A properly installed FASS fuel system significantly enhances diesel engine performance by delivering cleaner fuel at higher pressure, which extends the life of injectors and improves overall engine efficiency. However, achieving these benefits requires precise execution of each installation step. This guide provides a detailed overview of the installation process, emphasizing the importance of safety, accurate plumbing, and electrical setup. By following these instructions, users can ensure long-term reliability and optimal performance from their FASS system.
Installation Overview and Key Considerations
The installation of a FASS fuel pump system is more than just connecting components—it involves careful planning, preparation, and execution. The system includes a fuel pump assembly, reservoir tank, high-pressure fuel lines, return lines, and electrical components. The goal is to integrate these components into the vehicle's existing fuel system while ensuring leak-proof connections, secure mounting, and proper electrical grounding.
Key considerations during installation include:
- Safety first: Always disconnect all negative battery terminals to prevent electrical hazards.
- Depressurize the fuel system: Before beginning any work, release pressure from the high-pressure fuel rail to prevent injury from pressurized fuel.
- Follow kit instructions: Each FASS kit is tailored to a specific vehicle model, and manufacturers provide detailed installation guides. Deviating from these instructions can result in improper function or damage to the system.
Safety First: Pre-Installation Preparation
Before beginning the installation, it is crucial to take the necessary safety precautions to protect both the installer and the vehicle.
Disconnect Power Sources: Begin by disconnecting the negative battery terminal. For diesel trucks with multiple batteries, disconnect all negative terminals. Ensure that the disconnected cables are placed in a location where they cannot accidentally come into contact with the terminals. This step is essential to prevent electrical shock or sparks near the fuel system.
Depressurize the Fuel System: Locate the factory fuel pressure test port, which is typically a Schrader valve on the high-pressure fuel rail. Cover the valve with a thick rag and use an appropriate tool to slowly depress the valve core. This will release any residual pressure in the system. Be prepared to catch any fuel that may spray out during this process. Never skip this step, as pressurized fuel can cause serious injury.
Mounting the FASS Pump Assembly
Proper mounting of the pump assembly is essential for both performance and longevity. The pump should be mounted in a location that is secure, accessible, and free from excessive vibration or heat exposure.
Position Verification: Place the pump assembly in the intended location and verify that the port orientations align with the planned fuel line routing. Ensure that there is adequate clearance around the assembly to allow for proper operation and future maintenance.
Surface Preparation: Clean the mounting surface thoroughly with brake cleaner to remove any dirt, grease, or debris. This ensures a secure and stable installation.
Secure Mounting: Using the provided bracket and hardware, bolt the pump assembly to the frame rail. Ensure that the bracket and assembly are solid and free from excessive flex. Tighten the hardware to the manufacturer's specifications to prevent loosening over time.
Plumbing the Fuel System
The plumbing of the fuel system involves connecting the reservoir tank, pump inlet, and outlet lines, as well as the return line. Each connection must be leak-free and properly secured to prevent fuel leaks and ensure consistent pressure.
Reservoir Tank to Pump Inlet (Supply Line): Run the provided braided supply hose or push-lock hose from the reservoir tank outlet port to the inlet port on the FASS pump assembly. Ensure that the hose length is sufficient for gentle curves without stretching or kinking. Use high-quality hose clamps at each connection point, securing them tightly but without overtightening to avoid crushing the hose barb.
Pump Outlet to Engine Fuel System (Discharge Line): Run the provided discharge hose (usually braided stainless or high-pressure push-lock) from the outlet port on the FASS pump assembly along the pre-planned route towards the engine bay. Aim to connect as close to the engine fuel rail as possible, often connecting to the existing engine bay fuel supply line using appropriate fittings provided in the kit. Ensure that the connection is after the factory lift pump (if equipped) but before the high-pressure CP3/CP4 pump inlet. Tighten all connections securely and use thread sealant only where specified. Avoid applying sealant on flare fitting cones, O-rings, or NPTF threads that rely on interference for sealing.
Secure the Discharge Line: Secure the discharge line every 12–18 inches along its path to prevent movement or damage. Avoid routing the line near heat sources or sharp edges that could cause wear or chafing over time.
Pump Return (Bypass/Regulator) Line to Vehicle Return System: Locate the vehicle's fuel return system, typically found at the fuel pressure regulator cap on top of the secondary fuel filter housing. FASS kits provide specific fittings to adapt into this return system. Common methods include replacing the factory filter cap with an FASS cap that includes additional return ports or using a tee fitting spliced into the factory return line near the filter head. Follow the kit instructions precisely for your vehicle model, as incorrect plumbing can prevent the pump from regulating pressure properly.
