O2 Sensor in 5 Hours?

[truckster]

So, here's how I spent a significant chunk of my New Year's Day: My daughter has a 2005 Subaru Outback. Her emission test is due in January and she had a check engine light on. I scanned it and came up with P0420 - bank 1 sensor 2 catalyst below efficiency threshold. No problem, right?

Well, to start off with, this is a California emissions car, so there are 3 catalytic converters and 5 O2 sensors. It should be the one behind the first cat on the right (passenger side) bank, so I get the right sensor, put it up on ramps, and go to work, thinking 30 minutes at most and maybe as quick as 15.

First, the connector is right up against the wiring harness. It takes me more than 15 minutes just to get it in a position where I can release it. So far, not so good.

Then I get under the car with my O2 sensor socket and 3/8 drive ratchet. The O2 sensor isn't budging. After a liberal application of Liquid Wrench, I put a cheater on the wrench and try again. No luck. I get out my torch and give it a nice blast of heat and try again. No luck. I mean, it's not even budging a hair. I keep going between the penetrating oil and the heat, making my garage and me smell divine, until the wrench finally moves. Nope, it's not loosening; the hex on the sensor rounded off.

Now the exhaust manifold and pipe have to come off. Because it's a CARB emissions car, the two pipes come into a Y just ahead of the third converter. There's barely room to get a wrench in there, but it doesn't matter, because road debris has damaged the nut to where a wrench won't hold it. So I get out the angle grinder. One of the two bolts falls quickly. The other one is tucked tightly in the Y, so I get out the Sawzall. Nope, can't get in there. I get out the Dremel and manage to cut about 2/3 of the way through, but there's not enough room to continue. So I have to get out the plasma cutter, and I somehow manage to get the plasma stream in the right place and remove the pipe. I really need a lift...

So now I just have to get the O2 sensor out. My first attempt is to hammer a socket onto the sensor and hit it with my impact wrench. It starts spinning and the end of the wire spins around and hits me in the arm and in the thigh. Ouch; I should have cut that off first. No matter, because now the hex is really rounded. So I take the angle grinder and cut large flats on opposite sides. I get an open-ended wrench on there, but it's not moving. Next up, a pair of very aggressive vise grips with V-shaped jaws and a long cheater pipe. I give it more heat and more juice, but it's just removing more material...

Now things are getting desperate. I decide to cut away everything above the base of the sensor. Did you know that the core of an O2 sensor is made of zirconium dioxide, which is only slightly less hard than diamond? I finally cut through it with my angle grinder after going through a couple of cutoff wheels and sending bits and pieces of grinding wheel and zirconia all over. I then take a 3/4 inch nut and weld it on my highest heat setting, making the thing glow bright red, almost white. Now I've got something to put my impact on, and the remnants of the O2 sensor finally come out.

Now I get to go to the auto parts store, because I need some exhaust gaskets that I hadn't planned on replacing. Most of the reassembly goes well, but I discover some broken grounds that I repair while I'm under there. Finally I clear the codes and hope not to see the underside of that car for a good, long while. By the way, did you know that all Subarus leak oil from almost every conceivable seal and gasket?

So that's how I spent my New Year's Day afternoon. How was your day?

[RustyPile]

My day wasn't quite as conflict filled as your.. I couldn't remove the lid from a new jar of pickles, so I engaged the help of my wife's electric powered lid remover.. That didn't work either. So after attacking this jar lid for about 10 minutes, I put the jar of pickles in the fridg.. I then got comfortable in my favorite recliner. My old dog Harley, jumped into my lap and we both took a nap...

[yuccales]

Originally Posted by truckster

So that's how I spent my New Year's Day afternoon. How was your day?

Way better then yours! Fixed front gate latch with no problems, changed oil and test run the Generac, no problems, cleaned and waxed my top, bottom, side boxes. Helped my wife rearrange her "she shed". No cussing, no Band-Aids! Truckster, we all have had projects take a turn for the worse like yours today. Never any fun. Your daughter is very lucky to have a dad like you to help her out. Well done!

[Sheepdip]

Makes these old, antiquated trucks we drive quite a pleasure to work on, even in their more difficult times.

[leddzepp]

With a po420 code there’s a good chance the catalytic converter is toast and changing the o2 sensor will not fix it. I hope that’s not the case here.

[Steeveedee]

That's a pretty sucky chain of events. Looks like setting it on fire would have been a better option. I'm on a low-level search for another old vehicle so that I can avoid your scenario, Truckster, because I'm not going to be able to do it. Ever try washing a car, hobbling on a cane? Last time I took my econobox to the robo-wash it busted the shark fin antenna off. Can't do the work- drop the headliner, etc., because of arthritis. Just under $600 to replace the antenna. I honestly don't know what I'm going to do, but I'm thinking that another old vehicle will be less of a problem. Antenna busted off? Don't listen to the radio, anyway, but a fender-mounted antenna won't leak water in, either. Well, not much...

[truckster]

Originally Posted by leddzepp

With a po420 code there’s a good chance the catalytic converter is toast and changing the o2 sensor will not fix it. I hope that’s not the case here.

