1999 Ford Windstar Fuel Pump: A Complete Replacement Guide

Replacing the failing fuel pump in your 1999 Ford Windstar is a critical repair necessary to restore engine performance and drivability. While demanding due to the fuel tank location, the task is achievable for a prepared DIY mechanic using common tools and proper safety procedures. This comprehensive guide details every step, from recognizing failure symptoms to installation, testing, and preventive maintenance.

Understanding Fuel Pump Failure in the 1999 Ford Windstar

The fuel pump is the heart of your Windstar's fuel delivery system. Located inside the fuel tank, its primary function is to draw fuel from the tank and deliver it under consistent high pressure to the fuel injectors. A failing pump disrupts this vital process.

Several factors cause 1999 Windstar fuel pump failure:

• Normal Wear and Tear: Like any electromechanical component, the pump's motor and internal parts wear out over time and mileage. Pumps often last 100,000+ miles, but many 1999 models are well beyond this point.
• Fuel Contamination: Dirt, rust, or debris entering the tank can accelerate pump wear. Running the tank extremely low regularly forces the pump to work harder and can lead to overheating.
• Electrical Issues: Voltage spikes, corroded wiring connectors, or failing relays can damage the pump motor. Constant exposure to fuel makes internal electrical components vulnerable.
• Clogged Fuel Filter: While the Windstar has a separate in-line fuel filter, severe clogging creates excessive backpressure, forcing the pump to work harder and potentially overheat.

Recognizing Symptoms of a Bad Fuel Pump

Diagnosing fuel pump failure early prevents roadside breakdowns. Look for these signs specific to the 1999 Windstar:

• Engine Cranks But Won't Start: This is the most common symptom. If you hear the starter turning the engine normally, but the engine doesn't fire, lack of fuel delivery is a prime suspect.
• Sputtering or Hesitation Under Load: As you accelerate, especially going uphill or with a full load, the engine may sputter, surge, or lose power dramatically. This indicates the pump cannot maintain sufficient fuel pressure during high demand.
• Loss of Power While Driving: The engine may suddenly lose power and stall, potentially restarting after sitting for a few minutes (allowing a hot pump to cool slightly).
• Whining Noise from the Fuel Tank: An excessively loud, high-pitched whine or buzzing sound emanating from the area under the rear seats (where the tank is located) signals a struggling pump nearing the end of its life. New pumps are quieter but not silent.
• Difficult Hot Starts: The pump may crank the engine longer than usual or fail to start immediately after the engine is warm. When shut down, heat from the engine and exhaust can affect an already weak pump within the tank.
• Check Engine Light: While not specific, a failing pump can trigger fuel pressure-related diagnostic trouble codes (DTCs) like P0171 (System Too Lean Bank 1), P0087 (Fuel Rail/System Pressure Too Low), or P0230 (Fuel Pump Primary Circuit Malfunction). Retrieving these codes with an OBD-II scanner is essential diagnostics.
• Vehicle Diesels After Shutoff: Rough running or "dieseling" for a few seconds after turning the ignition off can indicate leaking fuel injectors, but can also be related to residual pressure issues stemming from the pump or pressure regulator.

Confirming the Diagnosis is Essential

Don't replace the pump based solely on symptoms. Confirm fuel pressure failure:

1. Locate the Schrader Valve: The 1999 Windstar has a tire valve-like test port on the fuel rail at the front of the engine.
2. Use a Fuel Pressure Gauge: Rent or buy a gauge designed for fuel injection pressure testing. Connect it securely to the Schrader valve.
3. Turn Key to "ON": Do not start the engine. Observe the pressure reading. It should rapidly jump to between 30-45 PSI and hold steady or drop only very slowly (over minutes). Consult your Windstar manual for the exact specification.
4. Check Running Pressure: Start the engine. Pressure should remain stable within spec at idle.
5. Check Pressure Under Load: Pinch the fuel return line briefly (using appropriate clamps – be cautious). Pressure should jump significantly. Key Finding: Low pressure on initial prime, pressure that bleeds down too fast, or failure to build sufficient pressure under load confirms a fuel delivery fault – pump, filter, or pressure regulator.

Essential Tools and Safety Preparation

Gathering the right tools ensures efficiency and safety:

• Safety Gear: Chemical-resistant gloves, ANSI-approved safety glasses, long sleeves, shop rags. NO sparks, flames, or smoking.
• Vehicle Support: High-quality jack stands rated for the vehicle weight. Do NOT work under a vehicle supported only by a jack.
• Floor Jack: A hydraulic floor jack makes lowering the tank significantly easier and safer.
• Hand Tools: Basic socket set (metric – includes 8mm, 10mm, 13mm, 15mm, 18mm sockets commonly), ratchet, extensions (long), box wrenches, screwdrivers (flathead and Phillips), pliers, hose clamp pliers.
• Specialized Tools: Torx bit set (often needed for pump module lock ring), fuel line disconnect tools (size appropriate for Windstar lines – typically 5/16" and 3/8" quick-connect fittings at the tank), fuel pressure gauge.
• Workspace: Well-ventilated area away from ignition sources. Have a Class B fire extinguisher readily accessible.
• New Parts: New fuel pump module assembly (highly recommended over just the pump), new fuel filter. Genuine Motorcraft or a reputable aftermarket brand (Airtex, Delphi, Bosch) are best. Verify part numbers carefully.
• Optional but Helpful: Penetrating oil (for rusty bolts), brake cleaner (non-chlorinated, for general cleaning), marker pen, drain pan large enough to capture residual fuel.

