Ford Taurus Fuel Pressure: Schrader Valve's Role

The 2004 Ford Taurus does not have a Schrader valve. Fuel pressure can be checked by listening for the pump to run for about one second when the key is turned to run but not crank. If the pump does not run, there is a problem with the pump or module. If the pump runs and then stops, turn the key to off and back to run and let it pump again. Repeat this process about three times and then try to start the car.

Fuel pressure specs

The fuel pressure specifications for the 2004 Ford Taurus are as follows:

• With the key on and the engine off, the fuel pressure should be between 30 and 55 psi.
• At idle, the fuel pressure should be between 26 and 45 psi.
• At 2000 rpm, the fuel pressure should be around 33 psi.
• At 3000 rpm, the fuel pressure should be around 33 psi.
• At 4000 rpm, the fuel pressure should be between 32 and 33 psi.

It is important to note that these specifications are for a 2004 Ford Taurus with a 3.0L OHV VIN "U" engine. The fuel pressure specifications may vary depending on the specific model and engine configuration of the vehicle.

Additionally, when diagnosing fuel pressure issues, it is recommended to use a scan tool that can read fuel pressure directly from the fuel rail pressure sensor. The fuel pressure values obtained from a mechanical gauge may not be accurate due to the electronic returnless fuel system used in the 2004 Ford Taurus.

Fuel rail pressure sensor circuit performance

A fuel rail pressure sensor circuit performance issue can manifest in a few ways. Firstly, the check engine light may illuminate, indicating that the Engine Control Module (ECM) has detected abnormal sensor input. Secondly, there could be engine start problems, such as hard starts or an inability to start the engine. Thirdly, poor engine performance may be observed, including reduced power and a rough-running engine. In some cases, the engine may also misfire. These issues are caused by disruptions in the fuel supply, leading to an insufficient or excessive amount of fuel being delivered to the engine.

To diagnose a fuel rail pressure sensor issue, it is recommended to check the voltages on the sensor and replace it if the values are outside the accepted range. Additionally, it is worth noting that a faulty fuel rail pressure sensor can be driven for a short period, but it is crucial to replace it as soon as possible to avoid more serious engine problems in the future.

Fuel filter replacement

Overview

The fuel filter on a 2004 Ford Taurus is located under the car, on the passenger side, near the rear door. It is attached to the frame rail in the fuel line.

Step-by-Step Guide

Note: It is recommended to drive the car up a ramp or park vertically near a ditch for easy access to the fuel filter.

• Disconnect the battery ground cable.
• Relieve the fuel pressure.
• Raise the vehicle.
• Place a bucket or pan under the fuel filter to catch any spilling fuel.
• Disconnect the R-clip fittings.
• Remove the fuel filter.

Installation

To install the new fuel filter, simply reverse the removal procedure, ensuring that the flow arrows on the new filter are correctly oriented.

Additional Tips

• It is important to pay attention to the flow arrows on the new fuel filter and replace each line and clip securely.
• The fuel system loses pressure fairly quickly at the filter once the ignition is turned off.
• It is recommended to reset the fuel filter switch and start the car after installation. It may take a few seconds or a couple of cranks for the car to start.
• Ensure you have the correct plastic clips for the fuel filter. Some aftermarket filters may come with the wrong size clips.
• It is possible to reuse old plastic clips, but it is not advisable.
• Be cautious when handling fuel and working underneath the vehicle. Do not lay under the car and look up at the filter when removing the tubes or the filter.
• Consider disconnecting the wiring harness from the inertia switch in the trunk instead of using the button to shut off the fuel supply.

Fuel pump replacement

Overview

The fuel pump is located inside the fuel tank of your 2004 Ford Taurus. It has a small electric motor that ensures pressurized gasoline flows to the engine to power the vehicle. The fuel passes through a filter, either inside the fuel tank or externally in the fuel flow line.

Signs of a Bad Fuel Pump

• Engine "chokes" or struggles to maintain speed
• Noises, backfires, and a sputtering engine
• Hesitation at start or take-off
• Overheating engine due to a bad fuel pump
• "Check Engine" light is on

• Siphon the fuel out of the tank.
• Remove the fuel tank from the vehicle.
• Access the fuel pump from the top of the tank.
• Remove the old fuel pump.
• Install the new fuel pump.
• Reattach the fuel tank to the vehicle.

Notes

Most fuel pumps will last for the life of the vehicle. However, if the pump fails, you will need to replace it. Signs of failure include a car that won't start or stalls after starting. Sometimes, the fuel flow can slowly become starved, causing the check engine light to come on. Additionally, if you hear a whirring sound from the fuel tank, it may indicate an impending fuel pump failure, as they do not normally make noise.

This job is moderately complicated and is best performed by a professional mechanic or dealership service department.

Cost Estimate

The average national cost for a fuel pump replacement across all vehicles is roughly between $611 and $894, including parts and labor.

Fuel pump duty cycle

The fuel pump duty cycle (FPDC) is the percentage of time that the pump is working, with 0% being off and 100% being the maximum. For example, a 35% duty cycle means the pump is on for 35% of the time and off for 65% of the time. This is how fuel pressure is regulated.

FPDC is important because it can indicate the health of the fuel pump. A high duty cycle may mean that the pump is working harder to maintain the required fuel pressure, which could be a sign of wear or that the bearing is starting to drag. In general, keeping the FPDC under 85-90% at full load conditions is recommended for pump longevity.

To calculate the duty cycle, you need to know the ratio of "on to off time". For instance, if the voltage is on for 0.3 seconds and off for 0.7 seconds in a 1-second cycle, the duty cycle would be 30%.

When diagnosing fuel pump issues, it is important to use a scan tool to observe the commanded duty cycle or speed, along with fuel pressure and engine speed. If the fuel pressure drops or takes a long time to recover after a load is put on the engine, it could be an indication that the pump is worn out.

In the case of the 2004 Ford Taurus, some owners have reported fuel pressure issues and have suspected a weak fuel pump. However, without specific data on the duty cycle and fuel pressure, it is difficult to make a definitive conclusion.

Frequently asked questions