Data Logging, Combining 123+ data and AFR for tuning analysis Options

[Ishley]

Background: I rebuilt my ‘72 1.7 a few years back. I completely stripped the car back to bare metal… did a bunch of metal rust repairs… painted the car and eventually moved onto the engine. This Forum was a great resource as were some of the Youtube videos. For the engine rebuild, I basically kept the engine case and replaced everything else. All AA Performance…2056 with a webcam 73, 42X36 heads (no vents) and a 123 distributor… running DJET. The engine is actually a ‘73 replaced by some previous owner.

The DJET has also been completely rebuilt, MPS, throttle body and position sensor, new/old ECU (old one wouldn’t run the fuel pump), head temp sensor… wiring harness (Injector and Engine), 2.0 injectors along with about everything you can think of. I also have a Bursch exhaust. The car runs really good… and with the exception of a few failed parts, it’s perfect. I’ve put about 4K miles on it over the last 2 years.

Science Project: During the tuning process I discovered that the 123 + with bluetooth builds a log file every time you connect with your phone. I’m pretty sure this is the only 123 version that does that. The file resides in the File area of your phone (makes sense) and is a pretty rich set of data parameters. It's easy to dump the file into a spreadsheet.

I also installed an AFR gauge and a bung for a Wideband O2 sensor… and noticed that it had the ability to also log AFR readings. This got me thinking… Joining the two data sets together would be a great tool/ resource to help with the tuning of the car. So this past week I spent some time trying to get the AFR to communicate with the Windows laptop. I ended up upgrading/buying a real AEM gauge (mine was a Chinese knockoff) and some cables… and was finally able to collect data. I use Realterm software (free) and it can add a timestamp to each data point.

Next problem…. The AFR puts out about ten times the number of data points then the 123 distributor does. Also…Realterm date stamping is very limited compared to the AFR gauge. I haven't quite figured out how to marry the data completely together yet. I’m doing this in Google sheets… and find it slow and clumsy compared to using Excel (which I don’t have any longer). But I was able to chart the data sets individually and stack the charts on top of each other which got me most of the way there.

This was a cold engine (135F) and a quick drive( 3 Minutes) in suburbia …. And is just meant to show what is possible.

I also sent an email over to the 123 guys in Europe asking if they have ever considered building a tool and system like this (they said they are always evaluating ideas) There are now Blue Tooth enabled O2 Kits which could be a nice pair with a 123+ reporting tool. The idea works for FI or Carbs (and other cars)… as long as you have a 123+ and an O2 sensor/gauge that can log data.


Thoughts??

[Ishley]

The Bluetooth log from the 123 is collected on your phone. I don’t know of any other way to get the data. I used the serial connection from the AEM AFR gauge which a 2 wire connection TD and GRND. The afr just streams everything that the gauge sees… which is quite a bit of data. Most AFR gauges have a +5v wire which can be integrated into a modern ECU… but that’s not what a 914 has unless you are running MegaSquirt or Haltech.

The 123+ data log has the following data;

TimeStamp;CurveNr;RPM;Advance;Vacuum;Temperature;CoilCurrent;Voltage;ShiftLightA
ctive;GPSms;raw

There is an extra field which is always -30. I assume it is the max vacuum range. The temp aligns well with oil temp. I don’t use vacuum on my 123+ but I have it connected and I get the data. It’s a good indicator for throttle position. So with this data I can really see what happens when I accelerate, cruise, gain speed, my advance etc. I linked it with the AfFR data so I can see if my tune is in line with what I want. I really don’t want to go lean for extended periods.

The AFR data is just;
Timestamp, AFR

I find just watching the AFR gauge flash numbers helpful… but this datasets really helps confirm where my tune is and where I might want to make adjustments.

I’m running a non-stock engine with a mix of injection parts,
Cam etc. There is no book on what to do… just trial and error.

This same setup is useful for DJET and carb tuning.