Fuel System Depressurization is Mandatory

Failure to do this can result in a dangerous spray of pressurized gasoline.

1. Locate the Fuel Pump Relay: Find the Power Distribution Box under the hood. Identify the F/P (Fuel Pump) relay using the diagram on the box lid. On the 1999 Windstar, it's usually the blue relay labeled #10 in the top row.
2. Run Down Pressure: Start the engine. Pull the F/P relay while the engine is running. The engine will stall within a few seconds as fuel pressure depletes.
3. Crank Engine: Attempt to start the engine for 3-5 seconds to purge any residual pressure. The engine should not start.
4. Remove Relay: Pull the relay out completely and set it aside. Some also disconnect the inertia fuel shut-off switch located behind the passenger side kick panel as an extra precaution.
5. Relieve Pressure at Schrader Valve: Place rags over the fuel rail Schrader valve. Carefully depress the valve core to release any remaining fuel pressure slowly. Catch fuel in a small container.

Step-by-Step Removal of the 1999 Windstar Fuel Tank

This is the most labor-intensive part. The tank is located under the vehicle between the rear axle and the bumper.

1. Disconnect Battery: Disconnect the NEGATIVE battery terminal to prevent electrical shorts and sparks.
2. Drain/Remove Fuel: Use a hand-operated fluid transfer pump to drain as much fuel as possible from the tank through the filler neck into an approved gasoline container. Draining significantly reduces weight and spill risk. Alternative: Syphon carefully or run the tank very low before starting.
3. Remove Spare Tire: Improves access to the tank area.
4. Detach Fuel Filler Neck: Open the fuel filler door. Inside the fender well, loosen the large hose clamp securing the filler neck hose to the tank. Carefully twist and pull the neck away from the tank.
5. Disconnect Evaporative (EVAP) Lines: Locate the vapor lines running near the filler neck to the charcoal canister. Squeeze the locking tabs and disconnect these lines.
6. Disconnect Electrical Connector: Find the wiring harness connector going to the fuel pump module atop the tank. Press the release tab(s) firmly and disconnect it.
7. Disconnect Fuel Lines: Locate the supply and return metal fuel lines at the front of the tank. Use the correct size quick-connect tool inserted between the plastic line collar and the metal line fitting. Push the tool in firmly, then pull the plastic line off the fitting. Be prepared for minor residual fuel spillage. Cover the open lines.
8. Support Tank with Floor Jack: Position the floor jack centered under the fuel tank with a broad, flat piece of wood on the jack pad to distribute the load evenly.
9. Remove Tank Strap Bolts: Identify the three metal straps holding the tank – two near the rear differential, one near the front. Spray the bolts liberally with penetrating oil and wait. Carefully remove the front strap bolt first. Then remove the two rear strap bolts. Keep the straps and bolts organized.
10. Slowly Lower the Tank: Carefully lower the jack slowly. The tank will start to descend. Crucial: Watch for any hidden wires or hoses still connected and disconnect them. Lower the tank only as far as necessary to gain access to the pump module on top – about 6-10 inches typically suffices. Place wood blocks between the tank and the jack for extra safety if stopping at this point.

Replacing the Fuel Pump Module Inside the Tank

1. Clean Around the Module: Thoroughly clean dirt and debris from the top of the tank around the pump module access cover and lock ring.
2. Remove Lock Ring: Ford uses large plastic or metal lock rings securing the module. Use the appropriate tool (brass drift punch, large screwdriver, or specific lock ring tool) inserted into the locking tabs. Strike the tool counterclockwise firmly to break the ring loose, then unscrew it completely by hand. This requires significant force sometimes.
3. Remove Old Module Assembly: Carefully lift the entire fuel pump module assembly straight up and out of the tank. Tilt it slightly if needed to maneuver the fuel level float arm past the tank opening. Crucially: Note the orientation of the float arm and the module relative to the tank. The new module must be installed in the exact same position. Remove and discard the large O-ring seal around the opening.
4. Prepare New Module: Verify the new module matches the old one exactly. Remove any packaging covers/protectors from the inlet filter and outlets. DO NOT drop the new module or damage the float arm.
5. Install New O-Ring: Lightly lubricate the brand new O-ring supplied with the module assembly with clean engine oil or transmission fluid. Never use grease or petrolatum. Position it perfectly in the groove around the tank opening.
6. Install New Module: Carefully insert the new module assembly into the tank, aligning it exactly as the old one was oriented. Gently push it straight down until it seats fully in the opening. Ensure the float arm moves freely without binding.
7. Install Lock Ring: Thread the lock ring onto the tank collar by hand as much as possible, ensuring it engages the threads correctly. Then, using the appropriate tool, tap it firmly clockwise until it is completely seated and tight against the stops. This requires significant force – ensure it’s locked securely.

