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!

614 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.

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