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Acid bath and P0420

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

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  1. JC91006

    JC91006 Senior Member

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    If this works, this would be a good alternative to the $2000 that dealers charge. But I'm sure it's a band aid, like a rebuilt battery. I just want to know how long it'll last.
     
    #21 JC91006, Jun 8, 2016
  2. sorka

    sorka Active Member

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    That's the real question. If the cat has degraded due to overheating, then this won't help. If it's a combination of overheating and the surface being coated with metals contaminants then it would help some. In theory if the failure was due only to contamination, then following the procedure as outlined in the study would fully restore the cat.

    I did not follow the procedure exactly as I didn't have constant flow nor did I heat the water up to 150F. It started out at 115F and pretty much stayed there because it was in a black container out in the sun for the 6 hours.

    Here's an interesting forum post:

    (All Years) Catalytic Converter Citric Acid Bath P0420 - Subaru Forester Owners Forum
     
    #22 sorka, Jun 8, 2016
  3. JC91006

    JC91006 Senior Member

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    We have another member that has a p0420 and doesn't seem to want to spend money to fix it.......this would be a good solution (LOL) for him.
     
    #23 JC91006, Jun 8, 2016
  4. JC91006

    JC91006 Senior Member

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    I wonder if the science has to be exact? Or if you can simplify it by saying, 1 pint of acid mixture to 1 gallon of water......for the people that are bad at math
     
    #24 JC91006, Jun 8, 2016
  5. sorka

    sorka Active Member

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    I think it needs to be close. If you don't do enough, safer, you'll get fewer miles before the efficiency falls below threshold again. If you go too far, you remove too much of the catalyst material. Think of the catalyst as a layer of clearcoat. If you get a scratch that isn't deep, it can be buffed out and the clearcoat is shiny again serving it's purpose. If you go to far and etch too much depth out of it, you've gone all the way down to the paint and ruined it.
     
    #25 sorka, Jun 8, 2016
  6. sorka

    sorka Active Member

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    Another 130 miles today and still no DTC.
     
    #26 sorka, Jun 9, 2016
  7. sorka

    sorka Active Member

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    Another 90 miles today and still no P0420 :)
     
    #27 sorka, Jun 9, 2016
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If you have driven 360 miles since the bath without issues, then I would say this is a reasonably long-term fix. At least as long as the benefit provided by the traction battery "rebalancing" concept... :cool:

    What color was the acid bath prior to dipping the cc into it? Did the ash deposits visible in the cc disappear after the bath?
     
    #28 Patrick Wong, Jun 9, 2016
  9. sorka

    sorka Active Member

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    Yes, the honey comb looked completely clean and like metal after the bath. The 8 gallons had a green tint to it after 6 hours.

    520 miles and counting.
     
    #29 sorka, Jun 10, 2016
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  10. Former Member 68813

    Former Member 68813 Senior Member

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    this is so frigging cool. thanks for posting!
    even though your oil consumption is low, i would personally do a piston soak to fix it before it gets worse. google for piston soak or send me a PM.
     
    #30 Former Member 68813, Jun 10, 2016
  11. sorka

    sorka Active Member

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    650 miles since the bath and still no ECL.
     
    #31 sorka, Jun 12, 2016
  12. JC91006

    JC91006 Senior Member

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    I've figured out the simple formula for this solution, to mix a 9 gallon soak.

    Based on the information on the video provided, but using nearly pure citric acid and oxalic acid (both on Amazon).

    use 1.5 lbs of pure citric acid powder and 1lb of pure oxalic acid powder. That is pretty close (not exact) to what the formula requires for about 9 gallons of soaking solution.

    Who wants to get a group buy going on 5 batches of this stuff?? LOL I think that'll be about $5 per batch. Now only if I can find a container that will hold 9 gallons of this stuff without spilling over.
     
    #32 JC91006, Jun 24, 2016
    Last edited: Jun 24, 2016
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  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    A rubber trash can?
     
    #33 Patrick Wong, Jun 25, 2016
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  14. JC91006

    JC91006 Senior Member

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    good idea, I have 2 of those kitchen cans around too. I'll be ready to test on Monday
     
    #34 JC91006, Jun 25, 2016
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  15. Former Member 68813

    Former Member 68813 Senior Member

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    why 9 gallons? How about a smaller amount?
     
    #35 Former Member 68813, Jun 25, 2016
  16. JC91006

    JC91006 Senior Member

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    The op used 8 gallons so I tried to get measurements close to 8. I don't know if 4.5 gallons would be enough liquid to soak the entire cat. I just wanted an easy formula. 4.5 gallons would still be easy, just not sure if it's enough
     
    #36 JC91006, Jun 25, 2016
  17. sorka

    sorka Active Member

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    2000 miles now and no ECL. I was going to smog it today but my wife didn't get home in time before the place I usually goto closes. The only places open tomorrow, Sunday, are more expensive than the places that are only open Monday through Saturday. So I might have to wait until next saturday.
     
    #37 sorka, Jun 26, 2016
    Last edited: Jun 27, 2016
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    What is ECL? Did you mean the check engine light has come back on?
     
    #38 Patrick Wong, Jun 26, 2016
  19. sorka

    sorka Active Member

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    Sorry. That was a typo. It's supposed to be NO, not NOW.

    2200 miles and no ECL.

    I smogged it this morning. It's not due until 9/22. DMV should be mailing out the renewal in 3 weeks.
     
    #39 sorka, Jun 27, 2016
  20. sorka

    sorka Active Member

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    2300 miles. Still looking good. So on Sunday, I went to the DMV website to pay my registration. It was early, like 88 days before it's due. It said that I was not eligible to renew online. It was about 3.5 weeks before they would have mailed out the renewal anyways. I smogged it Monday morning. This morning, two days later, I tried again on the DMV site and it let me renew!!!!!!

    So I'm officially past the the scare. A $20 acid bath saved me $1800.
     
    #40 sorka, Jun 29, 2016
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