Reinstalling the Fuel Tank

This is largely the reverse of removal, but requires care:

1. Raise Tank: Slowly raise the jack to lift the tank back into position. Continuously check that no wires or hoses get pinched between the tank and the chassis.
2. Install Tank Straps: Align the tank straps into their original positions. Insert and start the strap bolts by hand. Apply a small amount of anti-seize compound to the threads if they were rusted. Tighten the bolts securely, ensuring the tank is held firmly but not distorted. Follow the recommended sequence: secure the front strap bolt first, then the two rear strap bolts.
3. Reconnect Fuel Lines: Push the supply and return metal lines back onto their respective quick-connect fittings atop the tank module. You should hear a distinct "click" as the locking collars engage. Pull firmly on each line to ensure it is locked.
4. Reconnect Electrical Connector: Reattach the main electrical connector to the pump module securely. Listen for a click.
5. Reconnect EVAP Lines: Reconnect the vapor lines to their fittings.
6. Reattach Filler Neck: Carefully reinsert the fuel filler neck into the tank opening and secure it with the large hose clamp. Ensure it's seated straight and tightened properly to prevent leaks or fumes.
7. Reinstall Spare Tire.
8. Lower Vehicle: Remove the jack stands and lower the vehicle to the ground.
9. Reconnect Battery: Reconnect the NEGATIVE battery terminal.

Priming, Testing, and Verifying the Repair

1. Reinstall Fuel Pump Relay: Place the F/P relay back into its socket in the Power Distribution Box.
2. Prime the System: Turn the ignition key to the "ON" position (do not start). You should hear the new pump whir for 1-2 seconds as it primes the system. Turn the key "OFF". Repeat the "ON" cycle 2-3 more times to build solid pressure. Listen for unusual sounds from the pump. A smooth, moderate whine is normal; loud buzzing or screeching is not.
3. Check for Leaks: Before starting, get under the vehicle and visually inspect all connection points around the tank: fuel lines (supply, return), filler neck, EVAP lines, electrical connector. Look for any drips or signs of fuel weeping. If you smell fuel or see ANY leak, STOP IMMEDIATELY – do not start the engine. Locate and fix the leak source first.
4. Start the Engine: Start the engine. It might crank slightly longer than usual the first time as air is purged from the lines. It should settle into a smooth idle.
5. Recheck for Leaks: With the engine running, perform another careful visual inspection for leaks around the tank connections. Also briefly rev the engine and watch.
6. Monitor Performance: Drive the vehicle. Pay attention to starting ease, idle quality, acceleration response, and any power loss symptoms. It should feel significantly improved. Listen for unusual pump noises.
7. Verify Fuel Pressure: If possible, retest fuel pressure using the Schrader valve to confirm it's within specification both at idle and under load (using the return line pinch test cautiously).

Long-Term Care: Preventing Premature Fuel Pump Failure

Extend the life of your new pump:

• Never Run Critically Low: Avoid letting the fuel level drop below 1/4 tank regularly. Keeping the pump submerged in fuel cools and lubricates it.
• Change the Fuel Filter: Replace the external in-line fuel filter every 30,000 miles as preventive maintenance. A clogged filter strains the pump.
• Use Quality Fuel: Purchase gasoline from reputable stations. Contaminants accelerate wear.
• Fix Electrical Issues Promptly: Address problems like weak batteries, alternator issues, or corroded battery terminals that can cause voltage irregularities affecting the pump.
• Maintain Tank Components: Inspect filler neck seals periodically. Ensure the gas cap is sealing correctly to maintain proper tank pressure.

When to Seek Professional Help

Replacing the fuel pump module requires significant time, physical effort, and careful attention to safety. Seek professional assistance if:

• You are uncomfortable working under the vehicle on critical components.
• Tank strap bolts are severely rusted and snap during removal.
• Fuel lines are corroded or fittings are damaged.
• After replacement, leaks persist or the vehicle still exhibits fuel delivery problems despite correct installation.
• Electrical troubleshooting is needed beyond basic connector checks.

Final Words

A failing fuel pump in your 1999 Ford Windstar creates major drivability issues. Replacing it demands meticulous preparation, adherence to critical safety protocols regarding fuel handling and vehicle support, and methodical execution of tank removal and pump module replacement. Using a complete module assembly, high-quality parts, and following these detailed steps provides a lasting solution. Taking preventive actions like maintaining sufficient fuel levels and timely filter changes will safeguard your investment and ensure reliable performance from your minivan for years to come. Successfully completing this repair restores essential engine operation and vehicle safety.