How to replace the fuel pump

Every vehicle is equipped with a fuel gauge that tells the driver how much fuel is left in the fuel tank. The fuel pump is the device that creates the flow to deliver fuel from the fuel tank to the fuel rail.

The fuel pump is located in the fuel tank and attached to the fuel gauge sensor. The pump has gears or a rotor inside to create a flow that pushes fuel through the fuel lines. The fuel pump usually has a screen to protect it from large particles. Most pumps today have filters to filter out fine particles.

The fuel pump on older cars before fuel injection was introduced to the automotive industry was mounted on the side of the engines. These pumps worked like water cannons, pushing up and down to create flow. The fuel pump had a rod that was pushed by the camshaft cam. It doesn't matter if the camshaft was out of sync or not.

Some older cars broke the cam on the camshaft, causing the fuel pump to fail. Well, a quick fix for fueling the fuel management system was to use a 12 volt electric fuel pump. This electronic fuel pump is good, but it can create too much flow for the volume of fuel in the lines.

Symptoms of a malfunction of the gasoline pump

Because fuel is constantly being poured into the pump, drained when the engine is running, and sprayed out due to driving conditions, the fuel pump constantly heats up and cools down, causing the engine to burn slightly. Over time, the motor will burn out so much that it will cause too much resistance in the electrical contacts. This will cause the engine to stop working.

When the fuel is low all the time, the fuel pumps tend to run at a higher temperature, causing the contacts to burn. This will also cause the engine to stop working.

With the fuel pump running, listen for unusual sounds and high-pitched whining sounds. This could be a sign of worn gears inside the pump.

When driving a vehicle during a test drive, the throttle body of the engine strongly requires more fuel from the fuel management system. If the fuel pump is running, the engine accelerates quickly; however, if the fuel pump fails or fails, the engine will stumble and act like it wants to shut down.

• A warning: Do not use starting fluid to start an engine with a defective fuel pump. This will damage the engine.

Another cause of fuel pump failure is the type of fuel poured into the fuel tank. If fuel was filled at a gas station when the gas station fills the station, the debris at the bottom of the large storage tanks will rise up and enter the car's fuel tank. Particles can get inside the fuel pump and increase resistance when the rotor or gears begin to rub.

If fuel was filled at a gas station with very little traffic to the gas station, there may be excessive water in the fuel, causing the gears or fuel pump rotor to corrode and increase or seize the motor.

Also, if any of the wiring from the battery or computer to the fuel pump gets corroded, it will cause more resistance than normal and the fuel pump will stop working.

Fuel Gauge Sensor Malfunction on Computer Controlled Vehicles

If the fuel pump fails, the engine management system will record this event. The fuel pressure sensor will tell the computer if the fuel pressure has decreased by more than five pounds per square inch (psi).

Engine Light Codes Related to Fuel Level Sensor

• P0087
• P0088
• P0093
• P0094
• P0170
• P0171
• P0173
• P0174
• P0460
• P0461
• P0462
• P0463
• P0464

Part 1 of 9: Checking the condition of the fuel pump

Because the fuel pump is inside the fuel tank, it cannot be checked. However, you can check the electronic plug on the fuel pump for damage. If you have a digital ohmmeter, you can check for power at the harness plug. You can check the resistance of the motor through the plug on the fuel pump. If there is resistance, but not high, then the electric motor is working. If there is no resistance at the fuel pump, then the motor contacts are burnt.

Step 1: Check the fuel gauge to see the level. Document the pointer position or percentage of fuel level.

Step 2: start the engine. Listen for any problems in the fuel system. Check how long the engine is cranking. Check for a rotten egg smell as the engine is running lean.

• Attention: The smell of rotten eggs is due to overheating of the catalyst due to the combustion of exhaust gases above the temperature of the pyrometer.

Part 2 of 9: Preparing to replace the fuel pump

Having all the necessary tools and materials in place before starting work will allow you to get the job done more efficiently.