I've had good luck changing the O2 sensors for the P0420. If that doesn't work, it's probably going to get a spark plug anti-fouler. The cat is expensive.

[Boog]

Originally Posted by truckster

So, here's how I spent a significant chunk of my New Year's Day: My daughter has a 2005 Subaru Outback. Her emission test is due in January and she had a check engine light on. I scanned it and came up with P0420 - bank 1 sensor 2 catalyst below efficiency threshold. No problem, right?


So that's how I spent my New Year's Day afternoon. How was your day?

This looks to be a good place to insert this;
"all 20 minute jobs are 1 broken bolt away from a 4 day ordeal"

[leddzepp]

Originally Posted by truckster

I've had good luck changing the O2 sensors for the P0420. If that doesn't work, it's probably going to get a spark plug anti-fouler. The cat is expensive.

Yes those work great, but it will fail the visual inspection and they will call you out on it. Best way to avoid that scenario is clear the code right before you take it for inspection (without the anti fouler installed). It will obviously pass the visual, but will “fail” the diagnostic because the computer will not have any recent data. The inspector will tell you to drive the car for about a week and bring it back. Install the anti fouler in the meantime, then take it back for the diagnostic portion. The visual will have been done and they won’t look at it again, and it will pass the diagnostic portion.

[72c20customcamper]

I had to replace the second cat in my Tacoma because of the P0420 code . Used to be able to clear it and drive it till it reset then inspect the truck. This time it would throw the code as soon as it reset. My 12 Nissan has one of these in it . No visual inspection of components here just plug it in and if it passes your good to go

[72c20customcamper]

And I had to have the aftermarket cat sent to my brother in law . In NY you can only buy factory or CARB cats . At 3-4 times the price of an EPA certified cat .

[jerry moss]

Originally Posted by leddzepp

With a po420 code there’s a good chance the catalytic converter is toast and changing the o2 sensor will not fix it. I hope that’s not the case here.

correct, a P0420 code means the sensor is working-well was working- you need a new catalytic converter. i work in a muffler shop and it's common for people to replace the sensors first-google says so i guess-then clear the light and drive the car to run all the monitors and bingo cat code comes back.

[truckster]

Originally Posted by jerry moss

correct, a P0420 code means the sensor is working-well was working- you need a new catalytic converter. i work in a muffler shop and it's common for people to replace the sensors first-google says so i guess-then clear the light and drive the car to run all the monitors and bingo cat code comes back.

That's weird; my live data showed the O2 sensor was flat. I guess we'll see tomorrow when it goes for its emissions test.

[jerry moss]

Originally Posted by 72c20customcamper

And I had to have the aftermarket cat sent to my brother in law . In NY you can only buy factory or CARB cats . At 3-4 times the price of an EPA certified cat .

i guess they don't check for the E.O. number on the body of the cat where you live, in commifornia the smog tech is required to verify that the E.O. number is correct for the vehicle it's installed on on any aftermarket cat. the cheapo fed cats do not have an E.O. and it's an automatic failure out here. i hear the same B.S. all the time at the shop-i can buy it online for a hundred bucks- i tell them good luck come smog time cause it will fail if the smog tech does his job correctly.

[truckster]

Here they just plug into the OBD port and if the computer is happy you're good to go.

If you have an address outside of the densely populated counties, no emissions test is required.

[jerry moss]

Originally Posted by truckster

Here they just plug into the OBD port and if the computer is happy you're good to go.

If you have an address outside of the densely populated counties, no emissions test is required.

out here the smog tech has to check any aftermarket part for the E.O. numbers and go to the state/BAR website to verify if it's legal for that particular vehicle. it's a pain in the a$$.

[57taskforce]

Damn I’m so glad I don’t have to deal with emissions or vehicle inspections any more. Some of this stuff has gotten so insane.

[72c20customcamper]

Originally Posted by jerry moss

i guess they don't check for the E.O. number on the body of the cat where you live, in commifornia the smog tech is required to verify that the E.O. number is correct for the vehicle it's installed on on any aftermarket cat. the cheapo fed cats do not have an E.O. and it's an automatic failure out here. i hear the same B.S. all the time at the shop-i can buy it online for a hundred bucks- i tell them good luck come smog time cause it will fail if the smog tech does his job correctly.

No visual check of components here just plug in the OBD and if it’s good then it passes the emission test . Here when a vehicle hits 25 years old they no longer test for emissions just a safety . The Toyota has one more emissions test in 2017 then it’s safety only . But really not many everyday vehicles reach 25 years old here they rot away well before that .

How much is the inspection in California? Here a full inspection emissions and safety is $21 my Dodge diesel over 8500 GVWR is $15 and no emissions test my old cars are $12 . Motorcycle is $6

[Rich84]

My brother in-law owns an exhaust shop. People come in with vehicles skipping and running crappy. The unburned fuel ruins the converter. They argue with him that it only needs a converter. He politely asks them to leave his shop and go see a mechanic first.

[Steeveedee]

SMOG check where I'm at is $58. No more dyno, they just plug into the diagnostic port. No failure codes, you're good to go. They do look things over. One year, the tech said I had a vacuum hose that looking soft and would likely fail next time. I replaced any hoses that looked like they needed it after that.