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!

849 responses to “How To Tell If Your Fuel Pump Needs Replacing”

  1. glen derosier says:

    I have 1993 dodge caravan that died on the road sputters then died.wouldnt start..i suspect fuel pump..or camshaft sensor or throttle body sensor or fuel filter or something to do with fuel system.i put new spark plugs n filter still starts up rough n press gas pedal give gas it dies.ive been trying to figure it out for a what seems to be the real problem its a 3.3 engine..

    • ChiltonDIY says:

      Hello Glen.
      Check the fuel pressure to make sure it is within specification and scan your Caravan for diagnostic trouble codes (DTCs).
      By scanning the Caravan for DTCs it will help pin down your problem. You need to find out whether it is a fuel or spark problem.
      Fuel pump pressure specifications and testing is in your ChiltonDIY subscription for the Caravan, follow this PATH: Fuel Systems > Gasoline Fuel Injection System > Fuel Pump > Testing > 3.0L, 3.3L & 3.8L Engine.

      • Greg says:

        Same stuff happening as above.
        I received two codes. For the crankshaft sensor and for the cam sensor. Both of those are replaced and still having same issues as above. The check engine light comes on when it starts to sputter and misfire. I believe the reason its sputtering and dying and unable to start is fuel related. Spark and air are good. coil pack and plugs were replaced. Fuel relay was replaced. Fuel filter needs replaced but not restricting. Would a bad fuel pump be not giving my car enough fuel to run and fire right?

  2. James Maxwell says:

    This is how I fix mini vans (or fords). Take two sticks of dynamite, place them lit on the road, slowly drive over them, park and get out. Stand at least a hundred feet back. Bingo! Problem solved! Note: this also works on all imports :)

  3. Zach says:

    I have a 93 chevy Cheyenne, the truck has a fluctuating rpm at idle. & only happens at normal operating temp. Any ideas?

    • ChiltonDIY says:

      Hi Zach!
      Wow! That could be caused by a large number of things, from a vacuum leak to a MAP sensor to a fuel pressure problem and more! I suggest that you have the truck scanned to see if a code was set, otherwise it’s a hit or miss thing.

      • Zach says:

        I did have it checked out and my mechanic told me it was either. A fuel pump problem or a o2 sensor. But I’m not sure which way I should go..

        • ChiltonDIY says:

          If the mechanic is correct in his assessment, then each component could be tested. The fuel pump pressure at idle should be tested by the mechanic. Also, the O2 sensor can be tested for fluctuating voltage.
          Since the vehicle is a 1993, I’d assume it has high mileage. If you don’t have the tests done, an O2 sensor is a lot cheaper than a fuel pump. O2 sensors are generally good for about 70,000 miles before they need replacing.
          The first thing I’d check, though would be the throttle position sensor (TPS). Fluctuating idle speed is a hallmark of a bad TPS.

  4. Zach says:

    My mechanic would have check the fuel pressure but there are no ports to use to check. & I suppose he could of checked the 02 sensors. I suspect the o2 sensors are in definite need of change anyway, like you said. & I will also check the tps & get back to you.

    • ChiltonDIY says:

      Zach, which engine does your truck have?

      • tawana says:

        Hello I have a 02 Pontiac montana. Liquid is gushing from the driver side, I put a bucket under to see what kind of fluid it may be, it was reddish watery type fluids and a lot. Someone told me it could be the fuel line, would that mean a new fuel pump as well?

        • ChiltonDIY says:

          Hi Tawana.

          No it sounds like a coolant leak or it is overheating. Refill the radiator and pressure test your cooling system. Make sure the coolant fans work and your thermostat is not stuck.

          GM issued a technical service bulletin TSB) on intake manifold gaskets leaking; it may be the cause of the water leak. The TSB is in your ChiltonDIY subscription for the 2002 Pontiac Montana. The bulletin describes the issue and how to fix it.

  5. eugene says:

    I have a 91 ford explorer, and it will crank and run at first and on=d it wams up and i cut off the ignition, then it will not crank up, the firdt time I do crank it I can hear the fuel pump, but after I cut it off & try to crank it up then it will not crank and I do not hear the fuel pump at all, what could be the problem ? is this an ignition promlem or a fuel system issue? doesit need a a new fuel pressure gauge or a new fuel pump or what eles does it need to be replaced?

