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Cheap Catalytic Convertor getting P0420 same gas mileage

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by WBLY, Apr 22, 2022.

  1. drone13

    drone13 Active Member

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    1st suggestion: Pony up the $5 for the pro version so you don't have to deal with the lite version limitations. You will probably want to get the PID pack for Toyota so you don't have to try and program in the PID addresses and calcs yourself. For the purpose of strictly OBDII data which you are collecting for this issue the PID pack is really not needed since everything we currently need to log is generic OBDII, but it will always be handy for other proprietary systems like HV system, ABS, Trans, inverter, and many other systems not covered by generic OBDII PIDs.

    2) Get rid of all GPS data from your logging. It's cool I guess to be able to map where you drove with Google Maps, but you are collecting a lot of data that is useless to the problem we are collecting data for and each data point you are logging counts toward your maximum data capture rate of whatever BT adapter you use. It is easy to introduce aliasing to the key fast moving data like O2 sensors making the data worthless for analyzing. Limit the data collection to only the data discussed in previous messages in the thread. You had a number of drop outs in your data, this might be a result of trying to collect too much data at once and the BT adapter couldn't deal with saving all the data in the small buffer fast enough. BTW, did you notice the OBDII vehicle speed is MPH (the one we will use) and the GPS vehicle speed is meters/sec? Get rid of GPS data, we don't need it. All we need is generic OBDII data for this.

    3) STFT was an optional data collection item. LTFT is not optional and it wasn't collected. LTFT is important so we can either see the ICE is running within parameters or not. If you have engine problems that needs to be determined and STFT is not good for that since it is just a fine tune adjustment of the LTFT either additive or subtractive to LTFT. While I could guess by the STFT numbers the LTFT is likely alright, we really need to see this. If the engine is running out of spec we would need to fix that before anything else... so it's important.

    4) There is no O2 data. Kind of the whole point of this data collection. It needs to be there or we got nothing.

    5)Might as well change the coolant from C to F. Since you are reading MPH instead of KPH, might as well switch that over. You could calculate this in Excel using another column, but just capture in F is easier unless you really like Celsius. Coolant data isn't absolutely required, but if doing a cold start test it's nice to see when the catalytic reaction starts. Cheap cats or degraded cats might not start the catalytic reaction when a good OEM would. This means monitoring might fail if the ECM expects the catalyst to be working when it's not ready yet.

    6) Whatever else you do, make sure you are not capturing data by Frame or Synchronous. This won't capture useful data for fast sensor logging. This not a big deal for slow sensors, but is critical for things like O2 sensors.

    Don't get discouraged, this is your first attempt and it will get better from here. Take the above as just a bit of training and let's get this right. Attached I have reduced your data collection to just the things that make sense to capture and as you can see there isn't even enough data to try to graph to make some sense of this, no LTFT and O2 sensor data. BTW, I know I mentioned this before, but I really prefer OBD Fusion for data collection. Might just be me, but I had a ton of problems trying to get useful data from Torque Pro with dropouts and difficulty getting it setup for meaningful data capture. You might want to try that. Whatever you do, get the paid version or either app and don't expect to get the best results from a freebie app. OBD Fusion is $10 I believe and there are versions for both Android and IOS.
     

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  2. WBLY

    WBLY New Member

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    Thanks. I don't know why the GPS date was there and why the 02 Sensors data was all dashes. It's $5 for T-Pro or Fusion from the google play store. So I went with the later. I will play with it today and try and use it on my driver tomorrow to collect real data.
     
  3. WBLY

    WBLY New Member

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    Is this ok? It was done with OBD Fusion, 8 seconds while parked.

    I can pay another $15 for more features fory 2006 Prius. See the attached screenshot.

    I was also concerned that I wouldn't get the O2 data per the other screen shot. However it seems to be there.

    Can I filter out this code so that it doesn't set the check engine light? I saw something in OBD Fusion the implied I could screen it out.
     

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  4. WBLY

    WBLY New Member

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    How is this data? Fusion stopped logging for awhile and I don't know why. So I deleted the STFT and in the meantime I found how to set the sampling 2 a half a second. I also deleted the three other logs. Logging worked after that. I did NOT get a P0420 check engine light event during this run.
     

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  5. drone13

    drone13 Active Member

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    On the log file 162100 it is very close, just a couple of changes. The sample rate is way too high. It looks like 50ms (20 per sec) Please change to 500ms (twice per sec). No need to sample that fast. I never thought I would say this... but too much data!!

