Chevy Small Block EFI Conversion

Revitalising Your Classic: carbureted to EFI with FiTech

The allure of a classic Chevrolet small block engine is undeniable. Their robust nature and distinctive rumble have powered countless iconic vehicles. However, for many enthusiasts, the age-old carburettor can present a significant hurdle. From cold start issues to fiddly tuning and less-than-ideal fuel economy, carburettors, while charming, are often outpaced by modern demands. This is where the appeal of Electronic Fuel Injection (EFI) truly shines. The prospect of improved drivability, enhanced fuel efficiency, and a more consistent power delivery is incredibly tempting. One popular route for this transformation is the FiTech EFI system, often marketed as a straightforward upgrade for carbureted engines. But is it as simple as it seems? Let's delve into the process of converting a carbureted small block Chevy to a FiTech EFI system, addressing potential challenges and offering insights for a successful upgrade.

Why Make the Switch to EFI?

Before diving into the specifics of FiTech, it's worth understanding the fundamental advantages of EFI over carburetion. Carburettors rely on the Venturi effect to draw fuel into the airstream, a process that is inherently less precise than EFI. EFI systems use sensors to monitor crucial engine parameters such as air intake temperature, engine coolant temperature, throttle position, and manifold pressure. A computer, or Engine Control Unit (ECU), then precisely calculates the optimal amount of fuel to inject through electronic injectors, ensuring a perfect air-fuel ratio under all conditions. This leads to:

• Improved Fuel Economy: More precise fuel delivery means less wasted fuel.
• Better Drivability: Smoother idle, instant throttle response, and easier cold starts.
• Increased Horsepower and Torque: The engine can operate at its peak efficiency more often.
• Easier Emissions Compliance: EFI systems are inherently better at meeting modern emissions standards.
• Self-Tuning Capabilities: Many modern EFI systems can adapt to changes in altitude and temperature.

Introducing the FiTech EFI System

FiTech offers a range of EFI systems designed to be a direct bolt-on replacement for most carburettors, typically using the familiar Square Flange or Holley bolt pattern. Their systems often include a throttle body with integrated fuel injectors, a fuel pressure regulator, and a control unit that manages the fuel delivery. Some kits also come with essential components like a wiring harness and a distributor, simplifying the installation process. The promise is a modern, efficient fuel delivery system that can be fitted by the home mechanic with basic tools.

The Conversion Process: What to Expect

Converting a carbureted small block Chevy to a FiTech EFI system generally involves several key steps:

1. Fuel System Upgrade: EFI systems require a higher and more consistent fuel pressure than carburettors. This often necessitates the installation of a new fuel pump (in-tank or external), fuel lines, and a suitable fuel filter.
2. Throttle Body Installation: The FiTech throttle body will replace your existing carburettor. This usually involves connecting the throttle linkage and any necessary vacuum lines.
3. Wiring: The EFI system will require a power source, ground, and connections to various sensors. FiTech systems typically come with a straightforward wiring harness.
4. Distributor (if applicable): Some FiTech kits include a new distributor that integrates with the EFI system for timing control. If you're retaining your existing distributor, ensure it's in good working order and compatible.
5. Sensors: The EFI system will require sensors such as a throttle position sensor (TPS), manifold absolute pressure (MAP) sensor, and potentially others depending on the specific kit.
6. Initial Setup and Tuning: Once installed, the system will need to be configured. Many FiTech systems feature a handheld controller that allows for initial setup and basic tuning.

Potential Pitfalls and How to Avoid Them

While the idea of a simple bolt-on EFI conversion is appealing, it's crucial to be aware of potential challenges. The review provided highlights some common issues that can arise:

• Component Quality: As noted in the review, some users have experienced issues with the quality of included components, such as gaskets or sensors. It's advisable to inspect all parts upon arrival and consider using higher-quality aftermarket gaskets if the supplied ones appear subpar.
• Sensor Malfunctions: Faulty sensors, like a TPS or distributor, can prevent the system from functioning correctly. Thoroughly testing existing sensors or opting for new, reputable replacements can mitigate this risk.
• Fuel System Compatibility: Ensuring your entire fuel system can support the demands of EFI is paramount. Insufficient fuel pressure or flow can lead to poor performance or engine damage.
• Throttle Body Sticking: A sticky throttle body can be a dangerous issue, leading to unintended acceleration. Ensure the throttle plates move freely and the linkage is properly adjusted.
• Installation Complexity: While FiTech aims for simplicity, the electrical and fuel system aspects of the conversion can be more complex than a simple carburettor swap. Thoroughly reading the installation manual and understanding your vehicle's existing wiring and fuel lines is essential.

