Hey everyone...great forum you got here.
I recently bought my first dodge diesel: 03' CTD Quad-cab LB 4x4
Obviously this is my first post...and i have a real noob of a first question.

Whats a cp3? And what does it do?

Im not new to mechanics...ive wrenched all my life...i just dont know anything about diesels.

I have a "stumble/stutter" at start up in the mornings, with a little excessive "knock" until the engine warms up a bit. It started after i took my truck to the dealer..and they replaced my fuel pump with the in-tank version, long story about the dealer, but lets just say im never gonna let them touch my truck again. Hope to hear what you guys think.
THANKS!

 

CP3 is your fuel injection pump. there are two fuel pumps on the truck. they replaced your lift pump. The CP3 is up on the side of the engine on the driver side

 

Hey I just wanted to say WELCOME TO DTR!
Yeah if you will look around on the website, you will notice that a lot of other people won't take their trucks to the dealer again. Thats what this website is good for...if you are a good mechanic, you can get practically everything you need to know from this website!

 

so where was my original lift pump located?

reason i ask was the dealer told me that they replaced a fuel pump that was bad but they said it was in the same location as you just described....driver side engine compartment. are the lift pump and cp3 close to one another in the stock configuration? sorry for my ignorance...im learning fast.

whats a cp3 look like?

 

the cp3 is mounted on the drivers side of the motor. it is the high pressure fuel pump. just follow your injector lines.
sound like you might have a bad injector or a bad pressure relief valve. i would reccomoned a diesel shop to do the work. a good shop can rebuild your stock injectors.

 

The lift pump is what was replaced if you say it was installed in the fuel tank. Originally your truck came with the fuel filter canister mounted lift pump. The upgrade now goes in the fuel tank. Both the CP3 injection pump and the original lift pump are on the driver side of the engine. The CP3 is on the very front of the engine and as I mentioned previously,the lift pump was mounted at the fuel canister. Since you had the in tank upgrade the original lift pump location on the filter canister would now be blocked off. Do a search on the CP3 pump and lift pump on this Gen III forum and you will find some pictures. I hope this helps you out.

 

thanks guys!!

 

The early third generation common fuel rail Cummins (03-04) had the lift pump on the fuel filter and a relatively high failure rate. I believe in 04 1/2 they moved the lift pump to the fuel tank and there are still a few failures. The greatest problem with the in tank version is if the lift pump fails it is much more difficult to access and replace than the filter mounted one. There are many threads about completely replacing the factory lift pumps with aftermarket that are more reliable. Do a advanced search for walboro or lift pumps and you will find a myriad of threads about this topic.

The original lift pump on your truck was located on the back side of the fuel filter facing toward the firewall. When the dealer installed the in tank version lift pump they removed the old lift pump (or at least let's hope they did) and installed a adapter block in it's place. The block should be either round or rectangular near the top of the filter housing with no electrical wires connected to it and a fuel line going to it.

Good luck and enjoy your "new to you" truck.

L8r,...........dogger