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!

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

  1. David says:

    Hi there I have a 93 Toyota v6 4×4 ,
    The truck ran fine until a week ago it just didn’t run any more.. It has ingnition, i fuel at the fuel rail for the injectors,and of course air. If I where to squirt starting fluid into the intake the truck starts up fine but then dies out. I checked for blown fuses but everything seems to be perfect.
    Not sure what to do next.

    • ChiltonDIY says:

      Hi David.
      Have you checked the actual fuel pressure with a gauge? Make sure it is within specifications. You will find the specification in your ChiltonDIY by following this PATH: Engine Mechanical > Specifications > Gasoline Engine Tune-Up Specifications. The engine should be running while measuring the fuel pressure for this specification.
      Learn more about the fuel system and fuel pump specification for your truck here, PATH: Fuel Systems > Gasoline Fuel Injection System > Description & Operation.
      Do you have any diagnostic trouble codes (DTCs) stored in your truck’s ECM (engine control module)? I would check as this information can be very helpful.
      Did the vehicle shut off while driving or just would not start one day?

  2. Kevan says:

    I have had a recurring issue lately where my car will not start until I charge the battery for 15-30 minutes. I have replaced the battery but it did not help. At first these events seemed to linked to cold mornings (<0°F) but it has done it again recently and the overnight lows were in the 30's. The last time I noticed it happened the fuel gauge was at 1/4 or lower. Is there any connection to low tank level causing the fuel pump to draw down the battery?

    • ChiltonDIY says:

      Kevan, the only thing I can think of, is a 1993 GM car I had in my shop. The oil pressure switch was stuck, so the fuel pump ran all night and would drain the battery. The fuel pump relay would energize the fuel pump and once the oil pressure was up, the command switched and would be controlled by the oil pressure signal. Well it had great oil pressure when the vehicle was off, according to the signal! But a dead battery.
      I would slow charge your battery, bring the battery temperature and charge up. Then check the charging system. Have your battery load tested! Even though a battery is new it can still be faulty.
      Finally, check for a draw on your battery.

  3. Jesse says:

    I have a 1993 Jeep Wrangler with the 4.0l, last summer my fuel pump became intermittent, I replaced the pump with another Carter (the last one lasted two years), however this pump was pretty much bad from the box and replaced it with a Bosch, this pump has been a little louder then the others, but the vehicle ran fan, however when I drove high up in elevation 8000-9000+ last fall my fuel pump became VERY loud, when I got back down to around 4800 the hum had quieted down noticeably. Today when I went out driving around 6000′ in elevation about 50 miles into my trip my fuel pump started getting loud once again and another 50 miles later back down to 4800′ jn elevation my pump was VERY loud. I’m not sure what this could possibly be, I replaced my fuel filter when I did my pump, I also checked my fuel pressure regulator with a vacuum line at the time and it held pressure. I’m not sure what it could be?

    • ChiltonDIY says:

      Hi Jesse.
      Altitudes at which a pump is operated will enhance or diminish its performance. At higher elevations atmospheric pressure is decreased, reducing suction. Altitude affects engine performance as well. A rule of thumb is that gasoline and diesel engines will lose 3% of their power for every 1,000 feet of elevation. This is due to the lack of oxygen at higher altitudes. The fuel pump works harder and is usually noisier.
      This is a normal condition. The addition of a second external fuel pump can help.

      • Jesse says:

        Okay, however I haven’t had this problem with other fuel pumps in the Jeep. To me something is not adjusting correctly and making the fuel pump work harder then it should. Could this be a fuel pressure regulator problem?

        • ChiltonDIY says:

          Hi Jesse.
          The continued problem could be a result of the fuel pressure regulator making the pump work harder, but not likely, my guess is that it’s a problem with the aftermarket pump. Are there any codes set indicating low fuel pressure?

          • Jesse says:

            No there is not, it’s an OBD1. My jeep doesn’t act like it is having a low fuel pressure problem, the motor has it’s normal power. But like I have said it only gets loud when I’m In high altitude, after I come back down to my normal level, it’s quiet, sometimes it has to sit for an hour or two for something to reset and be it’s normal quiet pump.

  4. dexter says:

    I have a 1988 k5 with 350 good wrench well the truck takes longer to start will ideal fine but when it Is put into gear it will stall out, but the problem started with trying to go up a hill and it shut off

    • ChiltonDIY says:

      Dexter, it sounds like an air/fuel problem. I would check the truck for vacuum leaks.
      Also, scan the truck for diagnostic trouble codes (DTCs). Is code 44 present — 02 circuit (Lean condition)?
      Check the fuel filters.
      Perform a fuel pressure test, it should read 9-13 psi with a 13 psi minimum deadhead pressure.
      Check the TBI (throttle body) gasket.

  5. Kyle says:

    I have a 99 Mazda 626 (automatic) and in the past year it has stalled out on 3 separate occasions after coming to a stop at a stoplight. After letting it sit for several hours, the car will start up again without any problem like nothing was wrong. I even had the car towed to a mechanic after one of these instances. The car was towed to the shop on a Saturday and on Monday when the mechanic went to see what was wrong, the car started up fine and showed no signs of an issue. Is it time to buy a new fuel pump?

    • ChiltonDIY says:

      Kyle, your engine has sensors that could cause the issues you are experiencing with your car. Don’t jump the gun and replace your fuel pump. Sometimes a crankshaft position sensor can cause the problem. I had a vehicle for a week until I found the crankshaft position sensor was faulty. It would not set a diagnostic code. It would happen after the engine warmed up. After the engine cooled down it would start up and run fine.
      Did the shop actually check the fuel pump pressure? Did they scan your 626 for diagnostic trouble codes (DTCs)? A faulty power or ground connection would erase the codes if they were present. Check the power and ground connections. Make sure your battery is okay while you are checking the power supply, batteries have been known to cause crazy problems.

  6. cody says:

    I have a 192 ford f-250 super duty I have to turn the key on and off three times before it will start what should I do? do I replace the fuel pump

    • ChiltonDIY says:

      Hi Cody.
      Check the fuel pressure and the fuel pressure regulator. Does the truck run okay after it starts? You
      could have a problem with the idle circuit. Have you scanned for any diagnostic trouble codes (DTCs) in your truck?
      What engine do you have in your truck and is the year 1992?

  7. Gaylen says:

    My 1988 Buick Century 3.8L has a consistent pressure of just under 30Lb. When I remove the vacuum line from the regulator it increases by 10Lb’s. When the care is all put together it has poor acceleration to drive, and in park it falters at higher RPM’s. But when I pull the vacuum line off it is better. Also the idle is slightly rough then better when I remove the regulator vacuum line.

    Thank you for your help.

    • ChiltonDIY says:

      Gaylen, The fuel pressure should read 34-46 psi, sounds like your fuel pressure is a little low.

      Perform a Volume Test: This test should be completed after the pressure test has been performed.
      Disconnect the pressure gauge from the fuel line and connect a flexible tube from the fuel line to an unbreakable container.
      If the engine is equipped with a fuel return line, squeeze off the line to obtain an accurate reading.
      In 15 seconds, the fuel pump should supply at least a half pint of fuel.
      If the fuel volume is below minimum, check the fuel line for restrictions (fuel filter).
      After testing, reconnect the fuel line.

      • Gaylen says:

        I misunderstood your instructions but I did get some data. Pressure is 29 Lbs from the shrader valve. When the vacuum line is removed from the regulator the pressure moves (basically jumps) to 39 Lbs. The volume (from shrader valve) was greater then 1/2 pint in 15 seconds this was done without the return line from the bottom of the regulator pinched. I got a little more then 1.5 cups. I pinched the return line and the fuel pressure did nothing when I released it the pressure vacillated but returned to a stable 39Lbs. I left the line pinched for about 5 minutes and the car died. Does this help you to help me?

        Thank you for your time,
        Gaylen

        • Gaylen says:

          Also the car died in 16 seconds when I checked the volume.

          • ChiltonDIY says:

            Gaylen, what is the 8th number of your VIN? The fuel pressures are different.
            VIN # 3 Fuel pressure 34-40
            VIN # C Fuel pressure 40-47
            Dead head pressure should be at least 75 psi (blocking off the fuel return line).
            The VIN is located on the driver’s side of the dash.
            Have you scanned the Century for diagnostic trouble codes (DTCs?

