0445120121
BOSCH 0445120121 Common Rail Injector for Cummins ISB / QSB 6.7L & Dongfeng Tianlong
4940640, 4940170, 5263308, C4940640F00RJ01941DLLA142P17091600 barProduct Overview
The Bosch 0445120121 is a heavy-duty CRIN2-16 common rail diesel fuel injector engineered for commercial heavy trucks, buses, and off-highway industrial machinery powered by Cummins ISB 6.7L, QSB 6.7L, and DCEC ISDe 6.7L engines. Widely deployed across Dongfeng Tianlong, Dongfeng Kingrun, Foton Auman, and SANY industrial excavator applications, this solenoid-driven injector operates at injection rail pressures up to 1600 bar. Internal hydraulics feature precision control valve F00RJ01941, hole-type nozzle 0433172047 (stamped DLLA142P1709), and magnet assembly F00RJ02697, providing millisecond-accurate pilot and main fuel delivery. Built for Euro 3 and Euro 4 emission standards, installation requires strict adherence to connector tube alignment procedures and entry of the unique IMA calibration code into the ECM.
CONNECTOR TUBE TORQUE SEQUENCE: Never torque the hold-down clamp before seating the high-pressure connector tube. Pre-tighten the connector tube retaining nut to 15 N·m first to center the spherical sealing interface with the injector inlet port, tighten the hold-down clamp bolt to 24 N·m, and finally torque the connector tube to 50-55 N·m to prevent internal high-pressure leakage into the valvetrain and DTC P0087.
Vehicle & Engine Fitment
| Vehicle | Engine | Years |
|---|---|---|
| Dongfeng Tianlong / Kingrun 6.7D | Cummins ISB / QSB 6.7L (ISDe / Komatsu SAA6D107E) | 2007-2016 |
| Foton Auman ETX / GTL Heavy Truck | Cummins ISB / QSB 6.7L (ISDe / Komatsu SAA6D107E) | 2008-2016 |
| SANY SY215 / SY235 Excavator & Mixer | Cummins ISB / QSB 6.7L (ISDe / Komatsu SAA6D107E) | 2008-2018 |
| Yutong ZK Heavy Commercial Bus & Coach | Cummins ISB / QSB 6.7L (ISDe / Komatsu SAA6D107E) | 2007-2015 |
Technical Specifications
| Specification | Value |
|---|---|
| Fuel System | Bosch Common Rail (CRIN2-16) |
| Peak Pressure | 1600 bar |
| Control ValveCore Spec | |
| Nozzle CodeCore Spec | |
| Nozzle Part NumberCore Spec | |
| Magnet Assembly | F00RJ02697 |
| Seal Ring Kit | F00RJ02176 |
| Connector Tube Pre-Torque | 15 N·m |
| Hold-down Clamp Torque | 24 N·m📐 Torque & Angle Wizard → |
| Connector Tube Final Torque | 50-55 N·m |
| High Pressure Line Torque | 30-35 N·m |
| Coding Standard | Bosch IMA (6/7-Character Alphanumeric) |
| Operating PressureCore Spec |
Installation Tips
Tools needed: Calibrated torque wrench and line crowfoot tool, Brass injector bore seat brush kit and industrial vacuum extraction unit, Dedicated electronic diagnostic tool for IMA/injector coding
- Thoroughly ream and clean the cylinder head injector well down to bare metal using a specialized brass seat brush; blow out all carbon deposits and confirm zero debris remains.
- Fit a genuine new copper sealing washer of correct thickness (standard 1.5mm) onto the nozzle tip, and install a brand-new viton O-ring onto the injector body lubricated with clean engine oil.
- Lower the 0445120121 injector assembly straight into the bore, aligning the side fuel inlet port toward the cylinder head connector tube port, and snug the hold-down clamp bolt finger-tight (approx 3-5 N·m).
- Insert a new or meticulously inspected high-pressure connector tube (feed tube) through the cylinder head, and torque the connector tube retaining nut to the preliminary alignment specification of 15 N·m.
