As there's only five parameters in each log, and each log apparently covers a different time period, it's not possible to relate a parameter in one log with another that's in a different log. When I listed the desired parameters, it was with the hope the your device can log more than just five. Have you looked at the P0420 Diagnosis thread? P0420 Diagnosis. It can provide insights into what to look for and record. This code does not have easy answers, as is evident from it's length -- almost 2000 posts.Attached are .txt files for some extended logging with BlueDriver during a long trip under freeway conditions at speed. Since BD says its best not to try to log more than 5 variables at a time, I selected groups of the variables
That's a test of the sensor response. A bad sensor could cause the P0420 even if the cat is good. Where there's separate cats in each side, as in your case, the logs have to include the sensor and throtlle position data for both sides. So, both Equivalence Ratios, Both Oxygen Sensor Voltage, and the Absolute Throttle Position. That said, I'm not sure how reliable the result would be in this case, as well as in the other four logs. That's because in the previous logs, each line of data was 0.5 second apart. That could skew the results by introducing a delay in the data where in fact the changes are much closer together. But again, it could be tried.ving at steady freeway speeds and then lift off the accelerator and let the car coast slower for a bit,
There's electronic version that will mimic a good oxygen sensor waveform. I used them a few times on performance cars the had no cats. It's been while but I'm sure they are still around.The extension might work, if I could only reach the downstream O2 sensor and easily remove it, attach the extension and re-install with sufficient clearance. I'm not able to do that and reluctant to ask a garage to do it. I ran some more BlueDriver logging on Friday and they are attached below. The time intervals are about 1/2 a second. Is that too much of a time interval to make the data useful? Any further interpretations? Thanks. LRV
It's been my understanding that when a fuel cut is initiated while the car is cruising (which is apparent in the graphs), the pre-cat A/F sensor signal (Lambda) should usually reach full lean (1.4) very slightly before the Rear O2 sensor reaches zero. If the A/F sensor signal reaches full lean well after the Rear O2, the A/F sensor might be defective. However, I've never seen reference to both changing at the same time meaning the cats are bad.I was told that both front cats are bad and that such is shown by the lack of a delay in the graph on the O2 sensor immediately behind the front cats responding to a change in the upstream MAF sensor, on both sides.
If you do want to put new cats in, the cheapest route would be either have an exhaust shop weld some new ones in, or get a walker replacement exhaust assembly. Dealer cats are expensive. A cut would probably run $60-$150 at a exhaust shop, and another $60-$100 to weld one in. At least this is prices around my area.Thanks Plain OM. Any chance that cardoc is still around? I'd love to get his input on this. The dealer says the two bank 1 and 2 upstream cats are bad, but that the third downstream cat is OK (at least for now). The dealer quotes $5724.26 total price to replace the two upstream cats! Does not include replacing any of the 5 O2 sensors. Outrageous. I'll do some looking around for comparison quotes. But it raises the question of what to do. If the cats are bad, and it won't pass smog, I can't sell it "as is" to anyone except to the State of CA who apparently will give me (and anyone else who wants to get rid of an old car) $1000. That would mean having to buy a new car. This 2005 model has had its problems, but it works well for me as my travel and fishing vehicle. The Gen 4 and 5 Outbacks are bigger and so not as attractive for my size and uses. And, they cost a lot more money. So, perhaps I'll look at another Gen 3 but a '06 - '09 model. But before deciding what to do, I would love to have someone who can really decipher the BlueDriver data I've posted above in several posts and contrast it to the dealer generated data posted immediately above which supposedly shows for certain that the two cats are bad. One last plea for help. Thanks. LRV