How To Tell If Your Fuel Pump Needs Replacing

Posted on: by
Fuel Pump Assembly 1986 Bronco II CC Image courtesy of Marion Doss on Flickr

Fuel Pump Assembly 1986 Bronco II CC Image courtesy of Marion Doss on Flickr

Your fuel pump is obviously important for your car, and it would seem as if your vehicle couldn’t move without one. That’s not always true, though. Some vehicles can limp along with a malfunctioning fuel pump for a few blocks or even miles.

But driving with a poorly performing fuel pump is not good for your vehicle, so it’s important to look out for some signs of trouble before you end up stranded or stalled out in traffic.

The fuel pump pumps fuel from your vehicle’s tank to the engine. If the fuel pump malfunctions, your engine will receive less fuel than it needs. There are some common symptoms for such a situation.

The first and most obvious symptom is that your car may not start at all, or it might start poorly. This poor start will take the form of a sputtering, stuttering, stammering sort of start, as if your car’s engine is only getting a trickle of fuel instead of the amount it needs. Your car may also stall during operation because the fuel pump is bad.

Vehicles can sputter and stall for a variety of reasons, so here’s a follow-up test. Pull your vehicle in the garage or other silent environment. When it’s not running, put the key in the ignition and turn it to the “ON” or “accessory” position. (Don’t try to start the engine.) If you have fuel injection and an electric fuel pump, the pump should start up, making a clicking or buzzing sound.

After performing the above test, if you can’t hear the fuel pump turn on, try this test. Using a fuel pressure gauge, test to make sure there’s enough fuel reaching the engine. You can take your vehicle to a technician for this test, or purchase a fuel pressure gauge at an auto parts store and do it yourself. Near the engine there should be a fuel pressure valve where you can attach the gauge. Find the recommended fuel pressure in ChiltonDIY. Compare your measurement of the fuel pressure with what it should be. If there is less pressure than there should be, that’s a sign that your fuel pump may be faltering.

Of course, there could be a few other problems causing incorrect fuel pressure, such as an obstruction in the fuel line or a bad fuel pressure regulator. If your fuel pressure is too high, suspect the fuel pressure regulator. For more information on diagnosing a fuel pump problem, check out Chilton’s online database for detailed instructions, images, and tips from our certified expert technicians to help you determine whether you need to replace your fuel pump or fuel pressure regulator, clean out the fuel lines, or something else.  Learn more about how to keep your car in tip top shape!

753 Responses to “How To Tell If Your Fuel Pump Needs Replacing”

  1. Duane says:

    I have a 2004 chevy silverado 1500, small v8-4.8L Truck will start but only stay running if the rpm is high. If I let off the gas to idle, the truck goes dead. Any thoughts?

    • ChiltonDIY says:

      Hi Duane.
      I would check for diagnostic trouble codes (DTCs) that may be stored in your truck’s powertrain control module (PCM). (You will need a scan tool.) This may help point you in the correct direction.
      You will want to determine whether it is a fuel or an ignition issue.
      I would also test the fuel pressure.
      General Motors has issued several technical service bulletins (TSBs) related to engine stalls and idle issues. Check the TSB section of your ChiltonDIY subscription for the 2004 Silverado.
      General Motors created troubleshooting procedures for “Rough, Unstable, or Incorrect Idle and Stalling” conditions, find these in your ChiltonDIY by searching for “incorrect idle” or by following this PATH: Engine Performance & Emission Controls > Engine Controls – 4.8L, 5.3L, And 6.0L > Diagnostic Information And Procedures > Symptom Diagnostics > Rough, Unstable, Or Incorrect Idle And Stalling.

  2. Andrew Alvarez says:

    i have a 95 GMC sonoma… when i drive cuople of yards it runs fine… then at a stop light i take off… it feels heavy no power an shakes… i turn off the truck an turn it back on … an it runs good for a couple of yards… an i have to do the steeps all over again…. would it be the fuel pump?

    • ChiltonDIY says:

      Hi Andrew,
      We need more information about your Sonoma, what size engine does it have?
      If you have the 4.3L engine, we’ll need a number from your VIN (vehicle identification number). If it is equipped with a 4.3L engine, what is the 8th number in the VIN?
      If you give us the full VIN, we can be sure we have the correct year, as sometimes a “95” model is built in a prior year or a successive year. (We won’t publish the complete VIN number.)
      Thanks!
      PS You can find the VIN on your auto insurance communications, your vehicle registration or state registration renewal requests, and on the Sonoma itself.
      The VIN is stamped on a plate located on the top left hand side of the instrument panel, so it can be seen by looking in through the windshield from outside the Sonoma. It is also on various other anti-theft labels found throughout the vehicle.
      The VIN is a seventeen digit sequence of numbers and letters which can be important for ordering parts and for servicing. The VIN plate is part of the Federal Vehicle Theft Prevention Standard and cannot be removed or altered in any way. The 8th digit of the VIN identifies the factory equipped engine while the 10th digit will give the vehicle model year.

