Below is a short tutorial on logging data using Torque. This would be if you want to log B1S1, B2S1, and B1S2 O2 sensors to try to catch them doing something at the time when the PO420 sets. You could throw in MPH and RPM to the data log so you can figure out what the vehicle was doing at any given time. You could also throw in both LTFT and STFT for each of the two injector banks to tell if the system it is trying to compensate for a lean condition.. This will give you a large spreadsheet of data which you can pull into Excel and plot. If you don't know how to plot data in Excel, just post the Torque spreadsheet and I'll plot it for you. If you're running rich or lean, you can see all about it in the fuel trim and O2 sensor readings. But remember that the more things you monitor, the less frequently you get data points. Monitoring 9 pids at 30 scans/sec would update each one about 3 times/sec. Can make the tach and other plots look a bit jerky. Just keep that in mind as those O2 sensors cycle pretty rapidly and so do fuel trims. You can actually miss part of the cycles.

Launch Torque App in your device
Hit Gear Icon to go into Settings
Go into Data Logging & Upload
Go into Select what to log (in here you will select what PID's from the list you will log).
Select PID's from list (For this example, I will be logging Engine RPM, AC High Side Pressure, and MAF Rate)
Go back to Data Logging & Upload Menu and leave whatever options are there by default
Go back to main Torque App screen and select Realtime Information and select Start Logging (this assumes you are already connected to the ECU)
Do your drive test and/or let some time go by so that the logging takes place
Go back to main Torque App screen and select Realtime Information and select Stop Logging. You will get a message that the log file is being stored in your device.
Now in same menu select Email Logs
Select CSV
Select Save to Drive
Go into your PC, Log in to your Google Drive, and select & download the log File to your PC
Open the File in the spreadsheet program of your choice.
Massage the data to plot what you want to see.
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If you are talking about the add propane test, just plot B1S1, B2S1, and B1S2 O2 sensors in Torque. You can plot them and use screen capture, or alternatively use the logging feature to record what happens. I plan to give mine a shot of propane in the intake tube from a torch that I have (at idle) and look at the delay time the shot of propane takes between the pre-cat and post-cat O2 sensors. The torch I have is one of those 8" tall bottles with a self-lighting torch on the top that I bought at the hardware store. If my post-cat O2 sensor is already rich, I'll pull off a good size vacuum hose and check response time between sensors this way. Then you can compare how your converter respond and compare to one that isn't setting a Po420. At least that's the plan. I'll do what I can to help.

The Evap system test not being ready is just that - it hasn't run the test. Fuel level and temp outside has to be within a certain range for that test to complete.

Secondary Air always seem to be the last test to complete, and failure to run has been previously attributed (more than once) to thermostat not getting engine hot enough to run the rest.

 

Thank you, hopefully I can do some testing on Saturday.

 

I've thought about this a bit and please see comments/edit on post#29. Having the post-cat sensor maxed out may invalidate my example of a good cat. Maybe watching the post cat sensor's change in response to changed mixture input into the cat is a better way.

Here I pulled the fitting out of the brake booster but held it close enough to the booster port that it would still idle. In other words I created a big vacuum leak and watched all the O2 sensors go to lean. Then I plugged the fitting back in and took a screen capture of the resulting responses. Note that at idle there was about a 2 second delay before the post-cat sensor responded to the richened fuel mix. From the code description as I understand it, this is the kind of testing the PCM actually does. If the time difference is too short, then it sets a P420. this could also be done with the logging function, but results in a table of values.

 

You know, I tried the simple things first, changed the plugs and wires, holy cow were they bad, and, no more P0420.
A little embarrassed at how bad they got, but in my defense, it's only been six months.

 

Glad to hear things are now fixed. I take it that you made it through the smog check?

 

not quite yet, still waiting for the cat to clear the check, but everything else is good and no codes, so......

 

good luck!

 

Thanks, cat cleared on the way home, stopped by jiffy lube, good to go.
Can't believe the plugs would make P0420 continue to pop, but it's good now. thanks for all the help.

 

What kind of plug wires were those? I used AC Delco and only have problems when my headers would burn them. Had to really work on the routing and used many zip ties to fix.

 

Those were actually summit racing wires, but I don't think it was the wires, the boot tore while changing them; more the fact that I spend a lot of time off-road and my inner fenders are non-existent so, everything is constantly getting muddy and wet