Ford Bronco F150 Fuel Injector Upgrade | 1985-1996 Bronco F Series | Gain MPG | Bronco Restoration

Introduction

This tutorial will guide you through the process of upgrading the fuel injectors on a 1990 Ford Bronco with a 5.8L V8 engine. By replacing the stock single-hole injectors with newer four-hole injectors from a 1997 Ford Explorer, you can improve fuel atomization, potentially gaining 1 to 2 miles per gallon (MPG) in fuel efficiency. This upgrade is applicable to many Ford vehicles from 1980 to 1996.

Step 1: Prepare for the Upgrade

• Disconnect the Battery: Start by removing the negative terminal from the battery to prevent electrical shorts.
• Remove Throttle Cover: Take off the throttle cover to gain access to the components underneath.
• Unclip Throttle Cable: Unsnap the throttle cable from its connection.
• Remove Throttle Bracket: Take off the throttle bracket and store the screws in their original holes to avoid losing them.

Step 2: Remove Components for Access

• Unbolt the EGR: Disconnect the EGR valve, keeping the bolt attached to maintain gasket placement; most gaskets can be reused.
• Unplug Electrical Connectors: Disconnect the IAC (Idle Air Control), purge valve, and any vacuum lines attached to the throttle body.
• Remove Throttle Body: Carefully set the throttle body aside to create more space.

Step 3: Remove the Intake Manifold

• Locate and Remove Bolts: There are six bolts holding the intake manifold in place. One of them is a T40 Torx located in the inner middle section, which can be tricky to access. Use a quarter-inch extension and socket to remove it first.
• Lift Off the Plenum: After removing the bolts, lift the intake manifold off. Be cautious of any remaining vacuum lines and electrical connectors.

Step 4: Access the Fuel Injectors

• Remove Fuel Lines: Use a fuel line removal tool to disconnect the fuel lines safely.
• Unplug Fuel Injectors: Gently pry off the old injectors from the fuel rail; use caution as they may be brittle.
• Remove Fuel Rail Bolts: Take out the four bolts securing the fuel rail and lift it with the injectors attached.

Step 5: Replace Injectors

• Compare Old and New Injectors: Examine the old injectors against the new four-hole injectors from the 1997 Explorer to see the difference in design.
• Prepare New Injectors: Lightly coat the seals of the new injectors with WD-40 to aid installation.
• Install New Injectors: Push the new injectors into the fuel rail until they are secure.

Step 6: Reassemble Components

• Reinstall Fuel Rail: Place the fuel rail back onto the engine, ensuring all injectors are seated correctly.
• Reconnect Fuel Lines: Attach the fuel lines and secure them properly.
• Reinstall Throttle Body: Clean the surface and install the throttle body with a new or good-condition gasket.
• Reconnect All Electrical Connectors: Ensure the IAC, purge solenoid, and throttle cable are plugged back in.

Step 7: Reattach Remaining Components

• Install Ground Strap: Don’t forget to reconnect the ground strap and any other brackets.
• Reinstall EGR Valve: Make sure the gasket is in place and secure the EGR.
• Final Checks: Reattach intake boots and throttle cover, and reconnect the battery.

Conclusion

Upgrading the fuel injectors on your 1990 Ford Bronco can enhance fuel efficiency and performance. By following these steps, you can successfully complete the installation and enjoy the benefits of better MPG and throttle response. For future maintenance, consider replacing other components like the PCV valve and hoses while you have the intake manifold removed. If you found this guide helpful, consider sharing or subscribing for more automotive upgrades and tips.