Addressing the "Not Quite as Good as it Looks" Review

The negative review regarding a FiTech system is a stark reminder that even seemingly straightforward upgrades can present challenges. The customer experienced issues with distributors, TPS sensors, and pressure regulators, ultimately returning the system. They also noted poor-quality gaskets and a sticking throttle body. It's important to note that while this is one user's experience, it highlights areas where meticulous attention to detail during installation and component verification is crucial.

Key Takeaways from the Review:

• Don't Assume "Plug and Play": While FiTech aims for ease of installation, be prepared for potential troubleshooting.
• Inspect All Components: Pay close attention to the quality of included parts, especially gaskets.
• Test and Verify: Ensure all sensors and mechanical components are functioning correctly before and after installation.
• Factor in Additional Costs: Be prepared to purchase replacement parts if initial components are faulty or of poor quality.

Tips for a Successful FiTech Conversion

To increase your chances of a smooth and successful conversion, consider these tips:

1. Research Thoroughly: Before purchasing, identify the specific FiTech system that best suits your engine and performance goals. Read reviews, watch installation videos, and understand the system's requirements.

2. Plan Your Fuel System: Don't underestimate the importance of a robust fuel system. Decide whether an in-tank or external fuel pump is best for your application and ensure your fuel lines are appropriately sized and in good condition.

3. Inspect and Prepare Components: Upon receiving your FiTech kit, lay out all the parts and inspect them carefully. Clean any new components, and if the included gaskets look questionable, consider purchasing high-quality aftermarket replacements from a reputable supplier.

4. Follow Instructions Meticulously: Read the FiTech installation manual from cover to cover. If anything is unclear, contact FiTech support or consult online forums and communities for advice.

5. Prioritise Sensor Health: If you're retaining your existing distributor, ensure it's in excellent condition. If your kit includes a new distributor, install it carefully according to instructions. Test your TPS and other sensors if possible.

6. Address Throttle Linkage: Ensure the throttle linkage operates smoothly and without binding. Adjust it to provide a clean connection to the FiTech throttle body.

7. Start Simple with Tuning: Most FiTech systems have a self-learning capability. Start with the base settings provided in the manual and allow the system to learn as you drive. Avoid making drastic tuning adjustments too early.

8. Be Patient: EFI conversions can be a learning process. If you encounter issues, don't get discouraged. Troubleshooting is a normal part of automotive work.

Common Small Block Chevy Setups and EFI Considerations

The vast majority of small block Chevys, from the original 283ci to the popular 350ci and the stroker 383ci, can be converted to EFI. The core principles remain the same, but here are a few considerations for specific setups:

Important Note: Always verify the bolt pattern of your intake manifold to ensure compatibility with the FiTech throttle body. Most small block Chevys use a Square Flange or Holley 4150/4160 pattern, which FiTech systems are designed to accommodate.

Frequently Asked Questions (FAQs)

Q1: Can I use my existing fuel pump with a FiTech system?

A1: It depends on the type and condition of your existing fuel pump. Carburettors typically operate at very low fuel pressures (around 4-7 PSI), while most EFI systems require higher and more consistent pressures (typically 40-60 PSI). You will likely need to upgrade your fuel pump to an electric unit designed for EFI.

Q2: Will I need a new distributor?

A2: Some FiTech kits include a new distributor for optimal timing control. If you retain your existing points or electronic distributor, ensure it is in good working order and compatible with the EFI system's timing input. An HEI distributor is often a good choice.

Q3: How complex is the wiring?

A3: FiTech systems are designed with relatively straightforward wiring harnesses. They typically require a 12V switched power source, a good ground, and connections to sensors like the TPS and MAP sensor. If you are comfortable with basic automotive electrical work, it's usually manageable. If not, consider seeking professional help.

Q4: What if my intake manifold has a spread bore pattern?

A4: FiTech offers throttle bodies with both Square Flange and Spread Bore patterns. Ensure you select the correct throttle body to match your intake manifold. Adapters are also available but can sometimes introduce their own issues.

Q5: My FiTech system isn't running right. What should I check first?

A5: Start with the basics: fuel pressure, electrical connections, and sensor readings. Ensure the throttle body is clean and the throttle plates are not sticking. Check for vacuum leaks. Consult the FiTech troubleshooting guide and online forums for common issues and solutions.

Conclusion

Converting a carbureted small block Chevy to a FiTech EFI system can be a rewarding upgrade, offering significant improvements in performance and drivability. While the promise of a simple bolt-on solution is attractive, it's essential to approach the project with realistic expectations and a thorough understanding of the process. By carefully planning your fuel system, inspecting components, following instructions diligently, and being prepared to troubleshoot, you can overcome potential challenges and enjoy the benefits of modern fuel injection on your classic V8. Remember, a little extra care and attention during the installation can save a lot of headaches down the line.

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