I know on common rail trucks the injector controls the timing and all the cp3 does is pump fuel. This is probably a stupid question, but does it matter that I turned the motor over while having the CP3 off the engine? I had the pump off when I was installing my new valve springs, and wasn't completely sure about starting the truck without knowing for sure. Thanks.

 

no the cp3 shaft is not keyed or anything like that it`s just a tapered shaft put it on and start it up

 

Good. I have already put the cp3 back on, just wanted to make sure i wasn't going to hurt anything. Thanks.

 

Won't hurt anything at all. If you get a hard to find rattle that sounds like timing knock you may have to phase the pump to the engine.

 

Ditto!!!!!

 

Could someone explain pump phasing?

 

The CP3 has a compression cycle that compresses the fuel for the rail pressure, same as the engine has a compression cycle that compresses the air. When these 2 are out of synch it can cause noise in the CP3 gear drive form the lash slapping on out of synch compression cycles.

Its commonly called timing the pump but its really phasing the compression cycles between pump and engine so they coincide.

 

Thanks for sharing the knowledge.