Fuel Pump Suction Strainer - Removing, Cleaning, and Replacing

Introduction

In addition to the in-line fuel filter on the pump discharge side, 944 models have a strainer on the suction side of the fuel pump. This strainer is part of the fuel tank outlet fitting and is not commonly known or serviced. A clogged suction strainer can cause low fuel system pressure or inadequate pump delivery — symptoms identical to a failing pump.

Recommended diagnostic sequence for low fuel pressure:

1. First replace the in-line fuel filter.
2. Then clean or replace the fuel pump suction strainer.
3. If neither resolves the problem, consider replacing the fuel pump.

A leaking seal at the strainer fitting can also cause fuel tank leaks at that location. If a leak is present at the bottom of the tank near the outlet fitting, replace the O-ring seal using the steps below.

Tools

• Floor jack and jack stands
• Enough containers to empty the full fuel tank (approximately 20 US gallons / 75 L capacity)
• 17 mm deep socket and ratchet or 17 mm wrench
• Catch rags

Parts

Part Number	Description	Model	Year
928 201 081 04	Screen (pump suction strainer)	944, 944S, 944S2, 944 Turbo	All
928 201 187 02	Strainer O-ring seal	944, 944S, 944S2, 944 Turbo	All

Procedure

1. Check the fuel gauge to estimate how much fuel is in the tank. If the gauge is inaccurate or non-functional, assume the tank is full and prepare approximately 20 gallons (75 L) of container capacity.

2. Disconnect the battery negative lead.

3. Raise the rear of the vehicle with a floor jack and support on jack stands.

4. If equipped with a fuel pump access cover at the bottom of the fuel tank, remove it. The cover is held by a retaining strap and a single 13 mm bolt near the wheel well.

5. Locate the fuel line running from the bottom of the tank to the suction side of the fuel pump and pinch the rubber section with a hose clamp.

6. Using a flat-tip screwdriver, loosen the hose clamp at the pump suction fitting and disconnect the hose from the pump. Have catch rags and a container ready for residual fuel.

7. Place a container under the fuel line and loosen the hose clamp to begin draining the tank. When the container is full, pinch the line again with the hose clamp to pause flow. Repeat until the tank is fully drained. Fuel collected in clean containers can be reused.

8. Once the tank is drained, loosen the hose clamp at the fuel tank outlet and remove the hose from the outlet nozzle.

9. The tank outlet is a round cover plate with a nozzle extending downward. At the base of the nozzle is a hex head used for removal.

10. Using a 17 mm deep socket or wrench on the hex, turn counter-clockwise to remove the nozzle and strainer assembly. Have a container ready — the bottom of the strainer extends below the nozzle, so a small amount of additional fuel will drain when the strainer is removed.

11. Inspect the strainer screen for debris on the outside. Also check the base of the strainer for accumulated debris — remove carefully with a probe, avoiding damage to the screen mesh.

12. Clean a clogged strainer by backflushing with fuel or carburetor/choke cleaner through the nozzle, and by blowing low-pressure air (10 psig maximum) back through the nozzle to dislodge debris. If any holes or tears are found in the screen, replace the strainer.

13. Install a new O-ring seal on the strainer. Coat the seal with a small amount of molybdenum grease to lubricate it during installation and prevent cutting or abrasion.

14. Thread the strainer nozzle back into the tank outlet and tighten with the 17 mm wrench or deep socket.

15. Reconnect the fuel hose to the strainer nozzle and fuel pump, tightening both hose clamps.

16. Refill the fuel tank and check the strainer fitting and fuel lines for leaks.

17. Install the fuel pump access cover if equipped.

18. Remove the vehicle from jack stands.