    • ChiltonDIY says:

      Hi Eugene.
      I would check the inertia switch, EEC (computer) relay and the fuel pump relay.
      Remove the intake tube at the throttle body and spray a small amount of intake/carburetor cleaner inside. See if the engine tries to start, this will let you know if it is a fuel problem. A fuel pressure gauge set is very helpful in this situation. Don’t forget to check for spark when the vehicle shuts off and will not start. Remember, to start the engine needs to be in time, have compression, fuel and spark.
      The EEC power relay supplies battery voltage to the fuel injection computer, the fuel injectors, the fuel pump relay, and some emissions-related solenoids.
      The fuel pump inertia switch shuts off the fuel pump(s) in case of an accident.

  6. Jean says:

    I have a 1994 Toyota 89,000 the car will start and once I start driving the car will stop is from the fuel pump

  7. johnnie says:

    My car takes a min to start up cranks buy wont start and when get it started it putters out?

  8. Jen says:

    My 93 Chevy truck quit on the road going up a slight hill, it would turn over but not start. Tried to use ether just to test if it wasn’t getting fuel and it still wouldn’t start. Mechanic replaced distributor (it was totally rusted inside) worked fine next day until my way home I hit the gas and it didn’t respond as well as it normally does. But after that it was fine, even going up steep hills. Could it have just been a fluke?

    • ChiltonDIY says:

      Hi Jen.
      Yes it could be a fluke, did the check engine light come on? If it happens again suspect the distributor, Re-manufactured distributors have been known to have problems if they used cheap components and/or the shaft is worn. I always rebuild the distributors myself, to avoid problems.

  9. Dave says:

    I have a 2000 Dodge ram 3.9 v6 magnum. I started it up this afternoon and I’m hearing a loud humming sound coming from the gas tank area. I’m thinking fuel pump?? Any help would be greatly appreciated

    • ChiltonDIY says:

      Hi Dave.
      More than likely it is the fuel pump. There could be a lot of things causing it, from a failing pump motor to temperature. I’ve heard that high ambient temperatures can cause the pump to be unusually noisy, especially when the fuel level is below ½ tank. If adding fuel, which is cooler from the underground tanks, eliminates or lessens the noise, that’s it. In any case the noise could be a sign that the pump is giving out.

  10. Pat says:

    I have an 01 LeSabre that dies while driving. Usually I’m doing about 50 – 60mph. I changed the mass air flow sensor, EGR valve and fuel pressure regulator but im starting to think it’s the fuel pump. One time after it stalled and sat for a few seconds I heard a whirring noise coming from the back end.

    • ChiltonDIY says:

      Hi Pat.
      It could be the fuel pump, but the car definitely needs to be scanned. With that symptom it’s very likely a code was set. Scanning will avoid unnecessary parts replacement.

  11. toye says:

    if a car travel 2 to 3km and the Burnett is hot.
    if the vehicle is hot can it affect the mal-function of the fuel pump..
    what can I do if am experience the above situation…

  12. Khamis says:

    Iam writing from Jordan, I have 1999 SsangYong summo SUV, with Mercedes 2.3 gaz engine, manual gear.
    When start engine and on idle stat, RPM fluctuate under 1000, and while driving power keep goes down as if it needs lower gear, meckanic is suspecting fuel pump, is this ok, Please forgive my english

    • ChiltonDIY says:

      Hi Khamis.
      Are there any diagnostic trouble codes (DTCs) stored in the vehicle’s computer? Sometimes a faulty mass airflow sensor can cause the same problem, check all the intake hoses for leaks or loose clamps. Make sure a fuel pressure test is performed first, so you don’t replace unnecessary parts. Has the fuel filter ever been serviced?

  13. Pete says:

    My 2004 Ford Focus ZTW is having some issues that aren’t setting any codes. While driving or at stop lights, it stutters as if it’s going to shut down multiple times per trip. It’s almost as if it were a manual and I’m not giving enough gas before letting the clutch out. Any ideas here?

  14. Khamis says:

    How to read (DTCs) , intake hoses been ckecked and found ok ,fuel filter been replaced a year ago, will replace mass airflow sensor and report.

    Many Thanks

    • ChiltonDIY says:

      Hi Khamis. You will need a good quality scan tool that is designed to work with your vehicle in order to read the diagnostic trouble codes (DTCs).
      You can try to clean the mass airflow sensor (MAF) before replacing it. Special cleaners are available for the film elements inside the MAF. I always try to clean a faulty MAF first. Sometimes this can work wonders.

  15. Franchele says:

    My car takes a while to start up. first I thought it was the starter , but I got a brand new one and a battery and altenator. im just confused on what else it could be to cause a troubled start

    • ChiltonDIY says:

      Hi Franchele. We need to know what exactly the car is doing. Is it cranking over but no start up? Or no cranking sound and the engine does not turn over?
      And, what is the year, make, and model of the vehicle, please. :)

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