BOSCH Diesel Injection Pump 9400-030-723

( Brand: Bosch ), ( Manufacturer Part Number: 9400030723 ), ( Type: Fuel Injection Pump ), ( Country Of Origin: United States )

Review BOSCH Diesel Injection Pump fits CUMMINS

The **Bosch 9400030723 Cummins 9400-030-723 (3929404) Diesel Injection Pump** is a high-performance, precision-engineered component designed exclusively for Cummins diesel engines, specifically tailored to models requiring the **3929404** part number. This robust injection pump is a critical element of the fuel delivery system, ensuring optimal combustion efficiency, power output, and emissions compliance. Built to Bosch s exacting standards, this pump incorporates a **rotary distributor design**, which delivers fuel under high pressure to the engine s cylinders in a precise, timed sequence, maximizing both performance and fuel economy. Constructed from durable materials, including hardened steel components and corrosion-resistant alloys, it is engineered to withstand the demanding conditions of heavy-duty applications, such as commercial trucks, marine vessels, and industrial equipment. The pump s internal components, including the **camshaft, plunger assembly, and fuel control mechanism**, are meticulously machined to minimize wear and prevent fuel leakage, thereby extending the lifespan of the engine and reducing maintenance requirements. Whether installed in a **Cummins ISB, ISL, or other compatible models**, this injection pump delivers reliable, consistent fuel delivery, contributing to smoother operation, reduced emissions, and enhanced fuel efficiency. Its compatibility with Cummins engine management systems ensures seamless integration, making it an essential replacement part for fleets and operators seeking dependable performance in demanding environments.

### **Bosch CP3.7 (9400030723 / 9400-030-723 / 3929404) Diesel Injection Pump: Pros and Cons**

#### **Overview**

The **Bosch CP3.7 (Common Rail) diesel injection pump** (part numbers: 9400030723, 9400-030-723, 3929404) is a high-pressure fuel injection system designed for modern diesel engines, particularly those using **Cummins ISX, ISL, or similar heavy-duty applications**. It is a critical component for precise fuel delivery, emissions compliance, and engine performance.

---

### **Pros**

1. **High Precision Fuel Injection**

- Uses **common rail technology**, allowing for **variable injection timing, multiple injections (pilot, main, post-injection)**, and **high injection pressures (up to 2,000 bar)**.

- Improves **combustion efficiency**, reducing **soot and NOx emissions** while maintaining power.

2. **Durability & Reliability**

- Bosch is a **leading manufacturer** in fuel injection systems, known for **long-lasting components** when properly maintained.

- Designed for **high RPM and heavy-duty applications**, making it suitable for **trucks, buses, and industrial engines**.

3. **Emissions Compliance**

- Supports **modern emissions standards (EPA 2010, Euro VI, etc.)** by enabling **precise fuel metering and advanced injection strategies**.

- Helps meet **lower particulate and NOx limits** without significant power loss.

4. **Compatibility with Modern Engines**

- Works well with **Cummins ISX, ISL, and other heavy-duty diesel engines** that require **high-pressure common rail systems**.

- Often used in **aftermarket upgrades** for **power increases and better fuel economy**.

5. **Aftermarket & Remanufacturing Availability**

- **OEM-quality remanufactured units** are widely available from **Bosch, Cummins, or third-party suppliers**, reducing costs compared to new.

- **Easier to source spare parts** than older mechanical pumps (e.g., Bosch VE or P pump).

6. **Fuel Efficiency Improvements**

- **Optimized injection timing** can lead to **better fuel atomization**, reducing **fuel consumption** in properly tuned engines.

7. **Compatibility with Turbocharging & EGR Systems**

- Works well with **modern turbocharged and EGR-equipped engines**, which are common in **heavy-duty diesel applications**.

---

### **Cons**

1. **High Cost (New Unit)**

- A **new Bosch CP3.7 pump** can cost **$1,500 $3,000 **, depending on the engine application.

- **Remanufactured units** are cheaper ( $800 $1,800) but may require **additional diagnostics** to ensure quality.

2. **Complexity & Tuning Requirements**

- Unlike older **mechanical pumps (Bosch VE, P pump)**, the **CP3.7 requires proper ECU tuning** for optimal performance.

- **Incorrect tuning** can lead to **poor fuel economy, rough idle, or even engine damage**.

- **Aftermarket ECU upgrades (e.g., Haltech, Link, Snappy) may be needed** for best results.

