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Acid bath and P0420

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by sorka, Jun 7, 2016.

  1. JC91006

    JC91006 Senior Member

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    well you're good for 2 years

    I got all my chemicals today to do this. Bought citric and oxalic acid in powder form.
     
  2. sorka

    sorka Active Member

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    At least on needing to smog it. In two years, I'll have another 75K miles on it (300K). I wouldn't be surprised if I have to deal with the traction battery by then.

    I also wouldn't be surprised if the P0420 returns before then as well.
     
  3. sorka

    sorka Active Member

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    This is the container I used. It's narrow and tall which is why I was able to get away with 8 gallons.

    [​IMG]
     
  4. JC91006

    JC91006 Senior Member

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    I would think 8 gallons would fill that all the way up to the top
     
  5. sorka

    sorka Active Member

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    About a third of the way. I guess I should have taken the shot with something for scale.
     
  6. sorka

    sorka Active Member

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    I take it back. It's about 1/2 way. Also, a 5 gallon painters buck *might* be tall enough to do it but just barely. I had hadn't thought about that because the container I had was black and I knew it would keep the water warm in the sun.
     
  7. JC91006

    JC91006 Senior Member

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    did you have to wear gloves for this project?
     
  8. sorka

    sorka Active Member

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    I did. I think it's a good idea. I also wore eye protection on the off chance anything splashed in my face.
     
  9. sorka

    sorka Active Member

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    Well drat. I got the P0420 again. It lasted about 3K miles.

    Possibilities:

    1) The acid bath did nothing it was the actual washing it clean that allowed it to work well enough for a while. I'm going to repeat this in about 2 years to see if I get the same result just from cleaning.

    2) The acid bath worked a little but since i wasn't running the water continuously nor did I have it at the 150F that the study cited, I didn't get anywhere near the surface etching required to remove the contaminant metals. It could very well be that it worked well enough for what I did that it was on the threshold of throwing the code over the last 3K miles but squeaked by. I reset the code 200 miles ago and it hasn't returned, so if I get another couple thousand miles out of it again doing nothing, then I'll assume that the acid cleaning worked but that I didn't do it as completely as I should have having skipped steps and conditions cited in the study.

    3) A combination of both 1 and 2.
     
  10. JC91006

    JC91006 Senior Member

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    At least you got your smog check done last week
     
  11. sorka

    sorka Active Member

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    OK, another 500 miles since getting the P0420 and it hasn't returned yet. This leads me to believe that the original bath restored the cat to a barely sufficient efficiency level. For sure next time I'll be doing the full treatment at the correct temperature and flow rather than just having it sit. I did stir it every 30 minutes or so but that's not the same as constant flow. And 120F is not the same as 150F.

    Got my sticker yesterday in the mail :)
     
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  12. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I'm wondering how you would maintain 150 degrees F for an extended period, considering the relatively tonic nature of the acid bath.
     
  13. jichi

    jichi Junior Member

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    I am having the same problem it just happened after I changed my spark plug and I broke ceramic piece from spark plug number four and did not know it until I drove the car start getting misfire then got that taking care of. The next day I start getting Misfire again and P420. I found that my wiring got lose inside near the cabin filter fixed that no more misfire then now get P420.

    MY question is can you check the temperature for Bank 1 sensor 1 and bank 1 sensor 2(before and after cat coverter O2 sensor). I mine is showing the following

    IMG-20160712-WA0000.jpg

    As you can see Bank 1 sensor 1 showing 1080F Bank 1 sensor 2 showing 859.
    I read on the internet Bank 1 sensor 1 temperature should be less than Bank 1 sensor 2. if not then you got restricted cat.
    I am not sure if you have to have the custom PIDs with full version of Torque in order to see these parameters.

    I would really appreciate your input. Thanks
     
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  14. MattStevenson

    MattStevenson Member

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    I got away with just putting in an O2 sensor spacer years ago. That was in TN though and the testing facility isn't owned by the government so I wasn't worried about getting a ticket or anything.

    Posted via the PriusChat mobile app.
     
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  15. SFO

    SFO Senior Member

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    Any updates?
     
