Fuel leak at CP3 pump

[Sixpac2]

Hi,

04. 5 with 99k now.

Noticed when changing tran fliud that at the fron diff cover looked wet.

After further investigating found below the CP3 pump looks wet.

Wire harness and the other is wet.

Looked at CP# from below and side with wheel liner off and from the top.

all lines are tight and does not appear to be coming from there.

is this a 1 piece or 2 piece unit.

It is hard to see but appears that the main body to the rear mounts to a larger piece toward the front????



Is there seals that can go bad??



I did notice some fuel stain earlier but appears to be getting worse.



Any ideas or leads on what to do now would help.



Thanks, Marv

 

[Sixpac2]

Here is what the manual states.

When looking what is the fuel/gear pump and the injector pump????











Fuel enters the system from the electric fuel transfer

(lift) pump, which is attached to the fuel filter

assembly. Fuel is forced through the fuel filter element

and then enters the Fuel Pump/Gear Pump,

which is attached to the rear of the fuel injection

pump. The Fuel Pump/Gear Pump is a low-pressure

pump and produce pressures ranging from 551. 5 kpa

(80 psi) to 1241 kpa (180) psi. Fuel then enters the

fuel injection pump. Low pressure fuel is then supplied

to the FCA (Fuel Control Actuator).

The FCA is an electronically controlled solenoid

valve. The ECM controls the amount of fuel that

enters the high-pressure pumping chambers by opening

and closing the FCA based on a demanded fuel

pressure. The FPS (Fuel Pressure Sensor) on the fuel

rail monitors the actual fuel pressure and provides it

as an input to the ECM. When the actuator is

opened, the maximum amount of fuel is being supplied

to the fuel injection pump. Any fuel that does

not enter the injection pump is directed to the overflow

valve. The overflow valve regulates how much

excess fuel is used for lubrication of the pump and

how much is returned to the tank through the drain

manifold.

Fuel entering the injection pump is pressurized to

between 300-1600 bar (4351-23,206 psi) by three

radial pumping chambers. The pressurized fuel is

then supplied to the fuel rail.

 

[TCDiesel]

Hi,

04. 5 with 99k now.

Noticed when changing tran fliud that at the fron diff cover looked wet.

After further investigating found below the CP3 pump looks wet.

Wire harness and the other is wet.

Looked at CP# from below and side with wheel liner off and from the top.

all lines are tight and does not appear to be coming from there.

is this a 1 piece or 2 piece unit.

It is hard to see but appears that the main body to the rear mounts to a larger piece toward the front????



Is there seals that can go bad??



I did notice some fuel stain earlier but appears to be getting worse.



Any ideas or leads on what to do now would help.



Thanks, Marv

It needs to be removed and New Seals and O-rings install, it requires Special tools to separate and repaired. . One mistake and BOOM.

 

[Prairie Dog]

This leak seems like a common failure mode. Is it possible to just have the seal or gasket replaced without going through the whole thing?

 

[Sixpac2]

TC

when you say removed and seals and orings replaced.

are these internal to the assembly?



In the service manual it shoes how to remove the whole unit from the timing gear housing.



Them are you saying the injector pump needs to come apart??



Thanks

 

[JJPage]

Cold weather appears to make some CP3's leak, warm weather they stop. The most prevalent place the leak seems to happen, is between the gearpump case and the main body of the CP3 housing.

There is an o-ring seal between the two units, it is a one piece o-ring comprised of three rings, small ring, large ring, small ring. No special tools required(torx), but you do need an agile body, removing the driver's side inner fender well is a good start. If you scroll down to the end of this post, you can see where that o-ring gasket belongs. Relentless Diesel • View topic - DIY CP3 Mods As you can see from the post, the leak can also be between the gearpump case halves.

 

[Sixpac2]

hey out there,

After further searching.

On other forums as well I seem a common issue with the seals leaking due to one part being aluminum and the other metal.



Are others buying new pumps or rebuilding with new seals.



If so who and where to get done????



Thanks

 

[LFarmer]

Mine was replaced under warranty for the same leak. Fuel had soaked the connector for the fan clutch and set a fan clutch code. I'm sure getting the seals replaced is cheaper than a whole new pump.

 

[TCDiesel]

Their are 18 O-rings and 3 seals in every 5. 9 Pump. . If the 2 eccentric seals are leaking you would be making oil. You can just R/R your pump if it specs out about $300. 00. You will Need a gear Puller and Barring Tool (Barring Tool Optional) Dodge Cummins CP3 Installation just click on the pump to open download and chose Download/Open.