      • Andrew Alvarez says:

        its a 2.2l standerd

        • ChiltonDIY says:

          Andrew,

          It could be a faulty fuel pump, check the fuel pressure to make sure it is within specification. From the navigation tree, find the specification for the 2.2L engine in your ChiltonDIY by following this PATH: Engine Mechanical > Specifications > Gasoline Engine Tune-Up Specifications.

          Ignition and/or engine timing could also cause the symptoms your Sonoma is exhibiting. Have you tried scanning your truck for diagnostic trouble codes (DTCs)?
          I would look for ignition malfunctions. Check the ignition coils and ignition wires, sometimes they will short under a heavy load.

  3. Luis Torrez says:

    I have a 2002 ford Taurus’s and everytime I start it up it would turn right off, and after that would happen I would have to jumpstart it, and right after ill jumpstart it, it would turn on idk if it might be a bad fuel pump or what..

    • ChiltonDIY says:

      Luis, it could be a faulty fuel pump, or a faulty idle air control (IAC) valve.
      First, have the battery charged and load tested. Once your battery is fully charged, try starting your Taurus.
      Test the fuel pressure with the vacuum hose connected at the regulator. Your fuel pressure should read within the specifications. Follow this PATH: Engine Mechanical > Specifications > Gasoline Engine Tune-Up Specifications in your ChiltonDIY subscription for the correct specifications.
      Inspect the fuel pressure regulator and don’t forget to check the fuel filter!
      With a scan tool check for history codes (diagnostic trouble codes or DTCs).
      Review the coolant temperature readings and the IAC duty cycle.
      The IAC valve adjusts the engine idle speed. The valve is located on the side of the throttle body. The valve is controlled by a duty cycle signal from the PCM and allows air to bypass the throttle plate in order to maintain the proper idle speed. Do not attempt to clean the IAC valve. Carburetor tune-up cleaners or any type of solvent cleaners will damage the internal components of the valve.
      There is a technical service bulletin (TSB) that may apply. In your Chilton subscription for the 2002 Taurus, go to “TSBs” and then filter by symptom. Choose the symptom: “Engine stalls.”

  4. Jim Scully says:

    I have a 1999 Silverado K2500 7.4L. I start the truck and it will idle smooth all day long if left in the same spot. As soon as you step on the throttle, the engine falls flat on it’s face, burping through the throttle body and trying to die, yet as soon a you lift off the throttle it settles back into a smooth idle. I replaced the fuel pump and filter about 6 months ago and replaced the fuel pressure regulator on Christmas Day. I still have the hot restart issue as well as the issue described above. I went out today and put a test gauge on the rail and am reading 18lbs static and I think I saw it peak at 22lbs while running. You shut it off and it takes a fair amount of time for the pressure to bleed back down. My question is, how do I determine if my low pressure is caused by a weak pump or a bad newly purchased FPR?

    • ChiltonDIY says:

      Hello Jim, that is a nice photo!
      With the ignition ON leaving the engine off (zero vacuum), the fuel pressure at the pressure test connection should be 55–62 psi.
      If the pressure is low, poor performance could result. If the pressure is too high, excessive odor may result. Sounds like a faulty pump. Do you have dual fuel tanks? If so that could be an area to look.

  5. james says:

    I have a 1997 Ford Explorer. Have been told by a mechanic that it is a 80% probability I have a bad fuel pump. The only problem I have is sometimes not starting. Then several hours later it will start. Always runs good if it starts. Strange.

    • ChiltonDIY says:

      James, I would inspect the fuel pump, the electronic engine control (EEC) relay, and the idle air control (IAC) valve, as an issue with one of them could cause the symptoms you describe.
      Make sure the relay connections that may be in the harness or the junction block are clean.
      Does your truck have any diagnostic trouble codes (DTCs) stored in its history?
      Verify that you have no fuel pressure when the vehicle won’t start. The fuel pressure should read 35-40 psi with the key on and the engine off.
      Don’t forget to make sure it is not an ignition problem.
      The idle air control (IAC) valve could cause hard starting conditions. If the IAC is stuck it usually starts and stalls. Sometimes a faulty IAC valve will not set a DTC. This is usually happens when the engine is cold, or the first start of the day.
      There is a technical service bulletin (TSB) that may apply. In your ChiltonDIY subscription for your Explorer, select “TSBs” and a list of the bulletins that apply to your vehicle will appear. You can filter the results by selecting “symptom” and then choosing “engine won’t start.”

