FUEL INJECTION PUMP TIMING
With the Bosch injection pump, there are no mechanical adjustments needed or necessary to accomplish fuel injection
timing. All timing and fuel adjustments are electrically made by the engine mounted Engine Control Module
(ECM).

 

Not true and play in the pump is entirely different. The gear knock never comes back if thats what it is.

If you have play in the pump the pump is junk and all the timing in the world will not help it. The slack in the gears is what is being addressed.

 

their is to many different Variables of what is really trying to accomplish buy doing this. If anyone thinks they are trying to time the CP3 pump they are dead wrong. I was thinking that the only possible reason for doing this is taking out the free play??????? Free Play where in the pump or in the gear housing?
I was thinking in the cp3 pump???? correct me if i am wrong
If in the gear housing, you have more problems then being able to adjust it by moving the cp3 pump that isn't going to fix anything.

 

Read post #9 for the why and what.

There is ALWAYS gear lash on any gear drive system, its design criteria. In the case of the CP-3 it is doubled because the crank gear drives the cam gear which drives the IP gear. The IP is a rotary pump with very very close tolerances, if you have slack in the IP the truck ain't running. The only variables are the gear lash between gears.

Its normal to phase or time 2 high pressure pumps that are gear connected. By design the CP-3 is driven at exactly 1/2 crank speed and the compression strokes of the CP-3 coincide with the compression strokes of the engine. The timing is done to satisfy the NVH initiatives and quiet down the engine.

You can't move the pump because it is solid mounted, but you can move the gear on the pump so the compression strokes coincide with each other. In a strict sense it is timing the pump to the engine, not for fuel delivery but rather to minimize the amoutn noise inherently generated by gear drive systems.

Functionally there is no gain by timing the IP to the engine, for NVH and expected life there is reasons for doing this. Every time the out of synch cycles cause gear slap it sends high frequncy vibrations thru all the connected pieces. This will eventually lead to metal fatigue, acclerated wear, and possible early failure of any number of pieces in the engine assembly.

 

light bulb just went on. Understand that now, what is trying to be accomplished
The timing is done to satisfy the NVH initiatives and quiet down the engine.

Read more: https://www.dieselbombers.com/newrep...#ixzz0Xq21Gvqu

 

OK. If you were timing the pump to correspond with one of the 3 internal pistons int the CP3 to match the TDC of a firing cylinder, then the CP3 would need to rotate at the same rpm as the crank. IE 3 TDC events per revolution. 2 revolutions 6 TDC events. However, this does not make any sense to me as the CP3's in the Cummins is the same as the CP3 in a Duramax. 6 cyl vs 8 cyl. You could only time the TDC of one of the cylinders to match the TDC of one of the plungers on the Duramax.

 

CP-3 is driven at half the speed of the crank that way engine compression and IP compression coincide every 720 degrees of crank rotation. The IP does not need to run at engine speed.

Its only the events that occur near the same time that cause the knock. The rest of the time the slack is out of the drive because there is only one event and you don't get the slap.

It doesn't matter how many cylinders as the compression stroke is the only critical event that needs to match the IP compression.

 

Does it matter which way you rotate the gear for phasing the pump? counterclockwise or clockwise? I'm pretty sure my truck is having this issue. Having trouble finding a video demonstrating. I have the gear puller and correct bolts. nut and washer is off, I just need to rotate and see