Fuel Injection Pump 4307021 for Cummins Engine B6.7 ISL9 L9 QSL9 Hyundai HX330L HX380L HX430L
This fuel pump is engineered as a direct replacement for the Cummins Engine B6.7 ISL9 L9 QSL9 Hyundai HX330L HX380L HX430L. Manufactured to meet or exceed OEM specifications, it delivers reliable performance in demanding conditions. Each unit is tested for fuel flow, pressure rating, and durability before leaving the factory to ensure consistent quality across every order.
Vehicle Compatibility
| Application | Details |
|---|---|
| Cummins Engine B6.7 ISL9 L9 QSL9 | See product specifications |
| Hyundai HX330L HX380L HX430L Replace Part Number: 4307021 Fit for Engine | See product specifications |
| Cummins B6.7 CM2350 B121B, ISL9 CM2350 L101, ISL9 CM2350 L111, L9 CM2350 L116B, L9 CM2350 L119B, L9 CM2350 L120C, L9 CM2350 L123B, QSL9 CM2250, QSL9 CM2350 L102, QSL9 CM2350 L118, QSL9 M CM2250 L106 Applications:Fit for | See product specifications |
| Hyundai Excavator: HX330L, HX380L, HX430L | See product specifications |
Replaces OEM Part Numbers
4307021 • Engine • Cummins • CM2350 • B121B • L116B • L119B • L120C • L123B • CM2250
Signs You Need a Replacement
If your equipment is showing any of these symptoms, the injection pump may be the cause:
- Engine cranks but won’t start — The pump may have lost prime or stopped delivering fuel. Check for fuel at the filter outlet before replacing the pump.
- Stalling under load — A weak pump can’t maintain pressure at high demand. The engine runs fine at idle but dies when you put it to work.
- Fuel pressure warning (if equipped) — Modern Cummins equipment monitors fuel rail pressure. A low-pressure warning often means the pump is failing.
- Loud whining from fuel system — A failing pump makes a high-pitched whine that gets louder as it warms up. Normal pump noise is a low hum.
- Air in fuel lines — If you see bubbles in the transparent fuel line or the primer bulb won’t stay firm, the pump may be drawing air through a worn seal.
- Excessive return flow — Too much fuel returning to the tank instead of reaching the injectors indicates internal pump wear.
Before You Replace the Pump
Before replacing the pump, check the fuel filter and fuel lines for restrictions. A blocked filter causes the same symptoms as a failing pump on Cummins equipment. When installing the new pump, fill it with clean fuel before connecting the lines — this reduces priming time and prevents dry-run damage. After installation, bleed the system fully and check for leaks at all connection points. Replace the fuel filter at the same time as the pump to protect the new unit from debris.
Frequently Asked Questions
Will this fit my Cummins HX330L?
Yes. This part is designed to fit the Cummins HX330L, HX380L, HX430L among other models listed in the compatibility table above. Verify your specific model and engine code before ordering to ensure the correct fit.
Can I cross-reference 4307021 with Engine?
Yes. Both 4307021 and Engine are interchangeable OEM numbers for this part. They refer to the same component with the same specifications, just different part number revisions.
How do I check if my engine code (HX330L, HX380L, HX430L) matches?
The engine code is stamped on a metal tag attached to the engine block, usually near the timing belt cover or on the cylinder head. Compare the code you find with the list above. Engine codes are 3 to 6 characters long.
How long does a Cummins fuel pump typically last?
Fuel pump life varies by application, but on Cummins equipment you can generally expect 5,000 to 10,000 hours of operation. Running the tank dry, using contaminated fuel, or neglecting the fuel filter are the top causes of premature failure.

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