  16. MsHeatherGrace

    MsHeatherGrace Junior Member

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    Don’t suppose anyone has a video link to a complete “how to” on this? The more thorough the better. I’ll most likely need all the tools except the socket set perhaps. I’m guessing I should get two O2 sensors also. Going to try to clean it myself… Desperate times & all that.

    Made plenty of home repairs, but never any on my car. I’m pretty intimidated, but smart enough that I *have to* at least give it a shot.

    Questions:
    • Got any advice on the best place to get the tools, ramps & such? Do you think I need a PB blaster, whatever that is? Where do I get O2 sensors (is it a dealership thing)?
    • What sort of machine gives you those read outs w/ status of different aspects of system being green/good vs red? Is it an ODB2 scanner or ?
    • ANY OTHER TIPS?

    Thx everyone, much appreciated!
     
    #56 MsHeatherGrace, Aug 5, 2021
    Last edited: Aug 5, 2021
  17. tacopyro

    tacopyro Member

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    i have a 08 Prius II that has P0420 going in and out. i bought this car used. i figured the cat was dying with all the oil consumption it had. but what i didnt know was the O2 sensors was also going bad. i was looking at techstream and it seems that i had a lazy O2 sensor. when i took it out. it was coated in some white powder. AMZ has the Denso O2 sensor 234-4623 for 40++ so i gave it a shot and so far it stopped my P0420.
    i also gave it a shot of catalyst cleaner by solderit that i had lying around for years now. you could give that a try.

    i tried doing the oxalic citric acid procedure. i bought a aquarium pump. and a water heater that looked like a spoon and a temp switch regulator which controlled the heat. i ran it 24 hrs and i ran it twice on a cat i was trying to save but i guess it was too far gone and i couldnt. but i had a choice of getting aftermarket cats with that car that are not possible with our Prius.

    i recently learned that our Cat is basically a O2 storage device. and what the ECU is measuring is how long the O2 Storage will last in a given condition. unit in seconds. for my 2008 gen 2 prius, the minimum required is 0.031 seconds to a max of 9.993 seconds. Cleaning the cat and putting in a new O2 sensor helped changed mine to pass with 0.038. i am going to attempt to clean the cat again to see if it will improve further in the future.
    >> here << is the video that helped me understand. i hope you will too.
     
    #57 tacopyro, Aug 9, 2021
    Last edited: Aug 9, 2021
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  18. ChapmanF

    ChapmanF Senior Member

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    Good job finding that monitor test value. Gives people a more sensitive and useful way to see how much good the cleaning did, compared to just "did the P0420 come back?". (y)
     
    mr_guy_mann and tacopyro like this.
  19. tacopyro

    tacopyro Member

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    an update on my 08 with P0420. i recently sold it to my son and he already racked up 6k mi. since.
    He recently had a P0101 (MAF) and a P0420 again. I cleaned the MAF and code went away but the P0420 was still there.

    Since the last post. Forget the acid bath. i found "cataclean" and have been using it to easier good results.
    Make sure to fix all the underlying conditions of the other codes first. then whatever is causing the P0420 before using it. sometimes fixing those first makes the CEL go away.

    But if after fixing and P0420 is still there, check your techstream and see what the O2 Storage B1 value is. (pictured in this thread). Take note of the value and reset the CEL, Add a liter of cataclean to half a tank of gas and then drive a minimum of 15mins or more (need to get the Cat hot!), even a few drive cycles of 15mins minimum until you are almost empty. hopefully CEL didnt come back. if it does or it doesnt (fixed), check your techstream again and note the O2 storage value and see if it improves.

    I had to do mine twice because i didnt fix the P0101 on the first round. checked all the O2 related stuff and they are ok. Son passed smog after that with a O2 storage value of .044. it was 0.030 before. and 0.031 is the minumum value :ROFLMAO:. i think i can make it go higher if i keep dosing it at half tank...

    On the product itself. i felt that their single use bottle 16.7oz ($25!!!) was so expensive for what it does. Then i found they have a 3 liter ($33) and a 5 liter ($50) and that made it so much better! so far i also fixed my old Tacoma and my 2 other 3rdG Prius with it. CEL hasnt come back yet!
     
    #59 tacopyro, Mar 16, 2022
    Last edited: Mar 16, 2022