When a diesel engine cranks too long, loses power under load, or shows unstable fuel pressure, the workshop often jumps straight to injectors. Sometimes that is right. Often it is not. The feed side of the fuel system deserves the same attention.
MLS Cummins carries CP2.2 High Pressure Gear Fuel Supply Pump 0440020115 0440020114 for applications that need a CP2.2 high pressure gear fuel supply pump, along with related line hardware such as Cummins ISDE Engine High Pressure Fuel Line Kit 4935976 4935982 4935981 4935974 and Cummins QSC8.3 High Pressure Fuel Line 3944686 3944690.
What the CP2.2 Fuel Supply Pump Does
The pump supports fuel delivery to the injection system so pressure and flow remain stable across idle, acceleration, and sustained load. If supply is weak, downstream components look guilty even when they are not.
Low Fuel Supply Symptoms
- Extended crank time after the vehicle sits.
- Poor response or hesitation under throttle.
- Loss of power at high load or high RPM.
- Intermittent rail-pressure faults with no confirmed injector defect.
- Engine stall after fuel demand rises suddenly.
| Symptom | Possible Supply-Side Cause |
|---|---|
| Hard start after overnight stop | Pump wear, fuel drain-back, air entry, or check-valve issue |
| Power loss only under load | Pump cannot maintain flow or upstream restriction exists |
| Rail pressure low and unstable | Weak feed supply or leaking pressure-control component |
| Improves after filter change, then returns | Contamination or pump wear still present |
Before You Condemn the Pump
- Inspect the fuel filter and water separator.
- Check for air intrusion on the suction side.
- Inspect the return circuit and relevant check valves.
- Verify that line fittings are tight and not partially restricted.
- Confirm actual supply pressure with a gauge or scan data where supported.
Where the Fuel Lines Fit In
A good pump cannot compensate for a bad line set. Damaged or mismatched high-pressure lines can alter delivery quality and create repeat failures. When the job involves line service, review Cummins ISDE Engine High Pressure Fuel Line Kit 4935976 4935982 4935981 4935974 and Cummins QSC8.3 High Pressure Fuel Line 3944686 3944690 at the same time.
When Pump Replacement Is the Right Move
Replace the pump when supply-side testing shows the unit cannot sustain proper delivery, when contamination has scored internal components, or when the pump leaks and fuel pressure cannot be stabilized. If debris is present, clean the system before fitting the new unit. Otherwise the new part inherits the old failure.
Part Matching Matters
Pump families can look similar on the bench. Mounting pattern, shaft design, pressure capability, and application tuning still differ. Use engine model, pump number, and cross-reference data together before ordering.
Related Control Parts Worth Checking
If shutdown complaints or unstable metering exist alongside low supply symptoms, inspect other fuel-control parts such as Engine Fuel Pump Shut-Off Solenoid Valve 3054610 3054609 4024809 196066 134074 and Denso Common Rail Pressure Limiting Valve CW095420-0422.
Related MLS Cummins Parts
- CP2.2 High Pressure Gear Fuel Supply Pump 0440020115 0440020114
- Cummins ISDE Engine High Pressure Fuel Line Kit 4935976 4935982 4935981 4935974
- Cummins QSC8.3 High Pressure Fuel Line 3944686 3944690
- Engine Fuel Pump Shut-Off Solenoid Valve 3054610 3054609 4024809 196066 134074
- Denso Common Rail Pressure Limiting Valve CW095420-0422
FAQ
Can a weak supply pump feel like an injector problem?
Yes. Under load, poor supply can reduce pressure and create smoke, hesitation, or power loss that resembles injector trouble.
Should lines be reused when replacing a fuel pump?
Only if they are confirmed clean, undamaged, and correct for the application.
What is the fastest mistake to avoid?
Replacing injectors first without verifying feed pressure, restriction, and air intrusion.
