DB4427-4950 3919103 Injection Pump for Cummins 4BT 3.9L

DB4427-4950 3919103 Injection Pump for Cummins 4BT 3.9L

The DB4427-4950 3919103 Injection Pump is a replacement mechanical diesel fuel injection pump designed for Cummins 3.9L B-Series diesel engine applications. It provides accurately metered fuel delivery to support reliable starting, stable operation and consistent engine performance.

Diesel injection pumps with a similar appearance may have different internal calibration settings. Please compare the complete pump number, Cummins part number, engine CPL and original pump nameplate before ordering.

Product Specifications

Cross-Reference Numbers

Compatible Engine and Application

• Cummins 3.9L B-Series diesel engine
• Cummins 4BT 3.9L engine applications
• Selected Cummins generator and industrial applications

Please confirm compatibility using the complete number on the original pump nameplate, the engine serial number and the Cummins CPL. Similar 3.9L engines may use injection pumps with different calibration and governor settings.

DB4427-4950 3919103 Injection Pump Features

• Designed as a replacement for the specified pump numbers
• Tested before shipment
• Accurate and stable diesel fuel delivery
• Mechanical DB-series rotary pump design
• Protective packaging for international shipping
• 12-month warranty

Installation Notice

Installation and timing adjustment should be completed by a qualified diesel technician. Before installation, inspect and clean the fuel tank, fuel lines and related fuel-system components, and replace the fuel filter when necessary.

Contaminated fuel or debris inside the fuel system may damage the replacement pump. Do not select the pump by appearance alone. Compare DB4427-4950, 3919103, the engine CPL and all information shown on the original pump tag.

Frequently Asked Questions

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Need Help Confirming Compatibility?

Browse more fuel injection pumps or submit the original pump number, engine model and engine serial number through our Request a Quote page.

DB4427-4950 3919103 Injection Pump identification and compatibility

The DB4427-4950 3919103 Injection Pump should be selected by part number and verified against the component removed
from the engine. Vehicle model names alone are not sufficient because the same model can use
different fuel-system versions in different markets or production periods. Compare the number
on the old component, connector layout, mounting points, fuel connections and the visible body
shape. Please confirm OE number, engine model or old part photos before ordering.

Practical checks before replacing this fuel injection pump

Hard starting, unstable idle, smoke, loss of power or unusual fuel consumption can have more
than one cause. A workshop should check fuel quality, supply pressure, return flow, wiring,
compression and related control components before deciding that replacement is required.
Diagnostic results should be considered together with the engine code and the number on the old
part. This avoids ordering by appearance only and helps distinguish a component fault from a
fuel-supply or electrical problem.

Installation and commissioning

Installation should be completed by a qualified diesel technician using clean tools and the
correct workshop procedure. Protect open fuel connections from contamination, replace required
seals, and follow the vehicle or engine manufacturer’s tightening and cleanliness instructions.
Some applications may require calibration data, coding, adaptation or relearn procedures, while
others do not. The applicable service information and diagnostic equipment should determine the
correct process for the specific engine.

Rayfuel supply and product support

The DB4427-4950 3919103 Injection Pump is supplied as an aftermarket replacement for professional diesel repair and parts
sourcing. Repair shops, distributors and wholesale buyers can review related products in the
fuel injection pump category. For quantity requirements or uncertain fitment, use the
Rayfuel contact page and include the OE number,
engine information and old-part photos. Packaging and shipping options can be discussed according
to the order quantity and destination.