Fuel Pump Replacement – 2.5L NA

Overview

This guide outlines the procedure to replace the fuel pump on all Porsche 944 variants with an 8-valve engine configuration, covering both pre-1985.5 (1983–1985.5) and 1985.5 onwards (1986–1988) models. The fuel pump delivers fuel from the tank to the engine, and replacing it is necessary if it fails due to clogging, excessive wear, or related fuel system issues. Following these steps ensures a safe and effective replacement, preventing damage to the new pump by addressing potential system problems like a clogged fuel filter or failing pressure regulator.

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Tools Required

• Metric wrench set (10mm–13mm, 3/8 inch–1/2 inch)
• Metric socket set (10mm–13mm, 3/8 inch–1/2 inch)
• Hose clamp pliers
• Locking pliers
• Floor jack
• Jack stands or ramps
• Catch rags
• Drain pan

Parts Required

• Fuel pump (944 608 102 06)

Step-by-Step Procedure

Step 1: Depressurize the Fuel System

1. Locate and remove the fuel pump fuse to disable the fuel pump:

For Pre-85.5 models:
Remove Fuse 2 (15A) from the Auxiliary Fuse Panel, located under the dashboard on the driver’s side (left-hand drive).

For 85.5 Onwards models:
Remove Fuse 34 (15A) from the Central Electric Panel under the hood, supplied via the DME relay

2. Attempt to start the engine. If it starts, let it run until it stalls due to lack of fuel.
3. Disconnect the negative battery lead to ensure safety during the procedure.

Step 2: Raise the Vehicle

4. Using a floor jack, raise the rear of the vehicle and secure it on jack stands or place it on ramps for safe access to the fuel pump.

Step 3: Access the Fuel Pump

5. If equipped, remove the fuel pump cover at the bottom of the fuel tank:
   Unfasten the strap securing the cover to the tank.
   Remove the single 13mm bolt near the wheel well using a 13mm wrench or socket.

Step 4: Disconnect the Fuel Pump

6. Disconnect the electrical leads from the fuel pump:
   For some models, unplug the two-prong connector near the pump.
   For others, disconnect the lead directly from the pump.
7. Using hose clamp pliers or locking pliers, clamp the fuel line from the tank to the pump’s suction side to prevent fuel leakage. If using locking pliers, wrap the fuel line with a rag to protect it from damage.

8. Loosen the hose clamp on the suction line using hose clamp pliers and disconnect the line from the pump. Place catch rags and a drain pan under the line to catch residual fuel.

9. Using a metric wrench (typically 13mm), disconnect the discharge line from the fuel pump.
10. Loosen the hose clamp securing the fuel pump to its holder and slide the pump out.

Step 5: Install the New Fuel Pump

11. Compare the new fuel pump (944 608 102 06) to the old one to ensure all fittings match. Transfer any necessary fittings from the old pump to the new one if they are not included.
12. Slide the new fuel pump into the holder and tighten the clamp to secure it. Avoid over-tightening to prevent damage to the pump motor.
13. Reconnect the suction line to the pump and tighten the hose clamp.
14. Reconnect the discharge line to the pump using a metric wrench (typically 13mm).
15. Remove the clamp from the suction line.
16. Reconnect the electrical leads to the fuel pump, ensuring a secure connection.

Step 6: Reassemble and Test

17. Reconnect the negative battery lead.
18. Reinstall the fuel pump fuse (refer to Step 1 for fuse location).
19. Start the vehicle and check for proper fuel pump operation and any fuel leaks.
20. If equipped, reinstall the fuel pump cover by securing the strap and tightening the 13mm bolt.
21. Lower the vehicle from the jack stands or ramps.

Post Procedure Checklist

• Verify the fuel pump operates correctly by listening for its hum when the ignition is turned on.
• Inspect all connections for fuel leaks, especially at the suction and discharge lines.
• Ensure the fuel pump cover (if equipped) is securely fastened.
• Perform a fuel pressure test to confirm the system operates within specifications (refer to the Porsche 944 Workshop Manual for details).
• Check the fuel filter condition to prevent premature pump failure, replacing it if necessary.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube