OBD logging and real-time histogram

[woody80z28]

Looking like this will work via OBDlink in TunerPro. It connects on my bench, will try it in the truck tomorrow.

Anyone know how to add EGR position to the datastream? That's where I'm wiring in my wideband 0-5v.

According to a post from 2009 I found it's PID.2811
https://ls1tech.com/forums/pcm-diagn...l#post11938549

[woody80z28]

It works! I had to build some lookup tables to convert C to F and KPH to MPH, etc...but it works. LTFT was showing 128 like obd1 so I converted that to 100 to show percent. Overall I'm happy with it.

"VN5000" is the original author of the ADX according to the header. I searched and didn't find any info on that name.

I attached an ADX capture to show the code for the PID. That's way over my head. Anyone have an idea how to code for PID.2811 to get EGR voltage in the datastream so I can do the wideband conversion?

[woody80z28]

Found a hex converter online and the byte string for KPH translates to M01P0D501R1. Did I mention that part is over my head? Haha

[woody80z28]

Ok I found this thread and it was very helpful:
http://www.gearhead-efi.com/Fuel-Inj...-OBDII-plug-in

Wiki also shows the PID info here:
https://en.wikipedia.org/wiki/OBD-II_PIDs

So, we know vehicle speed is:
0x4D 0x30 0x31 0x50 0x30 0x44 0x53 0x30 0x31 0x52 0x31 =
M01P0DS01R1=
'M' + HH + 'P' + HH + 'S' + HH + 'R' + H
Where 'M' is for Mode, "HH" is two hex ASCII bytes (e.g. 'F' 'F' for 0xFF). 'P' is for PID, 'S' is for size of PID data reply, and 'R' is for reply count. Note that the 'R' data is a single hex digit (e.g. '2').
= Mode 1 PID 13, get only 1st reply

So for PID 2811 I'm thinking: M01PAFBS01R1 (hopefully 3 hex bytes is not a problem and it still figures the delineation via the S after it for the size packet)
0x4D 0x30 0x31 0x50 0x41 0x46 0x42 0x53 0x30 0x31 0x52 0x31

[woody80z28]

Ok, it looks like that's working perfect! Won't know for sure until my wideband comes in this weekend, but I set it up just to read volts for now, and I get 0v cold, and then about 0.5-2.1v while driving, which is definitely influenced by throttle.

I also tried to log PID 68 commanded EQ ratio (hex 44), but can't get it right.
0x4D 0x30 0x31 0x50 0x34 0x34 0x53 0x30 0x32 0x52 0x31
It sends back 2 data bytes, and I set it to 16bit in the ADX, but there are two equations online and neither get the output to about 1 in closed loop.
2/65536(256A+B) and ((A*256)+B)/32768
The latter is closer, but not there. I'm not sure it's an equation issue though. Cause the data has spikes in it that wouldn't make sense for EQ ratio. I set it up identical to the way MAF and RPM are done (which are also 2 data byte PIDs.)

[kur4o]

The afr pid is 119e and is 1 byte long. Conversions is x*10. Let me know if you need some other info for logging. You are the perfect guinea pig for the adx improvement.
It is good to know that not all PCM supports all PIDS. If you get weird data or no response it might be because the OS doesn`t support it.

Do you have a copy of the adx used.

[woody80z28]

I do have a copy of the ADX I started with and the modification I'm at now. I'll post them tonight.

I just searched pid.199e and pid.119 without any hits. Just add all four characters in hex to the string? And that comes back as commanded AFR?