This sounds like you may not have any power going to the fuel pump relay. The relay wires should have ground on two wires, power on one wire and switched power on another wire. To activate the fuel pump your ECU actually connects one of the ground wires to complete the circuit and send power to the fuel pump. If the wires all have power running through them, then it is likely you have a faulty relay. The wire coming from the fuel pump is the other ground wire. I would recommend having an expert from YourMechanic come to your location to diagnose your wiring as this can be very difficult and time consuming without the proper wiring diagram.
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There are several reasons why your fuel pump may not be working after replacing it. The most likely reason is that it was not installed properly. Double-check that it is securely hooked up to all fuel lines and electrical wires. One common mistake people make is installing the pump upside down.
If you there is no power to the fuel pump or the relay, then there may be a possible electrical issue with the vehicle. I would first verify that the main EFI, fuel pump, and ignition fuses are not blown, as these can sometimes cut off power to the fuel system.
A faulty fuel pressure regulator can cause a loss of fuel pressure. As a result, the engine may exhibit performance problems, such as hard-starting, rough running, stalling, and a lack of power.
Powered by the ignition and/or powertrain control module (PCM), the fuel pump relay`s main function is to provide the fuel pump with enough power. When the fuel pump relay isn`t working, then the fuel pump cannot either.
Step 1: Turn the key to run position. Locate the reset button to the fuel pump shut off switch. Press and hold the reset button for about 20 seconds. Note: The fuel pump shut off switch reset button is usually located either under the dash in the driver compartment or under the driver or passenger seat.
Once the vehicle determines the systems are safe, then the vehicle allows you to restart. The fuel pump shut-off switch is located behind an access panel on the right side of the luggage compartment. The fuel pump shut-off switch has a red reset button on top of it.
You might not have heard the term fuel pressure regulator, but as an imperative component of any EFI system, your vehicle will not operate without it. The fuel pressure regulator sees that the fuel rail builds up enough pressure to support the vehicle`s fuel injector system with the right amount of fuel.
A faulty fuel pressure regulator may result in engine misfires, reduction in power, poor acceleration, and a decrease in fuel efficiency. That said, the symptoms can also take place owing to other mechanical issues.
They are two different things. A regulator regulates fuel pressure to stay within a certain range (usually 50-60 psi) and a sensor reads the fuel system pressure for the ECU to monitor and adapt to whatever fuel pressure the sensor is reading.
When the key is turned on, the powertrain control module (PCM) closes the fuel pump relay, which activates the fuel pump for about three seconds to pressurize the fuel injectors.
The fuel pump has a check valve built into it that is supposed to keep pressure to the injection system when you shut down and vehicle sits. If the pressure drops then the pump has to prime the system to bring the pressure high enough to start and run the engine.
That pressure pushes fuel very quickly. In contrast, the fuel pressure created by mechanical fuel pumps is much less, usually in the 1–4 psi range. Second, this is important because the fuel system needs to be primed—the lines between the tank and the engine have to be filled with fuel.
To confirm that your pump has failed, check the pressure in your fuel lines with a fuel pressure gauge; if it reads zero, then your pump is likely dead. You can also check your car`s fuse box; a blown fuel pump fuse is another reliable symptom of a failed pump.
A small pipe called a venturi runs alongside the gas nozzle. When the end of the venturi pipe becomes submerged with the rising gas, it chokes off the air pressure that holds the nozzle handle open and shuts down the gas flow.
Easy…… use a push button as a start with one of your relay contacts(or an aux relay) as a hold-in across the start button. Your float switch then becomes a series stop switch. The latter would of course have to be normally closed during normal operation.
The most common sign of a bad fuel pump relay is an engine that cranks but doesn`t start. A fuel pump relay will typically fail in the open position, preventing voltage from reaching the fuel pump. As a result, the engine will be starved of fuel and refuse to run.
When you turn the ignition key or press the car`s start button, a large current is generated. The starter motor requires considerable current, and the ignition switch cannot be controlled. If there is no relay, it will burn out. If the starting relay fails, the vehicle may not start.
The fuel pump relay is a necessary component for the combustion engine model to function. The combustion engine needs fuel to run, and the fuel pump relay ensures that that engine gets what it needs. It is usually controlled by the ignition or the power control module.
A poor connection can cause enough resistance to lower the amount of voltage reaching the pump. This causes the pump to turn more slowly than it should, and can shorten the life of the pump. Replacing the vehicle side connector should solve the issues with poor connections, but sometimes causes another problem.
The average cost for a Fuel Pump Relay Replacement is between $65 and $73. Labor costs are estimated between $30 and $38 while parts are priced between $35 and $35.
