How to Troubleshoot a Ford Taurus Fuel Systemby Chris Moore
The Ford Taurus' fuel system sends the gasoline to the injectors under proper pressure. Any problems in the fuel system can lead to a drop in performance and wasted fuel, or the car might not run at all. Routine troubleshooting of the Taurus' fuel system includes checking the exterior of the gas tank and fuel lines. If you need to check the system internally, test the fuel pump operation and the fuel pressure.
Inspect the gas tank cap for damage or corrosion. Replace the cap if its gasket has a broken or damaged sealing imprint.
Look over the fuel supply and return lines. Check for any cracks in the lines. Make sure the lines' connections to the injection system and the in-line fuel filter are tight.
Check the gas tank and filler neck for cracks, punctures or other damage. You need to raise the car on jack stands for this. Check the connection to the tank and filler neck, looking for a loose clamp or deteriorating rubber. Make sure the mounting brackets and straps securely attach the tank to the car.
Inspect all the metal lines and rubber hoses leading away from the tank. Replace or repair any loose connections, crimped lines or deteriorated hoses.
Relieve the fuel pressure before inspecting the system internally. The Taurus has an inertia switch reset button you can push to relieve the pressure immediately. This switch is in the trunk behind the trim panels on the right side (1996 to 1999 models) or driver's side (later models).
Fuel Pump Check
Make sure the fuel pump works. Remove the gas cap and listen near the filler opening while someone turns the ignition on. A whirring sound for a couple of seconds means the fuel pump is operating.
Check the fuel pump's fuse if you didn't hear the sound (this fuse is Number 10 in the fuse box). Replace the fuse if it is blown. If it blows again, check for a short in the fuel pump circuit. If the original fuse is good, test the relay operation by applying battery voltage to Circuit 238 in the fuse box (1998 or later models only).
Test the fuel pump with the ignition switch again. If you hear the whirring sound now, the fuel pump relay or its control circuit is bad. If you still get no sound, the problem can be the relay, control circuit or the fuel pump itself.
Connect a fuel pressure gauge to fuel pressure test port (you need to remove its cap). The gauge must have Schrader valve adapter. Turn the ignition on and wait for the fuel pump to pressurize the lines.
Observe the gauge's reading, once it has stabilized. For a 1996 to 2000 Taurus, the pressure should be 37 to 45 pounds per square inch. On newer models, it should be 45 to 56.
Start the engine and let it idle. The fuel pressure should now be 26 to 45 psi for a 2000 or older Taurus and 50 to 56 for newer models.
Remove the vacuum hose from the fuel pressure regulator. Test the fuel pressure regulator if the fuel pressure doesn't rise several psi with the hose removed. Connect the vacuum line back immediately.
Pinch the fuel return line shut if the pressure reading was low and observe the gauge again. Replace the pressure regulator if the pressure sharply rises now. If it doesn't rise, check for a restriction in the supply line. If there is no restriction, you have a defective fuel pump.
Check for a blockage in the fuel return line if the pressure was too high. Turn off the engine, disconnect the line and blow into it. Replace the regulator if there is no blockage.
Use a vacuum gauge on the regulator's vacuum hose to check for vacuum with the engine started. Replace the regulator if you get a good amount of vacuum. If there is no vacuum, check for a clogged vacuum port or hose.
Turn off the ignition and check the fuel pressure gauge after 5 minutes. If the pressure drops more than 5 to 7 psi, you could have a defective fuel pump, leaking fuel lines or injectors or fuel pressure bleeding to the return line.