OEM and Aftermarket Catalytic Converter emissions

Discussion in 'Gen 2 Prius Technical Discussion' started by TMR-JWAP, Jan 16, 2021.

  1. TMR-JWAP

    TMR-JWAP Senior Member

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    The test equipment is a COSA 707. It's a 7 gas emissions analyzer for industrial combustion processes . It's not exactly optimized for automobile emissions, but it's also not a cheap device and should at least allow us to compare OEM catalytic converters to some aftermarket cheapos. It's set on diesel, because it's the closest option. Doubt it makes any difference.

    I'm not going all crazy with trying to analyze a million different scenarios. This test was performed on a recently purchased 275k mile 2008 Gen 2 with a converter assembly that was replaced a couple years ago due to a P0420 code. I got home from work this morning (driving my 2007), fired up the 2008 and cranked the heat to max, in manual, with all the windows down so the car would run continuously. I also fired up our 2004 Santa Fe 3.5L (ICE, no hybrid) Went into the house, fed the pets and made breakfast. Then went back outside to the 2008, still running and now warmed up. Insert the sample line into the exhaust pipe and here you go...was interesting to see the CO measurement was moving around a bit.
     

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    #1 TMR-JWAP, Jan 16, 2021
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  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Then I walked about 100' to the Santa Fe (3.5L ICE) and after allowing the COSA to breathe clear air for a while, stuck the sample tube into the Santa Fe exhaust.....rock steady. The NO readings were moving between 2 and 6 ppm.
     

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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Went back to the 2008 Prius because I realized I didn't check NO and did a bunch of quick photos to show the CO cycle. Interesting that the CO drops until the O2 reaches 0, then the CO comes back up fast. Imagine that, no O2 to combine with. But, the NO readings stayed on zero. Must be something in the ratio control circuit cycling. Here's a bunch of photos.

    IMG_8616.JPG IMG_8617.JPG IMG_8618.JPG IMG_8619.JPG IMG_8620.JPG IMG_8621.JPG IMG_8622.JPG IMG_8623.JPG IMG_8624.JPG IMG_8625.JPG IMG_8626.JPG IMG_8627.JPG IMG_8628.JPG IMG_8629.JPG IMG_8630.JPG IMG_8631.JPG IMG_8632.JPG IMG_8633.JPG IMG_8634.JPG IMG_8635.JPG IMG_8636.JPG IMG_8637.JPG IMG_8638.JPG IMG_8639.JPG IMG_8640.JPG
     
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  4. TMR-JWAP

    TMR-JWAP Senior Member

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    And then I went over to my 2007 daily driver (which had been running for over 10 minutes, set up just like to 2008) with the $114 dollar catalytic converter from ebay...................the first and last couple photos were with the sample line in fresh air

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    Yeah....I don't think I'm going to lose any sleep over the aftermarket converters.....
     
    #4 TMR-JWAP, Jan 16, 2021
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  5. TMR-JWAP

    TMR-JWAP Senior Member

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    And then....I went back to the Santa Fe for another round. Here's a bunch of photos. You can tell if it's sampling or not based on the gas temp. Some photos show after I take the tube out, just checking that things go back to standard atmosphere readings.

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    .
     
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  6. Paul Schenck

    Paul Schenck Active Member

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    Just what I found


    iPhone ?
     
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  7. PriusCamper

    PriusCamper Senior Member

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    So you're basically saying that a brand new cheap $130 after market catalytic converter is equivalent to what they made 15 years ago as OEM for Prius and in some cases the newer one is slightly better at cleaning emissions?

    Is that the conclusion I'm seeing in all these pictures?
     
  8. TMR-JWAP

    TMR-JWAP Senior Member

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    We have to keep in mind these measurements were taken only at idle. For all we know, 70 mph on the highway may be enough flow volume to overwhelm the cat. I'm far from an exhaust expert but I like that even the aftermarket cat had 0 on the NOx, while our completely stock, and decently maintained, Santa Fe didn't. So, on initial impression, it seems to at least be as good or better than an early 2000s ICE setup.

    Also, none of the aftermarket cats I've installed have thrown any codes yet. I've had my 2007 at maximum throttle position many times (aahem...electrically limited), so if that didn't overwhelm the cat, a mere 70 mph certainly wouldn't.
     
    #8 TMR-JWAP, Jan 20, 2021
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  9. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    How do they test these vehicles behind the tinsel curtain?
    Do they run them at idle or is there a set RPM that they use???
    Perhaps a dyno?
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    It's been decades since I've lived in a state that does annual inspections, but I seem to remember having an idle sniff performed and then one of the techs pulling my car onto a set of rollers a few times.

    It wouldn't surprise me if the roller tests have fallen by the wayside considering all the self monitoring newer cars perform.
     
  11. mr_guy_mann

    mr_guy_mann Member

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    Your 2008 has some kind of problem- the CO and O2 shouldn't noticeably cycle like that. Likely that the AF sensor or the downstream O2 sensor is deteriorated (I don't know when Toyota switches from normal fuel control (using the AFS) to "rear fuel trim" (using the O2).)

    You might be able to see it cycle if you graph the short term fuel trim- it should close to 0% (maybe somewhere +5 to - 5), but sitting at idle- whatever the number is, it should stay within a 1% range. ie 0 to 1, or - 1 to - 2, etc. I often see less than 1% cyclic range.

