How to-data log air fuel (and read it) using the Predator.

[DolSVT00]

Disclaimer: this is not meant to replace a wideband, it is a make shift tool to help you get close and troubleshoot problems.

First you need the Diablo sport Predator and a spot with traction to make a full pull or at least a low rpm 2nd gear pull and a full 3rd gear pull.

Second you need to data log. Using the predator go to troubleshooting, real time data, advanced WOT (you must have the updated predator firmware) now click choose from list. Now select (it will add an asterisk) your Short term fuel trims (both of them) and your Long term fuel trims (both of them). You also need to select your timing, Maf voltage, rpm, gear commanded, throttle position voltage, and load.
You may want to select other data and thats fine, just know that the predator only stores so much and if you pick too many it will mess up the log and it will not play back. Ok now select fast rate and answer yes to log the data, now begin your pull. Make sure to press ESC after completing the pull, keep the log short and simple to avoid confusion.

Third you need the power plug and serial cable to plug your predator into your PC, this stuff is available at radio shack, make sure you have a serial port that will work on your PC; otherwise you will need a serial to USB converter (also available at radio shack). You will need this software installed on your PC, CMR Dat 200 (for acquiring logs from your predator) and you will need Dataviewer 3.1 (for viewing logs). Ok now upload your log using the upload log function on the predator and the CMR

Now name the log and save it to your desktop. Once saved, close the CMR DAT program and open the Dataviewer and open the log.



Now select default ford.


Now select Dyno guage and zoom in



Pick these PIDÔÇÖs (the ones with the green check)


Now youÔÇÖre ready to look at the data for any given RPM use the slider to move forward and backward through the log data (you can check the gear commanded box to see what gear your data is from) (see below for slider)



Now letÔÇÖs take a look at the data.



As you can see, IÔÇÖm in 2nd gear at 5200 rpm; my lambda is 0.7813 on banks one and two (bank 1 passenger side, bank 2 driver side) you have to do the math, 0.7813 X 14.7 = 11.485xx (Multiplied) this tells me I have an air fuel ratio of approximately 11.5 at 5200 rpm in second gear.
Note: 14.7 is Stoichiometric for most fuel, depending on what fuel or what additives are in the fuel that value could change. For example if you have 93 octane with 10% ethanol the Stoichiometric value could be as low as 14.1 instead of 14.7 as used above. (I use 14.7 as a starting point it will get you close for this type of log)

Ok letÔÇÖs do it again


As you can see, IÔÇÖve just shifted into 3rd gear at 3869 rpm; my lambda is 0.7772 on banks one and two (bank 1 passenger side, bank 2 driver side) you have to do the math, 0.7772 X 14.7 = 11.348xx (Multiplied) this tells me I have an air fuel ratio of approximately 11.3 at 3869 rpm in third gear.

Pretty simple huh? IÔÇÖd like to add, if you retard (remove) timing in your tune it will add safety factor to obtaining your log, especially if your air fuel is all screwed up and youÔÇÖre trying to nail it down (Basically on the Predator, go to performance tune, pick your tune, go to modify parameters, go to spark advance, go to global timing adder, subtract about 4 points for starters).

If you need to add more fuel or subtract more fuel in your tune (once you have viewed your log) you can go to performance tune, pick your tune, go to modify parameters, go to WOT fuel and add points to the rich side on the 1k to 3k rpm range or the 3k to 6k rpm range (depending on where you need it according to your log). You can also subtract fuel if you need to.

There are many more things you can do to adjust your fuel and timing curves such as MAF transfer and spark advance but thats stuff for another how to