lb7 cp3

[05dmaxdriver]

My dads 02 has been having some issues with low power , did some logging yesterday . Well when he goes WOT commanded rail pressure is about 24000 psi ans actual rail pressure is 4000 at best . I think i found the problem .
How much of a pain is it to change a cp3 ?

 

[MoorePower]

Have you unhooked the regulator to rule that out?

 

[05dmaxdriver]

nope , just unplug it ?

 

[ZeroGravity58]

unplug it and you should see full pressure from the CP3.

 

[02bigstrokin]

to answer your original question, it sucks to change. nothing else needs to be said.

 

[05dmaxdriver]

k thanks

 

[05dmaxdriver]

unplugged regulator has full rail pressure at idle when unplugged any more suggestions ?

 

[BlkMax]

unplugged regulator has full rail pressure at idle when unplugged any more suggestions ?

You have two options, replace the regulator, or totally replace the pump.

I have only done the pump and it was a PITA, not really hard, just a PITA. I am not sure if you can change out the regulator without removing the pump. I was told by the stealer that you had to remove the pump to replace the regulator.

How many miles are on the pump? It depends on how long you think the pump will last if you just do the regulator. I had about 130k miles on the pump, so I replaced everything. While I had the CP3 out, I also did the water pump.

I found a lightly used II modded pump from Pat, so there was no core and I did not have to spend full price for a modded pump. It worked out well for me. I still have the old pump in a box in the shop.

 

[x MadMAX DIESEL]

What happens if you put the truck in drive with the regulator removed? Will the truck run away from you? I'd say don't try it but I'm asking for myself and not suggesting the OP to try it

 

[stroke250]

regulator can be replaced without removing the pump.

 

[S Phinney]

As pulse width goes up with a bad pump it will not keep up so by just unplugging the FPR does not mean that the pump is good if the pressure goes up. I would check for fuel restrictions in the tank pick-up also. Sometimes the pick-up will be clogged from black algae. The pump replacement will take up around 4-5 hrs to do without any experience in doing one.

 

[blowinsmoke]

low power from cp3

From a duramax tech at the local gm stealer, if your balance rates are good, between -4 and positive 4 on ll cylinders the pump is your problem. As ssaid before it is a large PITA and not for the faint of heart. Pensacola Diesel has them for 525 bucks with the new regulator. Best price i have found by far. Just put one on a friends a week ago and his truck had identical problems as yours. His truck screams now.

 

[05dmaxdriver]

K thanks guys looking like thats the problem !