Replacing The Fuel Pump On A Porsche Boxter: Step-By-Step Guide

If you're looking to replace the fuel pump on your 2000 Porsche Boxter, you've come to the right place. This job should only be attempted by experienced mechanics or automotive enthusiasts as it can be dangerous due to the risk of fire.

First, you'll need to disconnect the battery to reduce the chance of a fire. Next, you'll need to drain the fuel tank and remove the fuel pump relay. With the cover off, you can then replace the pump and pre-pump filter screen. Once the new pump is installed, you'll need to reconnect the fuel lines and battery, and then check for any fuel leaks.

It's also recommended to replace the fuel filter at the same time as the fuel pump, as well as the intake screen for in-tank fuel pumps. Additionally, on some vehicles, the fuel pump relay is known to fail, so it's good practice to replace the relay when the pump is replaced.

Make sure to take all necessary precautions and follow the correct procedure to avoid any issues.

How to diagnose a faulty fuel pump

To diagnose a faulty fuel pump, you should first establish whether the problem is related to the fuel system. If the engine won't start, this may indicate a fuel pump issue.

Listening for the Fuel Pump

Listen for the fuel pump by putting your ear near it and turning the ignition on. If the pump is working correctly, you should hear an audible sound. If it's not working, it may create a humming or buzzing sound.

Hitting the Fuel Pump

You can hit the fuel pump with a sharp blow to see if this temporarily restores its function. This would indicate that the fuel pump needs to be replaced.

Using Starter Fluid

Pouring starter fluid into the throttle body of the engine may also indicate a fuel pump issue. However, this should be done with caution and the proper equipment, such as safety glasses and a fire extinguisher. Do not use starter fluid on a diesel engine.

Checking Diagnostic Trouble Codes (DTCs)

Use a scanner or code reader to check for DTCs, which are set by car owners and related to the air-fuel ratio.

Checking Fuel Trim

Car owners should also check the fuel trim with a scan tool, including both short-term and long-term fuel trim. Optimal fuel trim readings should be between -10 and 10. A reading below -10 represents a low fuel trim percentage, which could be caused by leaking fuel injectors, low fuel pressure due to contaminated fuel filters, or improperly functioning oxygen or coolant temperature sensors. A reading above 10 indicates a high fuel trim percentage, which could be caused by a dirty mass airflow sensor.

Checking Fuel Pressure or Volume

Checking the fuel pressure or volume will indicate whether fuel is reaching the tank. However, this does not always mean that the fuel pump is bad, as there could be other issues such as a dirty fuel filter or faulty pressure regulator.

Static Fuel Pressure Test

Performing a static fuel pressure test will help check for adequate fuel pressure and identify issues like faulty fuel pumps.

Checking the Fuel Pump Electrical Circuit

Before concluding that the fuel pump is faulty, check the fuel pump electrical circuit. The engine control module controls the fuel pump via a relay, and this method is used in continuous-style fuel systems, typically found in older vehicles.

Checking the Fuel Pressure Regulator

Check the regulator by disconnecting the hoses and noting whether the pressure increases or decreases. If the pressure remains normal, there is an issue with the regulator.

Other Potential Issues

There are also some other potential issues that could be causing problems, which are worth checking before replacing the fuel pump. These include:

• Checking electrical connections to the pump to ensure it's not an electrical problem
• Checking fuel pressure to ensure it is not below what is needed for proper fuel injection operation
• Checking for noisy or loud operation of the pump, which could indicate worn bearings or internal check-valve issues
• Checking for fuel leaks, which could be caused by a faulty o-ring or hose

How to drain the fuel tank

To drain the fuel tank of a 2000 Porsche Boxster, follow these steps:

Firstly, ensure you have a fire extinguisher to hand, and wear rubber gloves and eye protection. Have some old towels ready, and ensure you are working in a well-ventilated area.

Next, run the car so that the gas tank is nearly empty. Then, remove the gas cap to relieve any pressure in the tank.

Now, disconnect the battery and leave it disconnected for at least 30 minutes.

Then, locate the fuel pump relay in the driver's side footwell and remove it. You can now attach a hose to the pressure side hose from the top of the pump, and connect the car's battery terminals up to a 12-volt supply. Insulate both terminals carefully, and jumper the relay. Turn on the ignition, and the pump should turn on and begin to pump fuel.

Monitor the fuel level carefully, and shut the pump off when the external tank is full, or when the Boxster's fuel tank is empty.

How to remove the fuel pump

To remove the fuel pump from a 2000 Porsche Boxster, you will first need to prep the car. Remove as much gasoline from the car as possible.