- Torque the injector hold-down clamp bolt to its final torque of 24 N·m to securely seat the copper washer against the cylinder head seat.
- Finalize torque on the high-pressure connector tube retaining nut to 50-55 N·m to establish a high-pressure metal-to-metal spherical seal.
- Connect the high-pressure fuel rail line using the 2-wrench counter-hold method, torque the line nut to 30-35 N·m, plug in the electrical solenoid harness, and programme the unique IMA calibration code into the ECM via diagnostic tool.
- High-Pressure Feed Tube Alignment Risk: Tightening the hold-down clamp bolt to 24 N·m before installing the feed tube will misalign the spherical sealing joint. This misalignment creates high-pressure internal fuel leakage into the valvetrain, leading to extended cranking, power loss, and fault code P0087. Always maintain the 15 N·m -> 24 N·m -> 50-55 N·m torque progression.
- Inspect Feed Tube Sealing Tip: Whenever replacing injector 0445120121, examine the brass/steel spherical tip of the high-pressure connector tube. Any edge erosion, scratching, or flattening necessitates replacing the connector tube assembly (Cummins 4929864 / 3957087) immediately; reusing damaged tubes causes immediate rail pressure loss.
- 2-Wrench Line Torquing Mandate: When tightening the high-pressure fuel rail line to 30-35 N·m, always counter-hold the connector tube retaining nut with a second open-ended wrench. Unopposed torque can twist the connector tube or crack the injector body fuel inlet socket.
Frequently Asked Questions
What symptoms indicate a failing Bosch 0445120121 injector on Cummins ISB / QSB engines?
Common failure indicators include hard starting or long cranking when warm due to excessive dynamic backleakage past control valve F00RJ01941, black exhaust smoke under acceleration caused by worn nozzle DLLA142P1709 orifices, engine knocking under load, and diagnostic trouble code P0087 (Fuel Rail Pressure Too Low).
Is ECU coding required after installing injector 0445120121?
Yes. The 0445120121 injector features an individually calibrated alphanumeric IMA code laser-etched onto the electrical connector head. This code must be written to the engine ECM (Cummins INSITE or commercial truck scanner) to enable individual cylinder fuel volume and timing corrections.
What are the common OE cross-reference numbers for 0445120121?
Primary OE part numbers include Cummins 4940640, 4940170, 5263308, and Dongfeng DFM C4940640.
What dynamic backleak rate is acceptable during bench testing?
At normal operating temperature under full load (1600 bar), maximum permissible return leakage should not exceed 45 ml/min per injector. Dynamic backleakage exceeding 50 ml/min confirms internal seat wear in control valve F00RJ01941, causing rail pressure drop and hot-restart refusal.
What is the correct coil resistance for solenoid testing?
Using a calibrated digital multimeter at 20°C ambient temperature, measurement across the two solenoid pins must indicate 0.25 to 0.50 Ohms. Resistance below 0.20 Ohms indicates shorted internal windings, while resistance above 0.60 Ohms indicates degraded terminal bonding, either of which triggers solenoid circuit DTCs P0201-P0206.
Diagnostic Trouble Codes & Fault Protocols
Common diagnostic trouble codes (DTCs) triggered when this common rail injector experiences wear, circuit faults, or calibration drift:
Fuel Rail / System Pressure Too Low
Excessive internal backleak from worn control valve seats drops common rail pressure below target under engine load.
Injector Circuit Malfunction / Open Circuit
Solenoid coil resistance drift (0.2-0.5 Ω) or piezo stack degradation triggers driver stage shutdown on affected cylinders.
Cylinder Misfire & Balancing Deviation
Carbon-clogged nozzle spray holes or missing IMA calibration causes uneven cylinder contribution. Recode ECM and verify washer seating.
Fuel Rail / System Pressure Too High
Spill line backpressure or stuck metering valve prevents rail depressurization, creating overpressure risks under load.
Cross-Reference & Compatibility
Sister parts, same-platform variants, and known incompatibilities.
Technical Diagnostic & Service Protocols
Authoritative field procedures, diagnostic testing thresholds, and service SOPs for this assembly.