Without the sensor hooked up the pump will run at a set speed and may cause engine to run at reduced power and throttle.
Without a regulator, the fuel would build pressure, damage the injectors and even blow out the rubber fuel hoses. It is possible but not a good idea to run such a car without a regulator.
You will find fuel pressure regulators typically located at the end of the fuel rail on mechanical return systems, or at the fuel tank in mechanical return-less fuel delivery systems.
The fuel tank pressure sensor is part of the fuel pump assembly and is mounted on top of the tank or inside the tank. It`s part of the evaporative emissions system (commonly referred to as “EVAP”) and reads pressure in the fuel system to detect evaporative leaks, such as a loose or faulty gas cap.
How long and what is the process to replace a fuel pressure sensor?
ANSWER : A professional mechanic would require roughly 5 hours. (If just the regulator is replaced that takes about 1 hour). Some parts, as noted below, cannot be re-used, you need a precision inch pound torque wrench, FSM instructions (and TSB updates if applicable; procedure was changed in 2007 for instance) and the system has to be bled when done.
Below is partial list of steps, copied and pasted directly from the service manual:
1. Disconnect battery and put protective material in front of the charge air cooler (CAC) or damage to the CAC may occur.
2. Remove air cleaner assembly.
3. Disconnect the oil drain tube from the crankcase vent oil separator.
4. Loosen the air cleaner outlet tube clamp and detach the air cleaner outlet tube from the turbocharger.
5. Remove the bolts, the crankcase vent oil separator and the air cleaner outlet pipe as an assembly.
6. Remove and discard the crankcase vent oil separator press-in-place gasket. (To re-install, tighten to 13 Nm (115 lb-in).
7. Disconnect the PCM electrical connector (BE SURE BATTERY IS DISCONNECTED FIRST!) and retainer. Disconnect the in-line electrical connector and position the engine wiring harness on the engine.
8. Remove the pushnuts and the glow plug module heat shield.
9. Disconnect the high-pressure fuel injection pump electrical connector and detach the retainer from the glow plug module bracket. Disconnect the glow plug module and the exhaust gas recirculation temperature (EGRT) sensor electrical connectors, detach the wiring retainer and position the wiring harnesses aside.
10. Remove the nut and position the ground strap aside. To install, tighten to 13 Nm (115 lb-in).
11. Remove the engine wiring harness bolt. To install, tighten to 13 Nm (115 lb-in).
12. Remove the heater supply tube nut. To install, tighten to 13 Nm (115 lb-in).
13. Remove the bolts and the glow plug module bracket. To install, tighten to 13 Nm (115 lb-in).
14. Remove the nut and position the transmission fluid indicator tube aside. To install, tighten to 8 Nm (71 lb-in).
Warning: Do NOT disconnect the glow plug electrical connector before dislodging the seal from the valve cover or the wiring harness may be damaged.
15. Using an appropriate tool, dislodge the glow plug wiring harness seals from the valve cover.
16. Disconnect the glow plug electrical connectors by pulling on the glow plug wiring harness tee above the seal. Remove the glow plug wiring harness.
17. Remove the nut and position the crankcase ventilation drain tube aside.
18. Disconnect the wiring harness retainer from the valve cover stud.
19. Disconnect the wiring harness retainer from the generator bracket.
20. Disconnect the A/C pressure switch electrical connector. Position the harness aside.
Warning: Do not bend or flex the heater supply tube or damage to the tube may occur.
21. Remove the stud bolts, bolts and the valve cover. Remove and discard the valve cover gasket. To install, tighten to 9 Nm (80 lb-in).
Warning: Contact with exposed fuel injector wiring, if energized, may result in electric shock.
Use care when working on or around energized fuel injector wiring. Fuel injector wiring supplies HIGH VOLTAGE to operate the fuel injectors of course, you disconnected the battery though.
22. Disconnect the fuel rail pressure (FRP) sensor electrical connector.
Warning: Fuel injection equipment is manufactured to VERY precise tolerances and fine clearances (think space shuttle). To prevent fuel system damage, it is essential that absolute cleanliness is observed when working with these components. Always install fuel system caps on any open orifices or tubes.
23. Remove the FRP sensor. To install, tighten the FRP sensor in 2 stages.
Stage 1: Tighten to 7 Nm (62 lb-in).
Stage 2: Tighten an additional 40 degrees.
24. Bleed the high-pressure fuel system.
If you feel like this job may be too overwhelming or run into any issues, consider YourMechanic to get it done. One of our mobile technicians can come to your home and replace the fuel pressure sensor at your own convenience.
