Fuel Pressure Regulator Replacement

Overview

This procedure provides general information about the fuel pressure regulator (FPR) and explains how to replace it on a Porsche 944 S / S2 with a 16v engine. The FPR controls fuel pressure in the fuel rail, ensuring the engine runs smoothly. A faulty FPR can cause rough running, stalling, or even prevent the engine from starting, often leading to unnecessary replacement of other components like the DME or fuel pump. Replacing it is a straightforward task for someone with mechanical experience, and this guide will walk you through it step-by-step.

Tools Required

• 10mm (3/8 inch) socket and ratchet
• Flat tip or Phillips head screwdriver
• Catch rags
• Safety glasses
• 0-100 psi fuel pressure gauge (optional but recommended)
• Adapter for fuel pressure gauge to fuel rail (11mm x 1.50mm female threads)

Parts Required

• Fuel Pressure Regulator – 944 110 198 06 (specific to 944 S / S2, 1989-1991, engine code M44.41)

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Fuel Pressure – Checking

Step-by-Step Procedure

Step 1: Disconnect the Vacuum Line

1. Locate the fuel pressure regulator on the return side of the fuel rail. Disconnect the vacuum line attached to it by gently pulling it off.

Step 2: Prepare for Fuel Line Removal

2. Place a catch rag under the fuel line connection to the regulator to catch any fuel that may spill.

Step 3: Disconnect the Fuel Line

3. Use a flat tip or Phillips head screwdriver to loosen the hose clamp securing the fuel line to the regulator. Carefully disconnect the fuel line. Be cautious, as the system may still be pressurized, and fuel could spray out.

Step 4: Remove the Regulator

4. Wear safety glasses and cover the regulator with a rag for protection. Using a 10mm (3/8 inch) socket and ratchet, remove the retaining bolts holding the regulator to the fuel rail.
5. Gently rock the regulator back and forth until it comes free from the fuel rail.

Step 5: Install the New Regulator

5. Take the new fuel pressure regulator (944 110 198 06) and insert it into the fuel rail. Secure it by tightening the retaining bolts to 10 Nm (7 ft-lbs) using a 10mm (3/8 inch) socket and ratchet.

Step 6: Reconnect the Fuel Line

6. Attach the fuel line to the new regulator and tighten the hose clamp using a flat tip or Phillips head screwdriver.

Step 7: Reconnect the Vacuum Line

7. Push the vacuum line back onto the regulator’s vacuum port until it’s secure.

Post Procedure Checklist

• Check for fuel leaks around the regulator and fuel line connection.
• Start the engine and ensure it runs smoothly without stalling.
• If you have a fuel pressure gauge, follow this link to ensure this step – Fuel Pressure – Checking – of the process is followed accurately to confirm pressure is within specs (typically 2.5-3.0 bar for the 944 S2).

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manual, Volume 1
• Youtube

Image showing the fuel pressure regulator location on the 944 S2 fuel rail (plastic cover removed).