I get no fuel pressure

I have a Lincoln town car 2000 all my fuses have powers even the relays but my Iam getting no gas pressure
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
It sounds like you have a bad fuel pump. You should also check the fuel shutoff switch, which is designed to kill the power to the fuel pump in case of an accident. It can be reset by locating it in the trunk, behind the trim piece on the driver side, and pressing the red button. If that does not work, the fuel pump is the likely cause of your concern. A certified technician, like one from YourMechanic.com, will be able to determine the exact cause of your concern, and complete the repair.

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These include a bad fuel pump relay or control module, a blown fuse, a wiring fault, loose or corroded wiring connector at the pump, or even an issue with the anti-theft system. Until these other possibilities have been checked out and eliminated, the fuel pump should be the last thing that`s replaced.
The fuel pressure is monitored by the engine control unit via a pressure sensor and regulated via a flow control valve installed in the pump. This fuel pressure regulator is attached directly to the high-pressure pump.
The causes for this imbalance of fuel pressure typically include either a bad fuel regulator or a clogged return line. The easiest way to tell that it`s time for you to take your vehicle in to AutoScope`s team for a closer look is when your check engine light turns on.
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.
The fuel supply pump, often referred to as the lift pump, is responsible for drawing fuel from the tank and delivering it to the high pressure pump. Modern day fuel pumps can be electrically or mechanically driven by the engine.
The plunger`s position is controlled by the ECU, based on the required engine output and the current fuel pressure measured by the fuel pressure sensor. The fuel metering valve solenoid is powered from a system relay on the positive side and the ECU switches the negative side to the ground.
A malfunctioning fuel pump that drives very little or no fuel at all in the engine can be caused by a bad ground wire connection to the chassis of your vehicle. This issue is known to be also a work of rust and corrosion.
Low Fuel pressure is where most problems occur for fuel supply. There are two faults that could be causing this, diesel injectors or diesel injector rail not holding the fuel within the system and poor fuel supply to the diesel injectors or diesel injector rail.
When the throttle closes, pressure rises and readings from the MAP sensor tell the computer to reduce the amount of fuel going into the engine. A faulty MAP sensor will usually trigger a “check engine” warning light.
A fuel pressure regulator (FPR) is a device that controls the pressure of fuel supplied to the fuel injectors on an engine.
No matter what operating condition (short of demanding more fuel than the pump can supply), pressure in the rail will always be 58psi (or pretty close).
The PCM outputs a duty cycle command between 5% and 51% to the fuel pump driver module (FPDM) to control system pressure, using a fuel rail pressure sensor (FRP) for feedback.
The basic operating system for an electric fuel pump is relatively simple. 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.
As the engine is cranked, the crankshaft position sensor indicates to the PCM that the engine has reached a minimum cranking speed of about 250-300 rpm. At that point, the PCM re-activates the fuel pump.
The idle air sensor, coolant temperature sensor and EGR sensor all change things within the engine and fuel delivery system.
Fuel level sensors are used to monitor fuel levels in fuel tanks of various kinds of vehicles, locomotives, ships, vessels etc. It can also be used to monitor the fuel of static heavy equipment`s such as generators and fuel station tanks.
Some possible causes for this issue may be a blown EFI (Electronic Fuel Injection) main or computer fuse, a defective ignition module, a wiring issue, or perhaps even a defective engine control unit.
Look for these warning signs: Rich air-fuel ratio: Look for rough idle, poor fuel economy, slow acceleration and a strong smell of gasoline (especially at idle) Lean air-fuel ratio: Look for surging, stalling, lack of power, hesitation on acceleration, backfiring through the intake, and overheating.
If the MAP sensor goes bad, the ECM can`t accurately calculate engine load, which means the air-fuel ratio will become either too rich (more fuel) or too lean (less fuel).
The pressure transducers can also be used to monitor system pressures to diagnose hard-start problems. So much of the diagnostic process for fuel pumps can be performed from the driver`s seat of the vehicle with a scan tool. This makes you a more productive technician and the diagnosis more accurate.
Common signs include the Check Engine Light coming on, the car not feeling right when running, and issues with starting the car.
The fuel pressure sensor usually has three wires and operates on five volts. As the fuel pressure increases, the resistance changes. The sensor monitors fuel system pressures and the performance of the pump. If the sensor is not getting a clean five volts, the voltage on the signal side will change.
The throttle determines how much air and fuel is required based on the vehicle`s current speed and demand on the engine.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

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.

