How To Tell If Your Fuel Pump Needs Replacing

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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!

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

  1. Brett says:

    I have a 1996 chevy 1 ton van with 5.7 V8. It is hard starting and wants to stall until it reaches temperature.
    I checked the gas line and the return line. Its getting plenty of fuel and the return is clear. All plug gaps wires, cap, and rotor clear. EGR also clear. I was told to rebuild throttle body. Also when running I have to hold the pedal slightly to run smooth without stalling until it reaches temp. I looked down the throttle body and it appears that it is not properly ionizing the fuel.Is it flooding itself? Please advise. ( Brett )

  2. 3d says:

    Sounds like maybe your Fuel Pump Relay (hard starts).
    My 91 chevy has ICM under Coils, this can be removed and tested at Oriellys. Check engine light ? codes?

  3. ChiltonDIY says:

    Hi Brett,

    I apologize for the late reply. I didn’t see your question.

    I would check the idle air control valve (IAC).

    The IAC controls the amount of air needed to run the vehicle, on cold starts, idle, and under engine loads, such as the air conditioner.

    Also take a look at the coolant temperature sensor. Try scanning the van for diagnostic trouble codes, this may help pin down your problem.

  4. Leo Kolodziejski says:

    I have to turn the key 5 to 6 times before my van starts when it sits over night and over the weekend it seems to take forever to start but once it start I really don’ t have any problem starting the rest of the day what could it be I have a 2000 Chevy express 2500 5.7

    • ChiltonDIY says:

      Hi Leo.
      Sounds like a bad fuel pressure regulator. The fuel system should stay pressurized; if it leaks off overnight the fuel pressure regulator could be faulty. Install a fuel pressure gauge, start the vehicle and note the pressure reading. Turn off the engine and let the vehicle sit with the gauge installed, for a few hours. If the pressure drops more than 5 psi there is a leak in the system. It could be a faulty regulator.
      You might have to remove the upper intake to access your regulator.

  5. Gerald Huckleberry says:

    Have a 95 Linc. twn car. Have put 3 new fuel pumps on it. Car is not run that often and it always start right up when pump is first put on. Will stop starting in about 2 months. Cannot hear fuel pump after that. Odds are that there is not 3 bad pumps in a row. Is there a switch that shuts pump off when ignition is off? Is there a wiring harness coupled with other wiring for the pump?

    • ChiltonDIY says:

      Gerald, I would not think that three fuel pumps are defective! Have you checked the fuel pump relay? It could be defective and sticking.
      Check the inertia switch that is located in your truck. If the inertia switch and/or connector is bad it could cause the problem you describe.
      Also take a close look at the fuel pump harness connector at the fuel tank. I have seen a few faulty harness connectors, they overheat due to faulty connections. Inspect the connectors thoroughly!

  6. Gracie Newell says:

    Ihave an 88 iroc it is hard to start and when i stomp on it it acts like it is out of fuel

  7. owen says:

    my car engine is stammering when I start the car and sometimes I have to turn on the key 3 times before it start.

  8. Tony Gonzales says:

    I have a 1998 Ford Ranger Pick-up 4.0L V-6 engine with 225,000 miles on it that has run great. For some time I noticed a slight hesitation on the highway when I would accelerate then it would increase in speed and be OK. It had been starting kind of hard lately, with some sputtering, as well.

    Recently, I made a 600 mile trip and it ran fine, except for the hesitation I described above. One day later, I went to start it in the morning. It started and ran for a few seconds then shut down abruptly. The engine turned but did not want to start again. Later that day I tried to start it again. It started right away and ran at a high RPM then shut down abruptly again. Now the engine turns, but will not start at all. Did my fuel pump go out or could it be an electrical problem?

    • ChiltonDIY says:

      Hi Tony, if you suspect the fuel system, then perform a fuel pressure test. Install a fuel pressure gauge on the fuel rail at the test port. Make sure you have the correct fuel pressure for your 1998 Ranger pickup 4.0L: 56-72 psi.
      Check the fuel pressure regulator operation. The fuel pressure regulator is located on the fuel rail. Is the fuel filter okay?
      Check out the technical service bulletin (TSB) for the wiring harness. This issue can also cause some of the issues your Ranger is exhibiting.

  9. Hannah says:

    I have a 1999 Dodge Dakota 3.9L. I have replaced the IAC three times, and it still wont idle and dies until to temp (have to keep foot on the gas). I’ve learned to deal with it, but three times?!?! New problem, now it wont start. It sputters, shakes, etc. I’m thinking fuel pump. Now that I think about it, recently when it DID start, I would give it gas, and it seemed to do nothing at times. Any ideas on the IAC? And I do hear SOMETHING buzz when I turn the key to on…

    • ChiltonDIY says:

      Hi Hannah!
      It sounds like a faulty fuel pump regulator. The Dodge Dakota’s fuel pressure regulator is part of the fuel pump module in your fuel tank. If your fuel pressure drops off it will cause hard starting conditions.
      Install a fuel gauge on your vehicle. The fuel system should read 44-54 psi with the engine idling. Turn off the engine and then watch the fuel pressure gauge make sure it does not drop more than 10 psi, if it does you have a faulty regulator. Replace the fuel pump assembly.
      There is also a technical service bulletin (TSB) about the idle air control valve (IAC). Check it out in your ChiltonDIY subscription.

  10. Shenay Sanchez says:

    Hello,
    I have a 96 Mercury Sable sedan, just the basic, and I have recently replaced the battery, and after driving for a month, I allowed the car to sit one whole day without driving it, and it was completely dead, had the battery checked, its good…have replaced the relay for the alternator etc…what could this be? Also, may not have anything to do with it, but whenever my car does run I turn the heater on and the door locks lock and unlock automatically as I am driving, or even sitting idle…thank you in advance

    • ChiltonDIY says:

      Hi Shenay, what you are describing sounds like slow draw on the battery.
      Have you checked the generic electronic module (GEM)? Scan the Sable for diagnostic trouble codes (DTCs) that may be stored in the system. The GEM constantly monitors its inputs for concerns. If a concern is found in one of the input systems, the GEM will record the concern as a DTC. The ignition switch position is very important to the GEM functionality. Erratic or unexpected GEM functions can often be traced to problems with GEM inputs such as the ignition switch position, as well as the systems below:

        windshield wipers
        courtesy lamps
        warning chimes
        keyless entry (power door lock)
        interior and exterior lamps
        power windows
  11. Stacy says:

    I have a 2008 Mitsubishi Galant Es 2.4 4 cylinder it is not wanting to start when I turn it to auxiliary I hear a tick tick tick noise and then it won’t fire. I was told it was the battery and jumped it which has worked but I have had the battery tested and it is fine and so is the alternator. Do you think it could be the fuel pump. It runs fine and for long periods of time once it starts.

  12. Tony Gonzales says:

    Thanks for the info on my 1998 Ford Ranger.
    The fuel filter hasn’t been changed since 2008. Could it be plugged up and keep the engine from starting?

    Forgot to mention that after it quit running the first time, I installed new plugs and wires. The plugs were pretty worn out, yet it still ran pretty good, except that it was starting kind of hard after one or two tries.

    After I installed new plugs and wires, I tried to start it. It started immediately for about five seconds at a high rev, then it just shut down and didn’t want to start again after that. All it does is turn and turn but does not fire up.

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