What do you guys think about making a tutorial thread on how to do this? Perhaps we as a group can refine it and eventually make it a sticky? I've read a bunch of posts and finally today recorded my first set of data on the drive to work. I'm using a Veepeak ELM from Amazon, $12, and the Torque app for Android.

In the torque app, which I'm still learning, you need to select what data you want to record. As this was my first time I selected a bunch of stuff. What should we select?

Once at work I connected my phone to my computer and opened the file. You access the file by opening your phones folder and looking for torque data. The data is in the form of a .CSV file. Excel or similar program can open it.

Upon opening the data I had to make the columns wider so you could actually read the headers. Then I made a first pass at organizing the data. However this is where some input is required from you guys. I decided to freeze the header row so as you scrolled down you can see what data you are looking at. I then decided to make the first column RPM's and freeze it as well. I didn't have the correct TPS box checked for this run but I think I'll have it right on the way home. I was thinking about TPS next? I'm attaching my modified file for the smart people to look at and make suggestions for a final layout.

Then comes interpreting the data? In my case this is data from my 1996 XJR that's been in my shop for 2 years and I just got it out and drove it home for the first time yesterday. I've documented most of the work performed in other posts. For the purposes of this thread I will say from driving it, not looking at data, it idles rough but seems to be running fine at all RPM's above idle. Looking down at my phone while stopped it seemed like the stft were high or pegged at max. Would that mean super rich and cause the rough idle?

The data started recording about a minute after startup.

My uneducated review of this data:
1. No data from some of the boxes I checked in the torque app. Probably no such sensor on our cars.
2. Ambient air temp data is screwed. Do we even have such a sensor?
3. Intake air temp seemed about 10 degrees high at startup.
4. Mass air flow data seems screwed. Which of those columns is important or both?
5. Charge air cooler temp seems off as well. Do we even have that sensor?
6. Engine oil temp seems screwed.

Can you guys make recommendations on what data we should be logging, and how to format the spreadsheet? Also, how long should we record the data for on average? I think my drive was about 25 min today. Then, as a tutorial as well as a help to me, how would you interpret this data? What would be a "normal" range of numbers for the corresponding data?

 

With the Bluetooth OBDII dongle (GO point) I have, and the Dash Command app… I can record data logs while driving and then send the log file via email where I pull it up on my laptop with Scan XL. Palmer Performance created both Dash Command and Scan XL I believe. It is a bit cumbersome, and this is the only Windows laptop I have (running windows 7)…. But it does work…

 

Everyone's going to have something different. There is no Torque app for iPhones. I use OBD Fusion with my iPhone and WiFi ELM dongle.

 

When I used the live data before my authorization key vanished ( 25 uses ) there was quite a learning curve and unfortunately everyone is using a different software vendors as was I ( but I liked mine as nice graphics )

TourqePro seems to be a common this website use by reading others

From what I came up for PIDs

Short Term Fuel Trim / Bank 1 and 2

RPMs

Mass Air Flow Rate or Throttle Position Sensor ( in % of full open , 13 % is full closed on the X300 )

Engine Coolant Temp

On the end of your opening post I will give my take on your observations

# 4 / engineering rule of thumb , for every liter of displacement at 650 RPMs you should have 1 gram per second mass air flow

so 4. 0 liters at the higher RPM around 4.3 grams per second ( higher for the SC engine as you have " some " compression at idle )

So your wide open throttle ranges around 175 for normally aspirated and 225 for supercharged ( factory , not modified )

There is sometimes a software error on the ELM - 327 devices that you must multiply by a factor of 10 or 100 to be correct on the MAF

# 2 / You have 3 different air temp sensors , one for the climate control only , one for the windshield washer heated jets only , ond one as the engine intake air sensor only

# 6 / I beleive there is a TSB on the oil temp sensor upgrade

More later as I add to this post