Troubleshooting - Fuel System
Symptom-driven guide to diagnosing excessive fuel consumption and fuel smell in the passenger compartment on the Porsche 924, 944, and 968.
Vanskelighetsgrad: Middels2 min lesingGjelder for: 924 · 944 · 944S · 944S2 · 944 Turbo · 968
Denne prosedyren er ikke oversatt ennå og vises på engelsk.
Introduction
This troubleshooting guide is intended to help identify and repair fuel system problems. Symptoms covered:
- Excessive Fuel Consumption
- Strong Fuel Smell In Passenger's Compartment
Excessive Fuel Consumption
| Possible Cause | Checks | Procedure |
|---|---|---|
| Dirty Air Filter | Check / change air filter. | N/A |
| Bad O₂ Sensor (if equipped) | Check sensor and replace if necessary. | FUEL-18 |
| Poor Ignition System Function | Check the condition of the distributor cap and rotor. Check the condition of the spark plugs and spark plug wires. | IGN-04 |
Strong Fuel Smell In Passenger's Compartment
| Possible Cause | Checks | Procedure |
|---|---|---|
| Fuel Level Sender Gasket | Locate the fuel level sender (ELECT-13) and check the condition of the gasket around the sender cap (1985.5 and newer). If the gasket appears hard or brittle, remove the sender and replace it. Part number: 944-201-327-00. On early 944s the sender uses an O-ring seal (part number 477-919-133) and five cheesehead screws each with their own seal ring (part number M 013 802 1). Fuel smell on early cars can result from any of these seals failing. | ELECT-13 |
| Fuel Tank Ventilation System | The fuel tank ventilation system runs hoses from the tank along the bottom of the vehicle on the right-hand side, into the engine compartment, along the back of the firewall, to a charcoal filter canister in the left fender well (remove the interior fender well cover to locate the canister). Any loose, cut, or leaking fuel line — or a split charcoal canister — will produce a strong fuel smell inside the passenger compartment. | N/A |
| Fuel Filler or Fuel Reservoir System Leak | Rubber hoses and sleeves in the fuel filler and fuel reservoir system can cause fuel smell if they develop holes or if hose clamps come loose. These components are located in the rear hatch area behind the carpet on the fuel filler side of the car and behind the pillar panel on the same side. Specific problems: (1) Ventilation valves — if stuck, they cause fuel vapors to leak into the cabin. A "whooshing" sound when opening the fuel filler cap indicates a stuck valve. Early system uses a shut-off valve (928 201 083 02) and a ventilation valve (810 201 186 A). Late system uses only the shut-off valve (928 201 083 02). (2) Leaking fuel cap gasket — early cars: 477 201 553; late cars: 944 201 553 00. (3) Elongated fuel filler neck — repeated fueling can distort the filler neck over time so the cap no longer seals. The neck is a replaceable sleeve: early cars (chassis code up to 94EN4 00060): 931 201 281 01; all other 944s: 931 201 281 02. | N/A |
Fuel Filler and Reservoir System Diagrams
Early Fuel Filler and Reservoir (Pre-1985.5)
Late Fuel Filler and Reservoir
Emneord:fuelfuel smellfuel consumptioncharcoal canisterfuel sendervapor