  6. lilmo says:

    Hi I have 2006 Chevy cobalt and it starts after 2 tries only first thing in the morning or after a long period

    • ChiltonDIY says:

      Hi there.

      Test your fuel pressure and scan for diagnostic trouble codes (DTCs).

      If everything checks out okay, try replacing your fuel filter, and perform a fuel injector cleaning procedure. Check and lean the throttle body.

      The fuel pump supplies high pressure fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel pump module. The function of the venturi pump is to fill the fuel pump module reservoir. The fuel pressure regulator, a part of the fuel pump module, maintains the correct fuel pressure to the fuel injection system. The fuel pump module contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail, in order to prevent long cranking times.

      Check out a technical service bulletin (TSB) regarding issues with starting, stalling and performance. To find it, select “TSBs” in your ChiltonDIY subscription for the 2006 Chevrolet Cobalt. Yikes! there are 700 TSBs currently for the Cobalt! You can go through them one by one or save time by filtering. In the upper left, “Advanced Filters,” select the symptom, “Engine Extended Cranking or Hard Starting Condition.” Check out the gasoline-related TSB as well as the others.

  7. Alexia says:

    I have a 2002 Chevy cavalier, abs it won’t start. I’ve had the car three yrs, it’s a high mileage vehicle, but this is the first time it’s ever given any engine problems. Recently, I had the radiator, water pump, and thermostat replaced.. It does have a pan and valve leak, it’s slow.. I’m thinking its either the fuel pump or starter???

    • ChiltonDIY says:

      Well if it is the starter most times the starter will make a click sound or just not turn the motor over. If the motor will not crank over it could be the starter.

      Have the battery tested and clean all the connections. Make sure there is battery voltage at the starter solenoid and the ignition switch feed wire.

      Test the fuel system pressure. The fuel pressure should read within specifications for the engine in your Cavalier, either the 2.2L engine or the 2.4L engine. Correct fuel pump pressure specifications and more are in your ChiltonDIY subscription for your 2002 Chevrolet Cavalier.

  8. Renee says:

    I have a 2008 Grand Prix and it’s drinking gas.It stalls out and missing bad.

  9. ChiltonDIY says:

    Renee, you will need to scan the Grand Prix for diagnostic trouble codes (DTCs). This may help point us in the right direction. We need to find out what system is malfunctioning and causing the problem.
    Do a basic inspection of the air filter and intake hoses. Make sure the air filter is clean and has no restrictions.
    How are the spark plugs and ignition wires? Have you had your spark plugs changed? General Motors recommends replacing the spark plugs in the 2008 Grand Prix at 100,000 miles. Usually by that time the ignition wires are also ready for replacement.
    What size engine do you have in the 2008 Pontiac Grand Prix? If you don’t know, it is in the vehicle identification or VIN number. The eighth digit tells what engine the 2008 Grand Prix was originally equipped with. If the eighth digit is a “2,” then it was equipped with a 3.8L V6 engine, if the eighth digit is a “C,” then it was equipped with the 5.3L V8 engine. (If needed, please see the response above to Andrew on Jan. 13, 2015 for a picture and explanation of where to find the VIN number.)
    There is a technical service bulletin (TSB) that applies. TSBs are issued by carmakers when they are aware of an issue that they want to notify their dealers and dealer technicians about. If the issue is serious, they recall the vehicles, asking owners to bring the vehicles to the dealer to be repaired or serviced.
    To find the TSB related to stalling, select “TSBs” in your ChiltonDIY subscription for the 2008 Grand Prix. You’ll see a list of more than 550 bulletins. Filter the results by selecting “Engine Stalls” in the “symptom” section. The first two TSBs apply. The third is an important Safety Recall for the ignition key. If you haven’t had this work performed, call your dealer as soon as possible. The dealer will correct the issue at no charge. For your safety, the dealer may ask you to remove other keys from your key ring until you can have the work performed.

  10. Don says:

    I have a 1997 blazer 4.3L. I was driving it the other day and it started to run rough, I thought the gas gauge wasnt reading correctly so I pulled into a station. After putting about $10 in I started it and it seemed to be running better until I started driving. It stalled out on the highway and I had to get a tow. I got it to my shop and started reading the engine codes. It said the crank sensor and can sensor were bad so I replaced them. It started up but ran terribly so I started to read the fuel pressure. The pressure is at 50+ psi but when I start it it just runs like a massive misfire. Everything seems to be like its a fuel pump except for the pressure being fine. Any ideas?

