1967 Mustang Fuel Pump: Complete Guide to Replacement, Symptoms, and Best Options

The bottom line: If your 1967 Ford Mustang is experiencing hard starting, sputtering at high speeds, stalling, or a whining noise from the fuel tank area, the fuel pump is likely failing. The 1967 Mustang came with either a mechanical fuel pump mounted on the engine block (for V8 models like the 289, 390, and 428 cubic inch engines) or a mechanical pump for the 6-cylinder engines. Replacing the fuel pump is a straightforward DIY job that can restore proper fuel delivery and get your classic Mustang running smoothly again.

Understanding Your 1967 Mustang Fuel Pump

The 1967 Mustang was equipped with a mechanical fuel pump, which is a simple, reliable component that uses a lever actuated by an eccentric on the camshaft to pump fuel from the tank to the carburetor. These pumps are mounted on the side of the engine block and are driven by the engine's rotation.

Key facts about the 1967 Mustang fuel pump:

  1. Engine-specific fitment: The fuel pump varies by engine size. For the 1967 Mustang, common engines include the 200 cubic inch 6-cylinder, the 289 cubic inch V8, the 390 cubic inch V8, and the 428 cubic inch V8. Each requires a specific pump with the correct inlet and outlet positions, pressure rating, and flow rate.

  2. Pressure and flow specifications: A typical mechanical fuel pump for a 1967 Mustang delivers between 5.5 and 7 PSI of pressure and flows around 25 to 40 gallons per hour (GPH). The Carter M6588 mechanical pump, for example, provides 7 PSI and 25 GPH.

  3. Integral filter canister: Many 1967 Mustang V8 fuel pumps include an integral filter canister, which houses a replaceable fuel filter element. This design simplifies maintenance by combining the pump and filter into one unit.

Common Symptoms of a Failing Fuel Pump

If your 1967 Mustang's fuel pump is going bad, you'll notice several telltale signs. Catching these early can prevent being stranded and avoid damage to other fuel system components.

Symptom 1: Engine sputters or hesitates at high speeds. When the fuel pump cannot deliver enough fuel to meet the engine's demand, the engine will sputter, hesitate, or lose power, especially under load or at high RPM.

Symptom 2: Hard starting or no-start condition. A weak fuel pump may not provide enough fuel pressure to fill the carburetor bowl, making the engine difficult to start. In severe cases, the engine will crank but not fire.

Symptom 3: Engine stalls unexpectedly. If the fuel pump fails completely while driving, the engine will stall and may not restart until the pump cools down or is replaced.

Symptom 4: Whining noise from the fuel tank area. A failing fuel pump may produce a loud whining or humming sound. While this is more common with electric pumps, mechanical pumps can also make noise if the bearings or diaphragm are worn.

Symptom 5: Poor fuel economy and engine misfires. A fuel pump that delivers inconsistent pressure can cause the engine to run rich or lean, leading to reduced fuel economy, misfires, and rough idling.

How to Diagnose a Bad Fuel Pump

Before you start replacing parts, it's important to confirm the fuel pump is the actual problem. Here's a simple diagnostic process:

Step 1: Check for fuel delivery. Disconnect the fuel line at the carburetor and crank the engine briefly. If fuel does not spray out, the pump may be faulty. Be careful of fuel spray and work in a well-ventilated area.

Step 2: Check fuel pressure. Use a fuel pressure gauge to measure the pressure at the carburetor inlet. For a 1967 Mustang, the pressure should be between 5.5 and 7 PSI. If the pressure is low or zero, the pump is likely bad.

Step 3: Inspect for leaks. Look for fuel leaks around the pump mounting surface, the fuel line connections, and the pump body. A leaking diaphragm will often cause fuel to drip from the pump's vent hole.

Step 4: Check the fuel filter. A clogged fuel filter can mimic a bad fuel pump, causing similar symptoms. Replace the fuel filter first if it hasn't been changed recently.

Replacement Guide: How to Replace a 1967 Mustang Fuel Pump

Replacing the fuel pump on a 1967 Mustang is a job that most DIYers can handle with basic hand tools. The process takes about one to two hours.

Tools and parts you'll need:

  • Ratchet set with extensions and a universal joint (for hard-to-reach bolts)
  • Tubing or open-end wrenches (for fuel line fittings)
  • Screwdriver or hose clamp pliers
  • Bolt or wooden dowel to plug the fuel line from the tank
  • New fuel pump with gasket
  • New fuel filter
  • Gasket sealer
  • Safety glasses and gloves

Step-by-step installation:

1. Disconnect the battery. Always disconnect the negative battery cable to prevent any electrical sparks when working near fuel.

2. Relieve fuel system pressure. For a mechanical pump, this is less critical than with electric pumps, but it's still wise to remove the fuel cap and let the system depressurize.

3. Disconnect the fuel lines. Use a wrench to hold the fuel pump fitting and another wrench to loosen the line nut. Disconnect the fuel inlet hose from the tank and the outlet line to the carburetor. Immediately plug the fuel tank hose with a bolt or dowel to prevent fuel from draining out.

4. Remove the old fuel pump. Unbolt the two mounting bolts that hold the pump to the engine block. Gently pull the pump away from the engine. The pump lever will slide out of the engine. Remove the old gasket and clean the mounting surface thoroughly. Do not let gasket residue fall into the engine opening.

5. Install the new fuel pump. Apply gasket sealer to both sides of the new gasket, then slide it over the mounting bolts on the new pump. Apply a small dab of grease to the tip of the pump lever where it contacts the camshaft eccentric. Carefully position the pump so the lever aligns with the camshaft lobe, then bolt it in place. Tighten the bolts evenly to the torque specified in your shop manual.