Necessary materials

• Hex key set
• socket wrenches
• Switch
• buffer pad
• combustible gas detector
• 90 degree grinder
• Drip tray
• Flash
• Flat head screwdriver
• Jack
• Fuel resistant gloves
• Fuel transfer tank with pump
• Jack stands
• needle nose pliers
• Protective clothing
• Safety glasses
• Sandpaper with soft grit
• Ratchet with metric and standard sockets
• RTV silicone
• Torque bit set
• Wrench
• Transmission jack or similar type (large enough to support the fuel tank)
• Wheel chocks

Step 1: Park your vehicle on a level, firm surface.. Make sure the transmission is in park (for automatic transmission) or in first gear (for manual transmission).

Step 2: Install wheel chocks around the rear wheels, which will remain on the ground.. In this case, the wheel chocks will be located around the front wheels, since the rear of the car will be raised. Apply the parking brake to block the rear wheels from moving.

Step 3: Install a nine volt battery in the cigarette lighter.. This will keep your computer running and save the current settings in the car. If you don't have a nine-volt battery, no big deal.

Step 4: Open the car hood to disconnect the battery.. Remove the ground cable from the negative battery terminal by turning off power to the fuel pump and transmitter.

Step 5: Raise the car. Using a jack recommended for the weight of the vehicle, raise it under the vehicle at the indicated jack points until the wheels are completely off the ground.

Step 6: Install Jacks. The jack stands should be located under the jacking points. Then lower the car onto the jacks. For most modern cars, the jack stand attachment points are on a weld right under the doors along the bottom of the car.

• Attention. Follow the instructions for use to determine the correct location for the jack**.

Part 3 of 9: Remove the fuel pump

Removing the fuel pump from cars with an injection engine

Step 1: Open the fuel tank door to access the filler neck.. Remove the mounting screws or bolts attached to the cutout. Remove the fuel cap cable from the fuel filler neck and set aside.

Step 2: Get your vine and tools to work. Go under the car and find the fuel tank.

Step 3: Take a transmission jack or similar jack and place it under the fuel tank.. Loosen and remove the fuel tank straps. Lower the fuel tank slightly.

Step 4 Reach for the top of the fuel tank.. You will need to feel for the harness attached to the tank. This is the fuel pump harness or the transmission unit on older vehicles. Disconnect the harness from the connector.

Step 5: Lower the fuel tank even lower to get to the vent hose attached to the fuel tank.. Remove the clamp and small vent hose to provide more clearance.

• Attention: Vehicles made in 1996 or later will have a carbon return fuel filter attached to the vent hose to collect fuel vapor for emissions.

Step 6: Remove the clamp from the rubber hose securing the fuel filler neck.. Rotate the fuel filler neck and pull it out of the rubber hose. Pull the fuel filler neck out of the area and remove it from the vehicle.

Step 7: Remove the fuel tank from the car. Before removing the fuel tank, be sure to drain the fuel from the tank.

When removing the filler neck, it is best to have the car with 1/4 tank of fuel or less.

Step 8: After removing the fuel tank from the vehicle, inspect the rubber hose for cracks.. If there are cracks, the rubber hose must be replaced.

Step 9: Clean the wiring harness on the vehicle and the fuel pump connector on the fuel tank.. Use an electric cleaner and a lint-free cloth to remove moisture and debris.

When the fuel tank is removed from the vehicle, it is recommended to remove and replace the one-way breather on the tank.

If the breather on the fuel tank is faulty, you will need to use a pump to check the condition of the valves. If the valve fails, the fuel tank must be replaced.

The breather valve on the fuel tank allows fuel vapor to escape into the canister, but prevents water or debris from entering the tank.

Step 10: Clean up dirt and debris around the fuel pump.. Turn out bolts of fastening of the fuel pump. You may need to use hex wrenches with torque to loosen the bolts. Wear goggles and remove the fuel pump from the fuel tank. Remove the rubber seal from the fuel tank.

• Attention: You may need to turn the fuel pump to get the float attached to it out of the fuel tank.

Part 4 of 9: Remove the fuel pump from the carbureted engines.

Step 1: Locate a damaged or defective fuel pump.. Remove the clamps that secure the fuel hose to the supply and delivery ports.

Step 2: Place a small pan under the fuel hose.. Disconnect the hoses from the fuel pump.

Step 3: Remove the fuel pump mounting bolts.. Remove the fuel pump from the cylinder block. Pull the fuel rod out of the cylinder block.

Step 4: Remove the old gasket from the cylinder block where the fuel pump is installed.. Clean the surface with fine sandpaper or a buffer disc on a 90 degree grinder. Remove any debris with a clean, lint-free cloth.

