Where to troubleshoot fuel issue?

Hey yall. Thanks for the add.

Have a issue going on.. 07 ford f150 147000 miles. Issue started yesterday. Went out and it would continue to turn over trying to start. Sounded like it was not getting fuel. Reset the fuel pump reset still would not start. So my husband pumped the footfeed and then held it down to the floor and it started. It continues to start fine however the check engine light came on tonight and we pulled the code and got p0191 which is the fuel rail pressure sensor. Anyone else have this happen? Been told it is that sensor the fuel pump pressure module or the fuel pump?

Experienced mechanics share their insights in answering this question :
Hello, thank you for writing in. The issue could be any of the components you mentioned. There are several tests you can do, and you will want to pick the tests to perform first that are easiest for you to do with the tools available to you. One common test is to install an in-line gauge at the engine and check for fuel pressure. If it is in fact low, then you know you have a pump or module issue. If the pressure is within manufacture specification, you know the problem is likely the sensor failing. With the issues you have been having starting, the mileage of the vehicle, and the age of the vehicle, I would not be surprised to see the pump starting to fail. Keep in mind the fuel filters also need to be replaced periodically (some every 50,000 miles), and it should be looked into as well. The filter will also restrict flow and pressure. The sensor can also have electrical testing done if you have access to a multi-meter. Only further testing will tell. For more diagnostic help, contact our service department to schedule an appointment.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

1. Checking for FPR Fuel Leaks
  1. Open the hood and locate the fuel pressure regulator on one end of the fuel rail. …
  2. Check the vacuum hose for a tight connection. …
  3. If you see any signs of fuel in the vacuum line, the diaphragm inside the pressure regulator has a leak and you need to replace the regulator.
1 juin 2022
Correct Ford F-150 tire pressure is 35 psi for all four tires—but what happens if your tire pressure monitoring system is malfunctioning? The recommended tire pressure for a Ford F-150 pickup truck is 35 pounds per square inch (PSI) for all four tires.
If the fuel pump doesn`t meet the required pressure specification, then the fuel pump may be failing to pump fuel to the engine. A typical port-injected vehicle requires fuel pressure between 30 and 80 PSI.
Low fuel pressure can lead to engine misfires, low acceleration, rough idles, and engine stalls. If your check engine light is on and your car has been stalling out, you may have a fuel pump failure.
Low fuel pressure can lead to engine misfires, low acceleration, rough idles, and engine stalls. If your check engine light is on and your car has been stalling out, you may have a fuel pump failure.
Fuel pressure can be checked by attaching a gauge to the Schrader valve fitting on the fuel injector rail, or by teeing the gauge into the fuel supply line if the fuel system lacks a test fitting.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

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.

Where to troubleshoot fuel issue?
ANSWER : Hello, thank you for writing in. The issue could be any of the components you mentioned. There are several tests you can do, and you will want to pick the tests to perform first that are easiest for you to do with the tools available to you. One common test is to install an in-line gauge at the engine and check for fuel pressure. If it is in fact low, then you know you have a pump or module issue. If the pressure is within manufacture specification, you know the problem is likely the sensor failing. With the issues you have been having starting, the mileage of the vehicle, and the age of the vehicle, I would not be surprised to see the pump starting to fail. Keep in mind the fuel filters also need to be replaced periodically (some every 50,000 miles), and it should be looked into as well. The filter will also restrict flow and pressure. The sensor can also have electrical testing done if you have access to a multi-meter. Only further testing will tell. For more diagnostic help, contact our service department to schedule an appointment.

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.

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.

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.

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.

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.

Replaced fuel pump. Car won’t start. 2002 Infinity I35
ANSWER : Hi there – the metal component you describe is a fuel check valve on the fuel return line. Its function is to maintain a small amount of pressure in the fuel system so that starting does not require the fuel pump to run very long before the engine will start. Having replaced the fuel pump and fuel filter, I would check fuel pressure while the car is running. This is to check the fuel pump relay for burned contacts that won’t support full electrical current to the pump, and for proper fuel pressure – a malfunctioning fuel pressure regulator could also restrict power and higher speeds if pressure is too low. I would recommend an inspection of the fuel system 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.