no_6_oh_no

The CP-3 has 3 pistons to pressurize the rail and it runs at half the crank speed. When a cylinder is at TDC and firing the pump needs to be hitting TDC with one of the pistons or you get a rattle due to gear drive noise from the compression in both places causing the gears to kick.

To phase the pump break the lock nut on the pump loose and rotate the engine 20-30 degrees then tighten the bolt and check for noise. Repeat as neede duntil the noise changes or disappears.

It should take only to phasing attempts to make a difference. If it doesn't you may have another problem.

Diesel87

If the the pump is not out of phase and I try this, would it make my problem worse?

Diesel87

This may be a stupid question, but if I am looking at the truck, would I turn it clockwise or counterclockwise?

no_6_oh_no

Doesn't make a difference which wat you turn it. The idea is to change the phasing and that will happen either way. The easy way is loosen the pump and use the alternator to turn the engine backwards.

If it is phase and you get it out of phase, yes the noise will get worse, but, then you will know how to fix that.

Diesel87

Thanks man I'll try it!