Read Full Q/A … : I get no fuel pressure

Just replaced my fuel pump but its not getting any power tested fuel pump relay and fuel fuse both good tested the wires all good.
ANSWER : You need to look at the theft light on dash to make sure it comes on and goes off when you turn the key to the on position. If light comes on and stays on then your theft system is causing the fuel pump to not be engaged. I recommend you check the theft system and then scan the computer for theft system codes. You may need to reprogram the keys to work or you have an bad sensor for the ignition key in the steering column.

Read Full Q/A … : I get no fuel pressure

Installed new delphi fuel pump and fram fuel filter. still no pressure on fuel rail valve and wont start. 2003 Chevrolet Tahoe
ANSWER : Hi there – I suspect you have weak power getting to the fuel pump. I would first check the voltage coming out of the fuel pump relay. If the contacts in the relay are burned, you will not get reliable current flow to the pump. Check the fuel pump ground as well (voltage drop across the ground, not just continuity). I recommend a fuel system inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Read Full Q/A … : I get no fuel pressure

I have a truck that won’t run and is not getting gas to the engine. Fuel pump is running, have a new filter and new fuel pressure
ANSWER : Hi There,
It sounds like you may have a clogged fuel injector or potentially a faulty injector that is fried internally. I would suggest testing them if you have access to a multi meter. Disconnect the injector from the electrical connector and set your multi meter to Ohms mode and measure the resistance of the injector. After testing all injectors, compare the resistance. They should be the same or very close. If they are not, they will likely need to be replaced.

Read Full Q/A … : I get no fuel pressure

I have a 1981 e-350 with dual fuel tanks the p.o. added a third tank and 3 electric fuel pumps along with sepparate gauges and swi
ANSWER : The switch you are referring to is vended with the required electrical and fuel schematic (I just looked in the box) that answers your installation question. If you want an advance view, here is a link as well. Yes, you need a return line and just refer to the aforementioned link. If you are retrofitting back to OEM, I strongly encourage you to buy the original Factory Service Manual (FSM). There are lots of details attending this system and obviously it is difficult to recount it all here. The FSM will make your life much easier and you can then make sure your installation is perfect. Alternatively, YourMechanic can dispatch a certified mechanic and perform the whole retrofit and check out if you desire. Just request and schedule a generic service such as fuel pump service and the mechanic will come to your location and estimate the parts and labor required. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Read Full Q/A … : I get no fuel pressure

the car is acting like its getting to much fuel. changed the fuel pump, fuel filter, and the fuel pump relay.
ANSWER : There could be a few things contributing to your problem. You are correct that clogged or sticking fuel injectors and possibly the fuel pressure regulator could be faulty. A plugged catalytic converter can also cause the vehicle to bog down. A failing throttle position sensor can cause the symptoms you describe as well. I suggest having a certified technician, like one from YourMechanic.com, do a few tests to determine the exact cause of your starting concern.

Read Full Q/A … : I get no fuel pressure

Turn ignition on fuel pressure goes to 60 lbs two seconds and fuel pump relay clicks pressure drops 5 lbs then slowly drops to 0to
ANSWER : It sounds like this fault may have more going on than just the fuel delivery issue. The vehicles ECU will command the fuel pump to turn on normally when a vehicle is started. If the car only primes for the second when the key is turned, then for some reason the ECU may be pulling the fuel.

This can happen due to a failure with various sensors or ignition component, such as the oil sender, ignition switch, ECT sensor, or various other failed sensors. If the car has codes stored in the ECU it may lead to more information as to what is going on. A qualified technician will be able to diagnose this fault no start fault and perform any repairs required.

Read Full Q/A … : I get no fuel pressure

Fuel pressure
ANSWER : Hello,
You may want to try checking 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.

Read Full Q/A … : I get no fuel pressure

Eric smoalih

I am a certified master technician with the National Institute for Automotive Service Excellence (ASE), and I have been working as an auto mechanic for over 15 years. I am passionate about my work, and I take great pride in helping people keep their cars running smoothly.