          • Gaylen says:

            The VIN’s 8th position is a “3″. I did not get a pressure reading of 75 PSI when I pinched the return line. there was basically no change. the needle did vibrate for a time when I unstopped the return line. What I need to know, based on the data I have presented, is your opinion about weather or not there could be a problem with the regulator or the pump or perhaps something else. I am not getting any DTCs.

            Thank you for your time.

            • ChiltonDIY says:

              Gaylen, have there been any tune ups in the recent past?
              Did you verify the ignition system for proper spark and that the firing order is correct?
              One can easily misroute the spark plug wires on this engine and this can cause the vehicle not to run properly with similar driveability symptoms.

          • Gaylen says:

            I replaced the plugs and wires and the Crankshaft position sensor. I did check the firing order but I will check again.

            If you read the whole thread you will notice that the care runs better when the vacuum line is removed from the fuel pressure regulator and the hesitation is greatly diminished at high RPM’s. Also the pressure increases by 10 psi.

            Thank you.

            • ChiltonDIY says:

              Gaylen, it sounds like the fuel pump pulsator or hose may have come loose. This can cause the fuel pump pressure to leak around the pulsator or hose connections. You would feel it under severe acceleration.
              If the fuel pump has a leaking pulsator remove it. Install a small piece of rubber fuel line with small hose clamps.
              We have seen pulsators leak, and we would just install a hose connection. You can purchase a new pulsator for approximately $28 dollars. The pulsator is just a dampener that has no effect on anything as far as engine performance goes.

          • Gaylen says:

            Thank you.

            • ChiltonDIY says:

              You are welcome Gaylen :)

              • Gaylen says:

                My son and I were discussing your answer, and he said “if it is unnecessary how is it the problem?” So just to be clear can you answer this. Also in case I was not clear; with the car not under load I can push the accelerator past the sputter but it is never running quit right.

                Thanks.

              • ChiltonDIY says:

                Hi Gaylen.

                The fuel pump pulsator sits inside the tank on the fuel pump. There are no clamps holding it on. The fuel pump pulsator has O-ring seals which will leak at the connection between the pump and the fuel supply line. That means it will leak off if the vehicle sits for an extended period of time. Or it will leak while driving causing low fuel pressure.

                If you want to check for this condition, leave the fuel pressure gauge installed when driving and after the vehicle has been turned off. Look for problems with the pressure.

  8. Itcel says:

    Hi I have a 2000 year chevy cavalier Ls and I had a mechanic look at it. Says my car needs a new fuel pump. The reason is. Ecause my car starts but dies right away. How much is it for the pump and change?

    • ChiltonDIY says:

      Hi Itcel.
      A fuel pump assembly for your Cavalier can run $180.00, some cost more and some are less.
      Make sure you purchase a quality pump with a direct fit. Some pumps can be removed from the module and will be 100.00 dollars cheaper. The labor time to remove the tank and install a pump is 2.0 hours labor. That does not include diagnostics! (Diagnostics includes testing and troubleshooting to determine the cause of the problem and the appropriate repair.)

  9. Rachel says:

    I have a 97 Mercury Tracer. One night when I was getting ready to go to work, I started it to defog the windows (had been raining) and after about 5 minutes of running it started chugging. The next day it was fine until I went to come home from my second job and about halfway through a 10 minute drive it started chugging, stalling, and dying. I changed the fuel filter and the idle air control sensor (hooked it up to a computer and it came back with the code for IAC). Again today, it got me to work fine but started chugging and dying again. Could this be my fuel pump? I’m running out of ideas.

    • Rachel says:

      Also, when I changed the fuel filter and it didn’t fix the problem, the reason I called for a computer/code reader was because it would be fine cold, and then it would rev to almost 3000 rmps then bottom out at less than 500 repeatedly and in quick succession before dying.

      • ChiltonDIY says:

        Hi Rachel.
        How many miles does the Tracer have? It sounds like an oxygen sensor problem. Oxygen sensors are good for about 75,000 miles. I’ve seen first-hand that a bad oxygen sensor can cause these symptoms without setting a diagnostic trouble code.

