Need help with CP3 conversion

[Gen3Moe]

Hello, hope this message finds you well and Happy new year. I want some help regarding a problem in the fuel system that happened to my truck. My truck is a 2021 Ram 2500 6.7 cummins (early 2021 that came with a CP4 from the factory). I just purchased and installed the factory Y78 Recall package that converts it to CP3 ( Part # CSRLY781AA ) and I am having issues with the CP3. Fuel goes to the CP3 just fine, but the pump doesn’t send fuel to the rail. I disconnected the hard line that goes from the CP3 to the rail but no fuel came out of it and the truck cranks but doesn’t start (primed the pump and tried starting it like a million times). Do you know what may cause this problem? What areas should I be looking into and if there are any parts that need changing.


Note: truck is deleted and ran fine with the CP4 and I also installed a tune file for the CP3 conversion and the truck took the file without any issues.


Regards,

 

[sag2]

Are you sure the pump is actually turning? Can you look inside the access hole and confirm the pump shaft is turning when you crank it over. If the pump has supply, and the pump shaft is turning, unplug the FCA and crank with the pump to rail line loose at the rail. You should have fuel. Block off the intake somewhere convenient (like the boot to throttle valve) and it will crank over faster.

 

[sag2]

I guess I already know the answer (deleted), but why didn't you just have the recall completed?

 

[AH64ID]

I guess I already know the answer (deleted), but why didn't you just have the recall completed?

I was going to ask the same. Plenty of reports of deleted trucks getting the recall applied without issue.

 

[Gen3Moe]

Are you sure the pump is actually turning? Can you look inside the access hole and confirm the pump shaft is turning when you crank it over. If the pump has supply, and the pump shaft is turning, unplug the FCA and crank with the pump to rail line loose at the rail. You should have fuel. Block off the intake somewhere convenient (like the boot to throttle valve) and it will crank over faster.

Thank you for your reply, Unfortunately trucks that came with the cp4 have a different timing cover without an access hole. I checked my 3rd gen and even the gear housing is different on CGI’s.. I’ll go through everything again and do what you told me here.. thanks

 

[Gen3Moe]

I guess I already know the answer (deleted), but why didn't you just have the recall completed?

Truck ran fine with the delete before doing the recall. I didn’t do the recall because I didn’t know there was a recall as I live overseas in Kuwait and there isn’t a Cummins dealer here. Even the mopar dealer doesn’t offer parts and maintenance for diesel trucks. Instead we created a Cummins Owners Club and rented a storage for replacement parts and the club members do maintenance through us..

 

[Topzide]

@Gen3Moe, I know you got the file to take but when the recall is done here in the states, they flash new parameters to the ECM for the new pump setup. Might this be the issue happening? you may also need the new flash before you replace when the "tune". The tune may have been created with those parameters already being flashed. Something that you might also need to look into.

 

[Gen3Moe]

@Gen3Moe, I know you got the file to take but when the recall is done here in the states, they flash new parameters to the ECM for the new pump setup. Might this be the issue happening? you may also need the new flash before you replace when the "tune". The tune may have been created with those parameters already being flashed. Something that you might also need to look into.

Thanks for all the help you guys provided.. truck is up and running. After 3 hours of checking everything related to the CP3.. turns out rail pressure connector wasn’t locked in place

 

[Diesel85]

Glad to hear you got your truck up and running.

 

[Gen3Moe]

Glad to hear you got your truck up and running.

Appreciate it man

 

[sag2]

Glad you got it. A good scan tool would have caught that, and unplugging the FCA should have also made it start.

 

[Gen3Moe]

Glad you got it. A good scan tool would have caught that, and unplugging the FCA should have also made it start.

Thanks man, the scan tool gave me a “low fuel pressure code” I just thought it was because of the tune file lol.. glad I got rid of the CP4..