    Get rid of Bank 3 data. The Prius only has Bank 1 so that's all you need. You have that on both LTFT and STFT Bank 3 as well as Bank 1 data. We do need the Bank 1 data. Bank 3 data (all 0s) can be stripped out with Excel, but better not to have that in the data collection list.

    No need for O2B1S1V and Lambda. You can pick whatever one you like. I like raw V data, so I generally just use O2B1S1V. Lambda is fine, but that is a calculated value and not raw data. But whichever one you prefer is OK. I just don't see a need for both. O2B1S1V data of 3.33 is equal to Lambda 1.0, so either gets the point across.

    Other than that, the data collection looked OK but it is very small sample with no driving and the coolant temp was too low to be useful for analysis.

    With the above couple of changes you're ready to do some drive testing that we can evaluate. I have attached your data formatted for graphing and with extraneous data removed as an example. You can order the columns any way you want, I generally choose this order to quickly see relationships between data, but there are no real rules for this. Just whatever you like.
     

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  6. WBLY

    WBLY New Member

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    I think the last log I put up has what you want. However, the error didn't occur then. Of course, it did the next time I drove my Prius (& I wasn't logging the data). I can smell it when it's going to get an error when the windows are open. Log file 123444 that is.
     
  7. WBLY

    WBLY New Member

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    Here's two recent files that should be to your spec. There were no errors during these.
     

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  8. WBLY

    WBLY New Member

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    Here's one that the P0420 check engine occurred near the end. I shut off the logging when I noticed the code though it probably wasn't immediately after the code but within 5 minutes for sure. I don't see anything unusual, but I don't have any experience with this type of data.
     

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  9. WBLY

    WBLY New Member

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    Anybody out there that can tell me what the last data I collected shows?
     
  10. WBLY

    WBLY New Member

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    So for some reason to get the O2 voltage for Bank 1 Sensor 1 & 2, I have to use these values in OBD Fusion. O2 sensor voltage WIDE range O2 voltage (Bank 1 Sensor 1) (V) AND O2 voltage (Bank 1 Sensor 2) (V); otherwise Bank 1 is always zero. There was no check engine P0420, error during this run. From what I can tell O2 voltage (Bank 1 Sensor 1) (V) is around 0.64-0.7V AND O2 voltage (Bank 1 Sensor 2) (V), is around 3.3V, except for decelerating and stopping/starting.
     

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  11. WBLY

    WBLY New Member

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    Here is a short drive where I got the check engine/P0420 error toward the end. It was the exact trip/drive as the last error. I took my Prius to a mountain bike trail about 20 minutes from my house and went for a hour'ish ride. Then I drove home but stopped at a store where the error again occured. The drive is 30 MPH, mile out of the park with two stop signs. Then a couple mile 55 MPH road to a round about, The check engine occurred somewhere in the next leg/end of the trip including the roundabout ....... Then about 1/2 mile to a left turn and another 1/2 mile to a right then immediate left turn into the parking lot. The check engine was on for sure by this time. I'm thinking the error is because of line 377 where is hesitated in accelerating (i.e. steady speed) and the O2 voltage (Bank 1 Sensor 2) (V) was 0.115V.

    Does anyone know how to include check engine lights in the data from OBD fusion?

    Two does anyone know how to filter out P0420 codes from causing a check engine light?
     

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  12. WBLY

    WBLY New Member

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    I bought a used O2 sensor off ebay that was genuine. I still had the same problem. The seller gave me a tip to put a fouler in and that's been working for 3 weeks. So cheap O2 sensors are fine. Cheap Caty's no, but can be worked around since $145 was much cheaper than $2500. Sure, I'm polluting more but the real problem is someone stole it in the first place. Spend your focus on solving that problem first.

    I used a right angle fouler instead of the double straight spark fouler. The right angle brass one was $3 off ebay a couple years ago but all I could find was a $38 one on amazon. Talk about gouging. I found a $9 one off aliexpress including shipping and it got here in 2.5 weeks.
     
  13. PriusCamper

    PriusCamper Senior Member

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    Got a link to the cat you bought? Would be good to know the cheap ones that don't work, because most of 'em work without issue.
     
  14. WBLY

    WBLY New Member

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    No link as they don't sell it on amazon anymore. There was a lot of them on amazon at the time and it would have been nice to know which ones work before hand. This is all they have:

    [​IMG] PriusCat1.jpg
    Order detailsOrdered on March 15, 2021 (2 items)
    MAYASAF Catalytic Converter Fit for Toyota Prius 1.5L L4 2004 05 06 07 08 09, Quality High Flow Converter (EPA Compliant)
    MAYASAF