have a 03 3500 dually crew, cant get over 13 mpg and I don't believe I have the towing power I should, the motor has 5" exhaust, efi live, and a banks big head dump valve actuator, I think my cp3 might be weak causing my problem, question is will putting a fass pump on correct this, is the cp3 repairable, or should it be replaced. also if it should be replaced do I go stock or what- thanks

 

If in fact your CP3 is waek then the only fix is to replace it ... what kind of fuel #'s are you viewing on scanner ??

Need to see Demand vs actual psi

 

im having a buddy scan it next week with a gm scanner, he said there is a stress test he can do with it, im just doing some beforehand investigating. so if it is bad where is a good place to get a reliable replacement, and are there upgrades available, are upgrades necessary?

 

he did a stress test tonight just sitting still and the rail pressure was terrible. to be positive he said he can pull the return on the cp3 and tell by the amount whether it is that or the injectors

 

i got my CP3 rebuilt by II aka industrial injection and i shimmed the fprv while it was down i sent my pump in and $790 total if you need injectors go to ether one of the two

injectors A... Merchant Automotive - Duramax LB7 Fuel Injector

injectors B... Web Store - Lincoln Diesel Specialties



CP3.. https://www.industrialinjection.com/...njection-pump/

shim guide.. https://www.dieselbombers.com/01-04-...-shim-mod.html

CP3 replacement password... daniel

CP3 replacement.. http://s219.photobucket.com/user/2500heavyduty/library/DIY/cp3%20replacement?sort=3&page=1

 

can anyone confirm whether a lmm cp3 will bolt right into a lb7, iheard they are a more reliable pump and they bolt right in.

 

they look the same but.... remember fuel pressure regulator is not the same so you would need EFI custom tune at minimum to make it work maybe a homemade adapter to connect it to the stock LB7 harness if you buy i rebuilt pump from industrial injection they all have the same upgraded parts inside them min will hold 28,000 psi on the rail if commanded by a Tech II i also shimmed the fuel pressure relief valve but anyway they are great reliable pumps