• Always have a fire extinguisher nearby.
• Gasoline is highly flammable. When working around fuel and fuel line connections, do not disconnect any wires or electrical connections that may cause electrical sparks.
• Always remove the gas cap to relieve any pressure in the tank before working on the fuel system.
• Do not use a work lamp when working near fuel or fuel tanks. If you need extra light, use a cool fluorescent lamp and keep it far away from the pump.
• Gasoline vapours are strong and harmful, and can cause drowsiness. Always work in a well-ventilated area.
• Always disconnect the battery when working on the fuel system. Leave it disconnected for at least 30 minutes to allow any residual electrical charge to dissipate.
• Keep plenty of paper towels on hand, and wear rubber gloves to prevent spilling gasoline on your hands.
• Do not do anything that will create static electricity. Keep all cell phones and pagers at a safe distance.
• Run the car so the gas tank is nearly empty, and then remove the remaining fuel.

Now, remove the battery from the car. The lower battery tray acts as a retaining platform for the battery and a cover for the fuel pump area. Underneath this tray, you will see the top of the fuel tank sending unit. Disconnect the connector that mates with the sender. Squeeze and disconnect the fuel lines and breather hose that feed into the top of the unit. There may be some small fuel spillage here, so have paper towels on hand.

The sender is held in place by a big circular disc with risers on it. There is a special tool used to remove and tighten this black plastic ring. However, with a large flathead screwdriver or chisel and a small hammer, you can tap the plastic ring loose. Carefully remove the ring from the top of the sender.

Now, pull up on the top of the sender, and the entire assembly should come right out of the tank. There is a big, thick O-ring that seals the pump to the tank: remove it and put it to one side.

When reinstalling the pump, make sure that the fuel hoses inside the tank don't interfere with the proper operation of the fuel tank sender.

How to install the new fuel pump

To install the new fuel pump, follow these steps:

Firstly, ensure the fuel tank is almost empty. This will minimise problems if something goes wrong.

Disconnect the battery and leave it disconnected for at least 30 minutes to allow any residual electrical charge to dissipate.

Now, crawl underneath the car. The fuel pump is located in the bottom of the tank, with fuel pumped out of the top fuel tank cover. Remove the large plastic panel located in the very centre of the car by unscrewing the plastic nuts. Next, remove the foam fixture piece that wraps around the lines in the centre tunnel. Disconnect the fuel filter ground strap and loosen the clamp holding the filter.

Disconnect the lines to the filter by gently pushing on the grey tabs on opposite sides of the plastic connector. Have a bucket handy to catch the excess fuel when you release the connection.

Take the filter out by pulling it towards the rear of the car, then put it in your bucket and take it outside of your garage immediately. Let the garage sit empty for 15-20 minutes to allow fumes to clear.

Now, simply reattach the new filter in place of the old one, observing the direction of the arrows located on the filter. These arrows point in the direction of fuel flow, which is from the front (fuel tank) to the rear (engine). Check that the snap-fit connections are properly seated by gently tugging on them. Reattach the ground wire and tighten the clamp that holds the filter tight.

Finally, reinstall the foam piece and the large centre panel. Reconnect the battery and crank the car over to see if it starts. If the car starts and runs, the pump is working fine.

Safety precautions when working with fuel

Working with fuel can be dangerous, so it's important to take the proper safety precautions. Here are some detailed instructions to ensure your safety when working with fuel, specifically when replacing the fuel pump on a 2000 Porsche Boxter:

Before you begin

• Keep a fire extinguisher nearby in case of emergencies.
• Gasoline is highly flammable, so do not disconnect any wires or electrical connections that may cause sparks.
• Always remove the gas cap to relieve pressure in the tank before working on the fuel system.
• Do not use a work lamp when working near fuel or fuel tanks. If you need additional lighting, use a cool fluorescent lamp and keep it away from the pump.

During the fuel pump replacement process

• Disconnect the battery and leave it disconnected for at least 30 minutes to allow any residual electrical charge to dissipate.
• Keep paper towels and rubber gloves nearby to prevent spilling gasoline on your hands and to handle fuel-soaked items.
• Avoid creating static electricity by keeping cell phones and pagers at a safe distance.
• Always perform work in a well-ventilated area to avoid inhaling harmful gasoline vapors, which can cause drowsiness and impaired judgment.

General safety precautions when handling fuel

• Only store the minimum amount of fuel needed and use approved containers that are sealed tightly.
• Never siphon fuel with your mouth; use a pump or hose instead.
• Avoid prolonged skin contact with fuel, and wash skin thoroughly with soap and water if exposed.
• Refrain from smoking or creating any sources of ignition near fuel.
• Keep spill response kits nearby and follow environmental, health, and safety regulations in the event of a fuel spill.
• Ensure proper ventilation in fuel storage areas and regularly inspect storage equipment.
• Regularly train personnel on fuel handling procedures and encourage them to report any safety concerns promptly.

Frequently asked questions