Part 5 of 9: Install the new fuel pump

Installing a fuel pump on cars with an injection engine

Step 1: Install a new rubber gasket on the fuel tank.. Install the fuel pump with a new float in the fuel tank. Install the fuel pump mounting bolts. Tighten the bolts by hand, then 1/8 turn more.

Step 2: Place the fuel tank back under the car.. Wipe the rubber fuel tank hose with a lint-free cloth**. Install a new clamp on the rubber hose. Take the filler neck of the fuel tank and screw it into the rubber hose. Reinstall the clamp and tighten the slack. Allow the fuel filler neck to rotate, but do not allow the collar to move.

Step 3: Lift the fuel tank up to the vent hose.. Secure the ventilation hose with a new clamp. Tighten the clamp until the hose is twisted and turns 1/8 turn.

• A warning: Make sure you don't use old clips. They will not hold tight and will cause steam to leak.

Step 4: Raise the fuel tank all the way to align the fuel filler neck with the cutout.. Align the fuel filler neck mounting holes. Lower the fuel tank and tighten the clamp. Make sure the fuel filler neck does not move.

Step 5: Raise the fuel tank to the wiring harness.. Connect the fuel pump or transmitter harness to the fuel tank connector.

Step 6: Attach the fuel tank straps and tighten them all the way.. Tighten the mounting nuts to specifications on the fuel tank using a torque wrench. If you don't know the torque value, you can tighten the nuts an additional 1/8 turn with blue loctite.

Step 7: Align the fuel filler neck with the cutout in the fuel door area.. Install the mounting screws or bolts in the neck and tighten it. Connect the fuel cap cable to the filler neck. Screw the fuel cap on until it locks into place.

Part 6 of 9: Installing the Fuel Pump on Carburetor Engines

Step 1: Apply a small amount of RTV silicone to the engine block where the gasket came off.. Let stand for about five minutes and put on a new gasket.

Step 2: Install the new fuel rod in the cylinder block.. Place the fuel pump on the gasket and install the mounting bolts with RTV silicone on the threads. Tighten the bolts by hand, then 1/8 turn more.

• Attention: RTV silicone on bolt threads prevents oil leakage.

Step 3: Install new fuel hose clamps.. Connect the fuel hoses to the fuel supply and delivery ports of the fuel pump. Tighten the clamps firmly.

Part 7 of 9: Leak Check

Step 1: Open the car hood. Reconnect the ground cable to the negative battery post.

Remove the nine volt fuse from the cigarette lighter.

Step 2: Tighten the battery clamp firmly to ensure a good connection..

• AttentionA: If you didn't have a XNUMX-volt power saver, you'll have to reset all of your car's settings, such as the radio, power seats, and power mirrors. If you had a nine volt battery, you will need to clear the engine codes, if any, before starting the car.

Step 3: turn on the ignition. Listen for the fuel pump to turn on. Switch off the ignition after the fuel pump stops making noise.

• AttentionA: You will need to turn the ignition key on and off 3-4 times to make sure the entire fuel rail is filled with fuel.

Step 4: Use a combustible gas detector and check all connections for leaks.. Smell the air for the smell of fuel.

Part 8 of 9: Lower the car

Step 1: Gather all the tools and creepers and get them out of the way..

Step 2: Raise the car. Using a jack recommended for the weight of the vehicle, raise it under the vehicle at the indicated jack points until the wheels are completely off the ground.

Step 3: Remove the jack stands and keep them away from the vehicle..

Step 4: Lower the car so that all four wheels are on the ground.. Pull out the jack and set it aside.

Step 5: Remove the wheel chocks from the rear wheels and set them aside..

Part 9 of 9: Test drive the car

Step 1: Drive the car around the block. While checking, listen for unusual noise from the fuel pump. Also, accelerate the engine quickly to make sure the fuel pump is working properly.

Step 2: Watch the fuel level on the dashboard and check for the engine light to come on..

If the engine light comes on after replacing the fuel pump, this may indicate further diagnosis of the fuel pump assembly or a possible electrical problem in the fuel system.

If the problem persists, you should seek the assistance of one of our certified mechanics who can inspect the fuel pump and diagnose the problem.