Electrical Wiring and Power Setup
Proper electrical wiring is critical for the reliable operation of the FASS fuel pump. Incorrect installation is a leading cause of premature pump failure, so it is important to follow the manufacturer's guidelines carefully.
Mount Relay and Fuse Holder: Secure the relay module and fuse holder assembly in a location within the engine compartment that is away from direct water spray, mud, and heat. Ensure that the mounting is robust to resist vibration and movement.
Connect Power Source: Connect the power source to the relay module according to the manufacturer's instructions. Ensure that the wiring is properly insulated and secured to prevent short circuits or electrical interference.
Post-Installation Checks and Initial Operation
After the installation is complete, it is essential to perform a series of checks to ensure that the system is functioning correctly and that all connections are secure.
Observe Fuel Pressure (If Gauge Installed): If the system includes a fuel pressure gauge, verify that the pressure reading aligns with the pump specifications and engine requirements. Initial adjustments may be necessary after a short period of operation.
Pressure Adjustment (Fixed Pressure Systems): If the FASS system includes an adjustable pressure regulator, avoid making significant adjustments until after a short test drive and monitoring of the system. Consult the specific kit instructions if any adjustments are needed.
Monitor Fluid Levels: Keep an eye on the reservoir tank level and overall vehicle fuel gauge during the initial operation. Ensure that the system is not running low, as this can cause air to be drawn into the pump and lead to damage.
Scan for Codes: Use an OBD-II scanner to check for any new diagnostic trouble codes (DTCs) that may have been triggered during installation. Clear any spurious codes and address any persistent codes according to the manufacturer's recommendations.
First Road Test
After the installation is complete and the system has been checked, it is time for the first test drive. This test should be a short, gentle drive to monitor the system's performance and identify any issues.
Engine Performance: Pay attention to the smoothness, power delivery, and starting performance of the engine. The FASS system should enhance these aspects, and any irregularities should be investigated.
Pump Noise: Listen for consistent pump noise at various speeds. Any excessive vibration or unusual noise should be addressed immediately.
Leaks: Re-inspect the entire system after the drive, especially when components are hot. Look for any signs of fuel leaks or loose connections.
Fuel Pressure Stability (If Gauge Installed): If the system includes a fuel pressure gauge, monitor the pressure during the test drive to ensure stability. Any fluctuations could indicate an issue with the system.
Controller Calibration/Tuning (If Applicable): Follow the FASS instructions precisely for initial setup and tuning procedures of adjustable systems. This often involves setting base pressures based on sensor readings.
Long-Term Reliability and Maintenance
To ensure the long-term reliability of the FASS fuel system, it is important to follow a few key maintenance practices.
Avoid Running Dry: Never allow the reservoir tank to run dry. This can cause air to be drawn into the pump, leading to damage. Monitor the fuel gauge regularly and refill as needed.
Use High-Quality Fuel and Filters: Use clean, quality ULSD fuel and adhere strictly to the FASS filter change intervals. Filters are critical to the pump's longevity, so they should be changed at the recommended intervals, regardless of driving conditions. In dusty or contaminated environments, consider reducing the intervals.
Prime the System After Filter Changes: Always prime the system using the pump's prime/vent procedure after changing filters. This ensures that the system is properly filled and ready for operation.
Monitor Reservoir Tank Drains: Some tanks include drain plugs for removing water or debris that may settle at the bottom. Periodically drain a small amount into a clear container to check for contaminants, especially if fuel quality is uncertain.
Visual Inspections: Make it a habit to visually inspect the system regularly, such as during oil changes. Look for signs of damage, chafing, kinks, or cracks in the fuel lines, especially near heat sources or movement points. Check all fittings and clamps for tightness and signs of seepage. Inspect wiring harnesses for damage or chafing, and verify that the pump and reservoir mounts are secure.
Extended Storage: If the vehicle will be stored for an extended period, run the system periodically to lubricate the pump internals and prevent varnishing. Consult FASS for specific storage recommendations to ensure the system remains in optimal condition.
Conclusion
A professional-grade installation of a FASS fuel pump system is a critical step in maximizing diesel engine performance and longevity. By following the detailed procedures outlined in this guide, users can ensure that their installation is precise, safe, and reliable. The benefits of a properly installed FASS system include cleaner fuel delivery, higher pressure, improved injector life, and enhanced overall engine performance. With proper maintenance and attention to detail, the FASS system can provide reliable service for hundreds of thousands of miles, making it a valuable investment for any diesel engine enthusiast or professional.