6. Reconnect the fuel lines. Reattach the fuel inlet hose from the tank and the outlet line to the carburetor. Tighten the fittings securely, but do not overtighten. It is recommended to use a small amount of gasoline-proof gasket sealer on the threads to prevent leaks.

7. Replace the fuel filter. If your pump has an integral filter canister, install a new filter element. If the filter is inline, replace it as well.

8. Test for leaks. Reconnect the battery, start the engine, and let it run. Check all connections, the pump mounting surface, and the fuel lines for any signs of leakage. If you see any leaks, shut the engine off immediately and tighten the connections.

Choosing the Right Fuel Pump for Your 1967 Mustang

When selecting a replacement fuel pump, you have several options. The most important factor is matching the pump to your specific engine and fuel system requirements.

For 1967 Mustang V8 engines (289, 390, 428):

  • Carter M6588 mechanical fuel pump: This is a popular choice for small-block Ford engines (289, 302, 351 Windsor). It delivers 7 PSI and 25 GPH, and it includes a gasket. It fits 1966-1973 Mustangs with 289/302/351 Windsor engines.

  • Reproduction fuel pump with integral filter canister: For the 390 V8, a reproduction pump with an integral filter canister is available. It features a high-volume design (40 GPH), OE appearance, and factory-tested reliability. It fits 1967 Mustang 390 V8 models.

  • NOS (New Old Stock) fuel pump: Original Airtex parts are still available for 1967 Mustangs with 390, 410, and 428 cubic inch engines. These are genuine original parts, often still in their original packaging with gaskets.

For 1967 Mustang 6-cylinder engines (200 cubic inch):

  • Mechanical fuel pump for 6-cylinder engines: These pumps are different from the V8 versions. They are designed for the 200 cubic inch 6-cylinder engine and deliver 5.5 PSI. They fit 1965-1972 Ford and Mercury 6-cylinder models.

For performance upgrades (EFI conversions):

  • Holley EFI fuel tank module: If you are converting your 1967 Mustang to electronic fuel injection, you need an in-tank electric pump. The Holley 12-305 module fits 1964-1970 Mustangs and flows 255 LPH, supporting up to 550 horsepower. It includes a HydraMat filter and an internal regulator set to 58 PSI.

  • FiTech inline frame mount fuel delivery kit: This external pump kit delivers 255 LPH and supports up to 600-625 horsepower. It includes pre and post filters, hose ends, and 25 feet of EFI-rated hose. It mounts along the frame rail.

Recommended Product: KEMSO Fuel Pump

When it comes to reliable, high-performance fuel pumps for your 1967 Mustang, KEMSO Racing offers an excellent solution. KEMSO fuel pumps are designed as OEM replacement parts, meaning they match the original specifications for fitment, pressure, and flow. What sets KEMSO apart is their commitment to quality and durability.

Why choose KEMSO?

  1. High-performance design: Every KEMSO fuel pump is built to deliver consistent fuel pressure and flow, ensuring your engine gets the fuel it needs under all driving conditions.

  2. OEM replacement quality: KEMSO pumps are manufactured to meet or exceed original equipment standards. They feature the correct inlet and outlet positions, proper diameter and length, and application-specific pressure and flow specifications.

  3. Lifetime warranty: KEMSO backs every fuel pump with a lifetime warranty. This means you can install their pump with confidence, knowing that if any issues arise, KEMSO will stand behind their product.

  4. Broad application coverage: While KEMSO offers pumps for a wide range of vehicles, their focus on quality and performance makes them a trusted choice for classic car owners who want a reliable fuel delivery system.

Visit KEMSO Racing today: KEMSO Racing Fuel Pump Collection

Frequently Asked Questions

Q: How long does a mechanical fuel pump last on a 1967 Mustang?
A: A mechanical fuel pump can last 50,000 to 100,000 miles or more, depending on driving conditions, fuel quality, and maintenance. However, ethanol-blended fuels can degrade the rubber diaphragm over time, shortening the pump's lifespan.

Q: Can I use an electric fuel pump instead of a mechanical one?
A: Yes, but it requires modifications. An electric pump needs to be mounted near the fuel tank, and you'll need to install a pressure regulator to reduce the pressure to 5-7 PSI for a carbureted engine. For EFI conversions, an in-tank module like the Holley 12-305 is the best option.

Q: Should I replace the fuel filter when changing the fuel pump?
A: Absolutely. Always replace the fuel filter when you change the fuel pump. A clogged filter can cause the new pump to work harder and fail prematurely. If the old filter is plugged, you may also need to drain and clean the fuel tank.

Q: What causes a fuel pump to fail?
A: Common causes include age-related wear of the diaphragm, contamination from debris in the fuel tank, running the tank low on fuel (which allows sediment to reach the pump), and degradation of rubber components from ethanol-blended fuels.

Q: Do I need to prime a new mechanical fuel pump?
A: Mechanical fuel pumps are self-priming. Once you install the pump and crank the engine, the pump will pull fuel from the tank and fill the carburetor bowl. However, if the carburetor is completely dry, it may take a few seconds of cranking to get fuel flowing.

Final Thoughts

Replacing the fuel pump on your 1967 Mustang is a straightforward repair that can solve many common driveability issues. By understanding the symptoms of a failing pump, following the proper diagnostic steps, and selecting the right replacement part, you can get your classic Mustang back on the road with confidence.

For the best combination of quality, performance, and peace of mind, consider a KEMSO fuel pump for your 1967 Mustang. Their OEM replacement design, high-performance construction, and lifetime warranty make them a smart choice for any classic car owner.

Visit KEMSO Racing at https://www.kemsoracing.com/ to find the perfect fuel pump for your 1967 Mustang. Their team is dedicated to helping you fuel your adventure with confidence.


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