    • ChiltonDIY says:

      Don,
      You should perform the Crankshaft Position System Variation relearn procedure on your Blazer, then retest your fuel system — 50 psi won’t cut it. 50 psi is borderline, it may start but it is not enough to run it.
      Monitor your fuel pressure with the fuel pump running. It should measure within the specified value for your 4.3L Blazer with sequential fuel injection (SFI). Check out the Fuel System Pressure Test explanation, procedure, and correct specification in your ChiltonDIY at PATH: Diagnostics > Diagnostic Routines > Powertrain > Engine Controls – 4.3L > Fuel System Pressure Test.
      You could have a weak fuel pump, clogged fuel system, leaking fuel pressure regulator, or a faulty injector spider. I would take a close look at the fuel system.
      Crankshaft Position System Variation Learning Procedure:
      1. Install the scan tool.
      2. Apply the vehicle’s parking brake.
      3. Block the drive wheels.
      4. Close the hood.
      5. Place the vehicle’s transmission in Park (automatic) or Neutral (manual).
      6. Idle the engine until the coolant temperature reaches 65°C (150°F).
      7. Turn OFF all the accessories.
      8. Enable the Crankshaft Position System Variation Learn Procedure with the scan tool.
      Important: After the ignition switch is turned to the CRANK position, the vehicle control module (VCM) must detect a change in the state of brake switch (from released to applied) in order to run the learn procedure.
      Also, the service brakes, not the parking brake, must be held throughout the duration of the learn procedure.
      9. Apply and hold the service brakes.
      Important: While the learn procedure is in progress, release the throttle immediately when the engine starts to decelerate. The engine control is returned to the operator and the engine will respond to throttle position after the learn procedure is complete.
      10. Slowly raise the engine speed to 4000 rpm.
      11. Immediately release the throttle when the engine speed decreases.
      12. Turn OFF the ignition for 15 seconds after the learn procedure is completed successfully.

  11. tre says:

    Hi, My 2000 plymouth neon started chugging or studdering out of no where, also after that my check engine light and my oil light started comming on and off. My batter never holds a charge for that long either, do u think that it could be a bad fuel pump

    • ChiltonDIY says:

      Hi Tre!
      No, I would have the battery, the battery connections, and the charging system checked before you jump to the fuel pump.
      Then scan the Neon for any diagnostic trouble codes (DTCs), that may help in figuring out the problem. It could be a vacuum leak or faulty manifold absolute pressure (MAP) sensor signal.

  12. Pam says:

    I have a 2004 Sub Impreza, non-turbo, with about 224k miles. Get all the regular maintenance, etc. Got gas yesterday morning, full tank, everything was fine but this morning it turned on then immediately died. That is, it turned over, everything came on, then died. Tried even pumping the gas once and starting it in different gears i.e., 1st then 2d. Same thing, started up and died. It’s almost time for a tune-up within 10k miles, but don’t know if that is the problem or a fuel pump. Any ideas?

    • ChiltonDIY says:

      Hi Pam!
      Well, first check the fuel system pressure with a fuel pressure gauge. It should be within specifications. (Correct specs are in your ChiltonDIY subscription following this path from the navigation tree: PATH: Engine Mechanical > Specifications > Gasoline Engine Tune-Up Specifications).
      Do you hear the fuel pump run?
      Try this, remove the intake hose and spray a small amount of carburetor cleaner or ether into the throttle body. If it tries to start then you may have a faulty fuel system.
      Other things to consider are the ignition spark and timing.
      Have you tried scanning your Subaru for diagnostic trouble codes (DTCs)? I would scan the Impreza, and check both the camshaft sensor and crankshaft sensor signals.

  13. Linda says:

    i have a 01 ford escape and it`s drivin me crazy i was told it was the fuel pump wont`s kick in i hear no sound coming from the tank please help i hate being stuck at home

    • ChiltonDIY says:

      Linda, try hitting the fuel tank with a rubber mallet while someone tries to start the engine. Use caution and good sense when striking the tank. Sometimes you can activate the fuel pump motor to run again — that’s if it is the fuel pump causing the problem.
      Have you checked the inertia fuel shutoff (IFS) switch? This switch shuts off the fuel pump in the event of an accident. It is located behind the passenger’s cowl side trim panel. Check the reset button at the top of the switch. Push on the button to make sure it has not tripped.
      Also, check the fuel pump relay in the fuse block.
      You can always spray s little carburetor cleaner or ether into the throttle body. If it tries to start its fuel related.

Leave a Reply