.com/applications/lambda-sensor.html
-third paragraph from bottom of page.

I think it mostly ran rich then in the "open loop" system, which fouled up some of the O2 sensors (not sure which ones).

What do you guys think?

 

[Lucky13]

if you have a multi-meter you can test your O2 sensors. check my post #4 second link..

P0430
"The most common cause it the three way catalyst converter Bank 1."
Possible causes
- Three way catalyst converter Bank 2
- Exhaust tube
- Intake air leaks
- Fuel injectors may be faulty
- Fuel injector leaks
- Spark plugs may be faulty
- Improper ignition timing
- Engine Control Module

 

[topheavy]

I can go buy one and test them then. Is there a way to test and see if I need a new catalytic converter? (maybe o2 sensors and are fine and it needs replacing..?)

 

[Lucky13]

there is no good way to test a cat to see if its bad..

you could cut it in half to see how clogged it was, but then its useless..

you can use specialized emission testing equipment like what the state uses.
pressure/vacuum test and gauges with it off the truck.
and possibly even a flashlight into the core,which is the most practical but still pretty inconclusive. unless you see pieces floating around inside...
http://www.all-catalytic-converters.com/techtip1.html
http://www.all-catalytic-converters.com/techtip2.html

 

[nismo1982]

If the ECM is storing that code then its most likely a bad cat... also exhaust leaks before the rear 02 may cause a catalyst code. The ECM thinks the cat isn't storing oxygen as the exhaust passes by the 02.

 

[nismo1982]

One way to test the catalyst is by temperature. Get an infrared temp gun and compare the temperature of the front and rear of the cat at operating temp. The rear should be much hotter then the front due to the chemical reaction within the cat. Good luck.

 

[topheavy]

If the ECM is storing that code then its most likely a bad cat... also exhaust leaks before the rear 02 may cause a catalyst code. The ECM thinks the cat isn't storing oxygen as the exhaust passes by the 02.

Can you be more specific about exhaust leaking? Like a hole in the pipe somewhere? Or leaking something it shouldn't out of the pipe's end?

Thanks

 

[topheavy]

Had fuel/air induction system service done on it (decarb). Seems to have cleaned catalytic converter , amongst other things, up well enough to solve the problem. Thanks for all the responses.