Is it called the QSB-110C on the data plate? CPL8653?
I have one and I am no good at troubleshooting the VP system on it.
I can fire a commonrail on the ground, but the VP on this has made me scratch my head and walk away many times.
That particular version uses an ECM that reads cam signal only, much like the single sensor 2001-2002 Dodge
VP44 system does, but the ECM has 2 wiring plugs, which makes tracing circuits more difficult.
Try Quickserve, if you can read schematics, it'll certainly help you out.
Mark.