  10. nark says:

    Had altenator changed in 2004 maxima but I started car nd it shut off right away whats the problem

    • ChiltonDIY says:

      Hi there.
      I would check the battery and connections. Have the battery completely recharged, and checked out.
      A faulty battery can cause the engine to shut down.
      Once you have verified the battery is okay, check the alternator output. Remanufactured alternators can be faulty, right out of the box. If you install an alternator and you don’t recharge the battery, you can overload the alternator’s output causing premature failure.
      Make sure all you connections are clean and tight at the battery and the alternator.

  11. nefi says:

    I have a 96 chevy blazer and I think the fuel pump is going bad it stutters and sometimes it wouldn’t start I had to bang on the gas tank underneath and it would want to start. it has 186,000 miles on it and it has had the fuel pump replaced once about six months into it the new pump it started doing it again, can it be something else or could it be the fuel pump again?

    • ChiltonDIY says:

      Hi Nefi.
      Yes new fuel pumps can go bad. Was the fuel pump expensive, or an economy pump?
      I have seen a few problems with economy fuel pumps. The fact that you bang on the tank and
      it starts, makes me think something is wrong with the fuel pump or the connections.
      Try re-checking the pump and connections. Have you scanned the Blazer for diagnostic trouble codes (DTCs)?

  12. my daughter bought a chevy Malibu and ever since she got it on hot days it cuts off. There are no codes showing and we heard a hissing sound and my husband dropped tank and found the round thing on top of tank(im not sure what its called) was not in the hole a locked by the spring so he fixed that and it seems to have made cutoffs more frequent. it only does this when its hot outside, where should we start to try and make it reliable, it has cut off in a curve 2 times on her with my grandchildren in the car im very afraid but she has to have way to go for the children when I can’t take her..please help

  13. M Sakr says:

    I have a Volvo S60 and every time I start the engine its stutters and sometimes wouldn’t start at all.

    The thing is, it does this when the car was not started before for a long time (over night or for a few hours). If I stop the car and restart it, it starts fine.

    Could this be the fuel pump? Or maybe the battery?

    Thanks

    • ChiltonDIY says:

      Hi there.
      If the Volvo has a long cranking time after it sits for more than 1 hour, it very well could be the fuel pump.
      After you turn the vehicle off it should hold fuel pressure at the fuel rail. If the pressure drops off then you might have a faulty fuel pump.
      Install a fuel pressure gauge and check to see if it holds fuel pressure.
      The battery should be okay if the vehicle’s engine is turning over.

      What year is the S60?

  14. Jen White says:

    I was driving and my car started losing speed, so I pulled over and the car cut off. I Tryed to start the car several times, then maybe after the forth try it started poorly but I was able to make it home which was a mile away. Could this be a fuel pump issue?

    • ChiltonDIY says:

      Yes it could be, Jen. How did the car run after you made it back home? Have you tried starting it again?
      I need more information about the car, what is the make, model, year, and engine size?
      If you don’t know what engine it has, the 8th digit of the VIN number identifies the engine the car was originally equipped with. If you think the original engine is still in the car, what is the 8th digit of the car’s VIN? (The VIN is 17 digits long and is on your car insurance and the title or registration; it is also stamped on a plate affixed to your car, usually visible from the outside the front windshield looking in to the passenger side dashboard.)

  15. Rell240 says:

    Hey I have a 89 nissan 240sx and yesterday I ran into a problem, I parked my car an shut it off and when I went to turn it back on it didn’t start, the car was on electrical wise but there was no starter flicking or any feed back from the car starting. I pushed to start and drove home. When I got home the car turned on and off fine. Today I get into the car to go to work and get stuck at a gas station. Once again the car dosent start up. Once I pushed to start again at high rpm the car would putter and lose flow like it nearly stalled out as I was driving. I say idle and it shut off. Got the car to start again and made it home. So what is this? Fuel pump? A mechanic told me it can be a number of things but this guy has ripped me before so I would like to find the problem before hand. Much appreciated!

    • ChiltonDIY says:

      Hi there.
      First have the battery and alternator checked out. A faulty battery or alternator could cause the problems you are experiencing with your 240sx.
      Next check the starter operation. It sounds like something in the starting system.

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