    Unless there is something drastically wrong, you will never see any significant levels of NOx emissions from a gasoline engine at idle. You need lots of heat and pressure (in other words LOAD) in order to get nitrogen to react during combustion.

    If you want to really see how the catalytic converters compare, you can use a scantool to perform a Oxygen Storage Capacity test, just like the ecm does. Get the engine and cat good and hot. Now open the special test that adjusts fuel trim percent - you also want to view or graph the data for the AF sensor and O2 sensor voltages. Normal voltage is around 3.3 for AFS and 0.7-ish for O2. Select +25% trim and AFS should go to 2.5 or less (rich) and O2 of 0.9 or more. Right now you are using all the oxygen in the cat. Select - 12% trim and watch the voltages (graph the data or video it so you can time what happens). First the AFS should hit 4.0V or more (lean), now you time how long it takes before the downstream O2 sensor switches to under 0.1V. A good cat will grab and store more oxygen and takes longer (6 to 12 seconds) before the O2 sensor changes. 4 seconds is kind of marginal. 2 seconds or less will fail - P0420.
    The only caveat is I usually use my Snapon scanner to do this as it will let me only display the AFS and O2 data pids- which speeds up the frame rates and makes the test more accurate. I haven't tried it on techstream to see how well that would work.

    Posted via the PriusChat mobile app.
     
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  12. PriusCamper

    PriusCamper Senior Member

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    Any chance you or someone else reading this could do this test?
     
  13. mr_guy_mann

    mr_guy_mann Member

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    In NewJersey they had dyno tests just long enough to validate that OBD2 actually worked (til early - mid 2000s?) then dumped that. They kept idle sniffer tests for 95 and older until a few years ago- now those cars are emissions exempt. Everything now is just OBD2 plug-in and visual inspection done every two years.

    Posted via the PriusChat mobile app.
     
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  14. TMR-JWAP

    TMR-JWAP Senior Member

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    conveniently enough, irt emissions testing, NJ is the exact state I was referring to. Toms River HS North, Class of '85...…and never stayed in the state for more than 2 weeks a year after graduation……...

    I agree with you on the 2008.
    I merely did this to throw some quick data out there for everyone questioning the viability of aftermarket catalytic converters. I don't have the time or proper equipment to do full boogie testing. It would be great if anyone that has better (or proper) equipment and spare time could do additional testing and add the data to the discussion.

    The 2008 needs some work. The car is cosmetically very, very good and was taken to Sparks Toyota every ~5k miles. I just printed out the full maintenance history yesterday. 55 service records and the car has exactly 275k miles when I bought it. In Jan of 2017, the car was taken to the dealer and diagnosed with a P0420. Prices were quoted, etc, but appears work may have been declined. Write up was not as clear as I would have hoped, but there's no mention in any follow-on service records of the code returning (~40k miles added to odo since code was cleared). I will likely do an identical check on this car again after installing the aftermarket cat to see if it causes any changes.

    The final service report 8/20 states a C1345 is present, would not clear after a relearn was performed, needs abs actuator replaced, needs front brakes, rear brakes and water pump replaced. When I techstreamed it, I showed a C1345 and C1368/505. Historically, a bad combination, but I haven't had time to really get into it yet. There's no doubt about the water pump, it sounds horrible. I can't believe it survived the drive from Myrtle Beach to Columbia. First thing I did on the ay out of MB was stop and get a gallon of coolant and 3 gallons of water just in case. A few things I want to try before replacing the abs actuator, but that replacement is fairly likely to happen. I figure I'll verify the brakes, refresh anything that needs it, to a good bleed/flush and try the relearn again. If it's a no go, then actuator.
     
  15. mr_guy_mann

    mr_guy_mann Member

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    I just went and tried this test on my 2006 and dang... I "forgot" how difficult it can be to keep the engine running when it doesn't want to. I use this test often on normal Toyotas and it's easy. I did it once on another Prius but I must have caught the HV battery just right to keep the engine idling. Right now my 2006 will shut off. Give it enough throttle to force the engine on and it runs at 1500-1700 rpm - that's a bit too fast to get a good result (the switch points occur much faster). Let off the gas just a bit too much and it shuts off. AFAIK you can't use inspection mode AND perform the Air/fuel ratio adjust test at the same time. Nice idea but I guess it doesn't work for this. Oh well.
     
  16. SFO

    SFO Senior Member

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    Turn on the AC or crank the heat up, one or both should keep the engine on for a bit.
     
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  17. Adebrettski

    Adebrettski New Member

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    Which aftermarket cat are.you using if you don't mind me asking?
     
  18. TMR-JWAP

    TMR-JWAP Senior Member

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    I bought them from ebay. Some were from user "Detroitcat" and some from user "funsport-usa".
     
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  19. Paul Schenck

    Paul Schenck Active Member

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    I thought some of the guys had mentioned a service mode that keeps the engine running??


    iPhone ?
     
  20. SFO

    SFO Senior Member

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    Not exactly service mode, but here is @Patrick Wong 's write up :
    To exit 'inspection mode', just turn off the vehicle like you would normally.
     
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