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Re: Data logger for P01 and P59
Posted: Wed Jul 08, 2020 3:56 pm
by antus
If your not aware there is an interesting ADX by forum member Jayme here for the AVT tool
viewtopic.php?f=10&t=2314#p22289
There are some ways to speed it up. Being that I dont have a VPW car I havnt used this tool, so I may be covering items that are already in the logger, but options inlude:
1) Priority of different PIDs, perhaps 3 levels. Something like coolant temp wont change fast, so you can log it less frequently and still have useful data logs. This frees up more time for PIDs where you do need the speed
2) DPID is a function where you can define and pull back 4 data items (i think) per request, which saves a lot of turn around time.
3) You can log at VPW 4x speeding the data bus up to 41.6k But to do this you need to silence chatter on the data bus and this will cause the dash to chime etc, and you may loose bcm functions which might include disabling a fan. There are also some pre-requisits to get the PCM to switch to 4x times mode, you cant do it while the engine is running and your logging, but I think you can switch and then start the engine.. though looking at Jaymes screen shot in the 3rd post the engine is not running while logging at 4x. Its messy but very fast speeds might be possible. If it cant do it out of the box maybe we could patch the OS to make it work. Worth it? Probably not.
Re: Data logger for P01 and P59
Posted: Wed Jul 08, 2020 3:58 pm
by NSFW
The 10.4kbps rate is a problem, but I still think we can get more parameters per second than we have now. Currently the logging process looks like:
1) the app configure the dynamic PIDs, which basically mean the app says "when I ask for 0xFE, send these six bytes."
2) the app asks for the dynamic PIDs
3) the PCM reponds with the bytes that were requested.
4) go to step 2.
I'm pretty sure it's possible for the app to ask the PCM to stream the PID values continuously, so step 4 would be "go to step 3." That is, the app wouldn't have to continously send the dynamic-PID requests. That would free up some data bus bandwidth. It probably wouldn't be a huge increase in data rate, but I think the difference would be noticeable. We're not just losing time due to bytes over the wire, we're losing time because every message (in either direction) is followed by a timeout period, and we'd be cutting the total time spent in timeout in half.
I tried to get that working in the beginning but the PCM would only stream data for 10-20 seconds or something like that. So I'm sure the functionality exists, I just wasn't doing it quite right.
A list of standard PIDs shared by all P01s and all P59s would be great. Someone just needs to step up and do it.
And yes, being able to log memory addresses is a huge help for reverse engineering. It's one thing to look at a memory location in IDA and say "I think this must be used for...." but if you can log that value and confirm that it does what you think, that's really useful. Or you find out that it doesn't behave like you expected. Or sometimes the reverse can be useful - watching something change in data logs can give you insight into what it is used for and how (or if) you should think about tuning it.
Re: Data logger for P01 and P59
Posted: Thu Jul 09, 2020 5:50 am
by bubba2533
NSFW wrote:
A list of standard PIDs shared by all P01s and all P59s would be great. Someone just needs to step up and do it.
How would one go about doing this? I am imagining you would need to request the list from each OS.
Re: Data logger for P01 and P59
Posted: Sat Aug 01, 2020 12:53 pm
by aaronc7
Hey guys, I'm not real smart on this stuff, but I am pretty persistent and trying to sift through and learn as I go.
Been trying to identify more PIDs for viewing/logging. In my case with an OBDLink and phone app, but I have found most of the resources around here/PCM hammer github, so here I am. And would seem to be directly applicable to the PCM Hammer logger program too.
Here's a few I have tested successfully today that I haven't seen advertised/posted yet. This is with a C5 Corvette and P59 -7603 OS. I was mainly digging trying to find the ethanol ones and any other "essentials". EGR one you could tweak the equation to log a wideband or fuel pressure sensor or whatever you wire to that pin.
Been thinking about throwing together an all encompassing PID list just to have as a reference. I probably don't have the knowledge or skill to go and figure out a bunch of the unknowns though.
Set OBD header to "Auto" or "6C 10 F1"
Name--------------------------PID--------Equation-----------------Units
Oil pressure------------------22115C-----A * 4.326 - 110.313----kPa
Ethanol Sensor Frequency---22139C----A-------------------------Hz
EGR V-------------------------22114B----A/51---------------------V
Ethanol Content--------------2212F3----A/2.55-------------------%
Fuel Temp--------------------22139D----A-40 (I think)------------*C
Knock Retard-----------------2211A6----A*0.088-----------------*
Re: Data logger for P01 and P59
Posted: Sun Aug 02, 2020 1:51 pm
by Stokes1114
That's pretty awesome you found those PIDs. I've been trying to get ethanol PID to work on my 12216125 (flex OS) for a while. The normal 52 returns some data, but none of the formulas work for me. I know my PCM has it, as I've seen it on some apps. Gonna give these a try tomorrow.
