Data is described in SAE J1979, which is not available on the internet.
Most of the data (pids) are described here: http://en.wikipedia.org/wiki/OBD-II_PIDs
This applies to vehicles produced until 2006. In 2007 more than 50 new pids were defined which may have some information needed for this problem, but that information is not publicly available, and only used in 2007 and newer vehicles.
With the available pids there will be problems. Pid 10 (Maf airflow) is insufficient. Maximum is 655 grams/second and big diesels may use more air than that.
Injection duration is not present within the 2002 specification.
Fuel temperature is also not present within this spec.
You tell me how it should be done. I don't think it's possible for a diesel, which is what I have been saying all along.