3. **Sensitivity to Fuel Quality**

- **Contaminated or low-quality diesel** can clog **injectors and fuel passages**, leading to **poor performance or failure**.

- Requires **high-quality fuel filters and regular maintenance**.

4. **Potential for Failure in High-Mileage Engines**

- If the **original pump was neglected**, it may have **internal wear (worn solenoids, leaking seals, or clogged nozzles)**.

- **Diagnostic tools (e.g., Bosch KTS, Snap-on MSD) are needed** to confirm pump health before replacement.

5. **Compatibility Issues with Older Engines**

- Not all **older Cummins engines** (pre-2000s) are designed for **common rail systems** some may require **ECU or wiring modifications**.

- **Aftermarket adapters or custom wiring** may be necessary in some cases.

6. **Limited DIY Repairability**

- Unlike **Bosch VE pumps**, the **CP3.7 is not easily serviced by non-specialists**.

- **Remanufacturing or professional repair** is often required, increasing costs.

7. **Potential for Emissions-Related Issues**

- If the **EGR, DPF, or SCR system is failing**, the **pump alone won t fix emissions-related problems**.

- **Modern engines may require full system diagnostics** before pump replacement.

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### **Conclusion & Recommendation**

**You have a modern Cummins ISX/ISL engine (2000s present) with emissions concerns.**

**Your engine has poor fuel economy, rough idle, or misfires due to a failing pump.**

**You re upgrading an older mechanical pump (VE/P) for better performance and emissions compliance.**

**You have access to proper diagnostics (Bosch KTS, Snap-on, or equivalent) to confirm pump failure.**

**You re willing to invest in tuning (OEM or aftermarket ECU) for optimal performance.**

**Your engine is very old (pre-2000s) and not designed for common rail may require full rebuild.**

**You lack diagnostic tools or mechanical skills to properly install and tune the pump.**

**The engine has other major issues (worn injectors, bad turbo, failing DPF/EGR) that need addressing first.**

**You re on a tight budget consider a **remanufactured unit** or **used OEM pump** instead of new.**

**You re not prepared for potential **ECU or wiring modifications** if the engine isn t factory-compatible.**

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### **Final Recommendation**

**If you have a modern Cummins engine with confirmed pump failure and access to proper diagnostics/tuning, the Bosch CP3.7 is a **solid upgrade** for better fuel efficiency, power, and emissions compliance.**

1. **Confirm pump failure** with a **Bosch KTS or equivalent diagnostic tool** (common rail pumps often fail due to **worn solenoids, leaking seals, or clogged nozzles**).

2. **Choose a remanufactured unit** (e.g., from **Bosch, Cummins, or a trusted remanufacturer**) to save money.

3. **Ensure ECU compatibility** may need **OEM or aftermarket tuning** (e.g., **Haltech, Link, or Snappy**).

4. **Use high-quality fuel filters and maintain fuel system** to prevent future issues.

5. **Consider a full fuel system flush** if the engine has been neglected.

- If the engine is **very old or has other major issues**, a **full engine rebuild** or **replacement pump injectors** may be more cost-effective.

- For **budget-conscious buyers**, a **used OEM pump** (from a trusted source) can be a cheaper alternative.

The **Bosch CP3.7 is a high-quality, reliable upgrade** for modern Cummins engines, but it requires **proper diagnostics, installation, and tuning** to perform optimally. If you re unsure, **consult a diesel specialist** before purchasing.

Details:

LOT# 34261 1 BOSCH 9400 030 723 CUMMINS 3929404 NEW TAKE OFF - MISSING A FEW COMPONENTS.

part #: 9400030723 prices

• $500.00-$2541.00

specifications carfuelinjector:

• for models: Cummins
• brand: Bosch
• mpn: 9400030723
• type: Fuel Injection Pump
• country of origin: United States

shipping carfuelinjector:

• type: Calculated
• class: Standard
• transit: 5-10 Days
• cost: $85.90
• carrier: USPS
• service: USPS Ground Advantage

returns carfuelinjector:

• policy: Returns Accepted
• paid by: Seller
• time: 30 Days

offer carfuelinjector:

• started: April 29, 2026
• quantity: 1
• availability: In Stock
• sold: 0
• options: Ship-to-home

seller carfuelinjector:

• # reviews: 3162
• city: Elm City, North Carolina
• rating: 100.0%

general carfuelinjector:

• Air Fuel Delivery > Fuel Injection Parts > Fuel Injectors
• condition: New other see details

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