How do I determine the Direct Injection pump lobe offset?

For DI pumps that run off the camshaft, as described, the angle in crankshaft degrees from the tip of the pump lobe to the pattern lock position for that camshaft.

The pump offset is the angle in crank degrees from the TDC of the pump before the camshaft index point, to the camshaft index point. The camshaft index point is the tooth edge used in the camshaft position offset calculation. 

This tooth may vary with the exact reference mode in use.

In the diagram above we see the Reference (Crank) signal, the cam signal from a Bosch 40/140 type cam trigger, the cylinder 1 ignition coil voltage, and the DI pump lobe lift, with Cylinder 1 TDC angle as the X axis. Note – this plot reflects the lift vs. cylinder 1 TDC table detailed above.

The Reference pattern lock position is the first falling tooth edge after the missing teeth, which in this case gives a Reference Offset of about +45 degrees.

The Camshaft Pattern Lock position is the falling edge between the 40 degree segments of the signal. In this case a Camshaft Position Offset of about 120 degrees is shown ( note that this is the angle from the Reference Lock position, NOT the Cyl 1 TDC position).

A typical ignition coil signal is shown at about 28 degrees BTDC.

Finally the DI Pump Output Offset is shown, in this about 85 degrees, ie the TDC of the pump lobe is 85 degrees before the camshaft pattern lock position.

Note – as the camshaft position moves in a variable cam timing engine, the critical point is that the DI pump lobe TDC position is always (in this case) 85 degrees before the camshaft pattern lock position, even when the camshaft pattern lock position has moved relative to the reference position.

In the reference mode help, modes that are commonly used in DI applications have the camshaft pattern lock position defined.

Technically any lobes offset can be used, but common practice is to measure from the camshaft lock position to the nearest lobe.