Re: Data logger for P01 and P59
Posted: Sun Aug 02, 2020 7:54 pm
by kur4o
aaronc7 wrote:Hey guys, I'm not real smart on this stuff, but I am pretty persistent and trying to sift through and learn as I go.
Been trying to identify more PIDs for viewing/logging. In my case with an OBDLink and phone app, but I have found most of the resources around here/PCM hammer github, so here I am. And would seem to be directly applicable to the PCM Hammer logger program too.
Here's a few I have tested successfully today that I haven't seen advertised/posted yet. This is with a C5 Corvette and P59 -7603 OS. I was mainly digging trying to find the ethanol ones and any other "essentials". EGR one you could tweak the equation to log a wideband or fuel pressure sensor or whatever you wire to that pin.
Been thinking about throwing together an all encompassing PID list just to have as a reference. I probably don't have the knowledge or skill to go and figure out a bunch of the unknowns though.
Set OBD header to "Auto" or "6C 10 F1"
Name--------------------------PID--------Equation-----------------Units
Oil pressure------------------22115C-----A * 4.326 - 110.313----kPa
Ethanol Sensor Frequency---22139C----A-------------------------Hz
EGR V-------------------------22114B----A/51---------------------V
Ethanol Content--------------2212F3----A/2.55-------------------%
Fuel Temp--------------------22139D----A-40 (I think)------------*C
Knock Retard-----------------2211A6----A*0.088-----------------*
There is some nice program that will get you a list of the supported pids of the OS, unfortunately it only have descriptions of the pids, we need to add conversion factor and units, and some other useful info if there is any.
I will be really glad if you join the project and be able to add all the missing info we have.
Here is the thread of the program.
https://pcmhacking.net/forums/viewt ... =42&t=6642
Re: Data logger for P01 and P59
Posted: Sun Aug 02, 2020 8:22 pm
by Gampy
kur4o,
It would be helpful to remove the '
www.' from that link ...
It currently comes up as "Your connection is not secure"!
And if I'm not overstepping, url markup works like,
Like so,
Code: Select all
[url=https://pcmhacking.net/forums/viewtopic.php?f=42&t=6642]Segment Swap utility[/url]
Results in,
Segment Swap utility
If I've offered up something you already know, my apologies.
-Enjoy
Re: Data logger for P01 and P59
Posted: Mon Aug 03, 2020 2:33 am
by aaronc7
kur4o wrote:There is some nice program that will get you a list of the supported pids of the OS, unfortunately it only have descriptions of the pids, we need to add conversion factor and units, and some other useful info if there is any.
I will be really glad if you join the project and be able to add all the missing info we have.
Here is the thread of the program.
https://pcmhacking.net/forums/viewt ... =42&t=6642
Alright, I paired down the PID list to what my car supports and I'll try to fill out what I can for ones that seem useful. I think maybe the only big things missing for logging is the VE/SD derived mass flow rate and/or g/cyl. Maybe "calculated engine load" can be related to g/cyl. Target equiv ratio / lambda would be nice too when you're dealing with flex fuel. I'll see if I can come up with anything useful.
Re: Data logger for P01 and P59
Posted: Wed Aug 05, 2020 3:47 am
by bubba2533
I think AFR/EQ ratio is given in the PID info NSFW got and put up on github.
Not sure of the equation/units, but 22119E should be the PID. 22FC12 is another PID that reads the same RAM address, but it's not modified whereas 22119E is converted from the raw RAM read.
I've found a handful of others, but it would be nice to have a place to collaborate on this. The cylinder airmass is proving to be quite difficult to find. I have found a ram address, but finding the PID is not as easy.
Re: Data logger for P01 and P59
Posted: Wed Aug 05, 2020 4:33 am
by aaronc7
119E is commanded AFR, but it's not a useful on a flex fuel vehicle because it is modified by the current fuel stoich value. So EQ ratio is much more convenient in general I find.
Perhaps FC12 is lambda/EQ?
I haven't looked at the code/logic itself, but with EFI live you have the ability to log cylinder airmass by PID or direct memory access. And it's always been advised to use the DMA when able as it supposedly takes all temp modifiers into account whereas the PID may not. Can't confirm any of that, but it may be one of those where it's preferred to log by DMA anyways.
That link above has a pretty extensive PID list, seems like a good of place as any to collab on PID stuff.