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!

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

  1. My engine in my truck, when sitting for three to eight hour, will not start when turn the ignition on,but will start on the second try and their after, only when it sit’s a long time.

    • ChiltonDIY says:

      Hi Hamp.

      It sounds like a bad fuel pump regulator. Is it a Chrysler product? Install a fuel pressure gauge on the vehicle’s fuel system, and then check the running pressure. Turn of the vehicle off. With the fuel gauge installed check to see if the fuel pressure slowly drops off. If it does you may be dealing with a faulty fuel pressure regulator.

      If you have a leaking injector causing the problem, you will have a fuel smell, blue smoke and a possible misfire when trying to start the vehicle.

  2. John Pineda says:

    I have a Bronco II with a return line issue that causes an internal leak issue. Sounds about the same problem, you have to cycle the Key On Engine Off. You’ll hear the fuel pump working building pressure. Once the pressure is met you will hear a distinct sound out of the norm from the fuel pump letting you know that the pressure is there. At that point the Vehicle with crank over with no problem.

    • ChiltonDIY says:

      Pull the vacuum line off the fuel pressure regulator.
      If the diaphragm goes bad, fuel will be sucked into the vacuum hose, directly into the intake. Usually this will cause a rich running condition and hard starts.

  3. Tim Lintemut says:

    I have a 99 chevy blazer. Thought tranny was going bad. Now after reading I am not so sure. Problem is intermittant, can not find common denominator. May go a week may act up daily. Highway speed surges about 200 rpms. cruising at 70mphs, maybe up a hill but honestly not always… From a stop moving out of first to shift to second (automatic)chugs and starves it seems to starve for fuel. Always felt it wanted me to put foot in gas. Does not do it at all if I manually shift into “2” then move it to 3 at 30mph but even in 3 she seems to have this surge or hesitation… been doing it for 8 months…took to tranny shop, she was not acting up that day, computer said no problem. No codes being lit up on dash..Fuel filter changed, MAF cleaned, Air filter changed, TPS changed, cap and rotor changed, left with either vacuum leak, tranny issue, plugs, or …..Fuel pump Any thoughts?

    • ChiltonDIY says:

      Hi Tim.
      Check the spark plugs. Carbon tracking on the spark plugs could cause a misfire.
      Check the EGR valve, if the pintle sticks this could cause a hesitation.
      And last but not least check the fuel pressure. You’ll find the correct specification for your Blazer and the fuel pump it was equipped with at ChiltonDIY.

  4. josh patterson says:

    i have a 95 impala ss. when i put it in gear and give it gas it stumbles and cut off. but if i don’t give it gas its fine. why is this problem happing?

    • ChiltonDIY says:

      Hi Josh. Well it could be a number of problems. Check all the basics and scan for trouble codes. It sounds like a lean condition.

      Basics:

      Spark plugs
      Spark plug wires (ignition cables)
      Air filter
      Fuel filter
      Vacuum leaks
      Fuel pressure

      • josh patterson says:

        i got it fixed!! my fuel filter was clogged up spark plugs were the wrong ones (that caused it to back fire) my EGR was stuck closed and my fuel pressure regulator was no good

  5. Salina Fernandez says:

    I have a 2006 Chevy Equinox. For the past couple of months it would take two or three turns of the key to start and the other day I was at a red light and my car just shut off. it cranks but wont start. is it the fuel pump?

    • ChiltonDIY says:

      Salina, I would suspect the fuel system. When you turn the key on with the engine off, listen for the fuel pump to energize. You could very well have a bad fuel pump.

  6. myra says:

    How do you test if a fuel pump is going bad on a 2005 ford freestar? and where is the fuel pump located at?

    • ChiltonDIY says:

      The fuel pump is in the fuel tank.
      Have you checked the inertia fuel shut off (IFS) switch? It sits behind the jack access cover. If this trips it shuts off the fuel pump. (Reset the IFS switch).
      The fuel pump is controlled by the powertrain control module (PCM). Electrical power to the pump is provided through the IFS switch located in the jack access panel on the right-hand side interior rear quarter panel.
      Turn the Key On Engine off, listen for the fuel pump to energize.
      Install a fuel pressure tester to the fuel rail and check the pressure. Refer to your ChiltonDIY for the correct fuel pressure specification, here’s the navigation path: Engine Mechanical > Specifications > Gasoline Engine Tune-Up Specifications.

  7. amber says:

    I have a 1996 Nissan maxima. a couple days ago i’m driving to work and my car stalls and shuts off while driving. my cars smells heavily of gasoline. so I left my car at work. today I try to go to lunch with my car and I don’t make it out of the parking lot before loosing a 1/4 tank of gas. my exhaust pipe smells of gasoline and my car shakes while running. I have no clue as to what’s happening.

    • ChiltonDIY says:

      Amber, have the car towed to your house or a repair shop! Do not drive it! You may be causing more damage to the engine, not to mention the fire hazard.

      The issue could be a faulty fuel injector.

  8. Molly says:

    I have a 1996 chevy s-10 6cyl. As I was driving on the highway today I noticed that my truck seemed to be slowing down as if I let my foot off the accelerator. If I pushed the accelerator down it would pick up speed again. As I paid more attention I made sure it wasn’t me letting off the gas. Later I noticed the same thing in town. If I gave it more gas it would be ok, but if I didn’t push the accelerator down more the truck would start to buck. I had the fuel filter changed and this didn’t make a difference. My dad thinks it might be the fuel pump.

    • ChiltonDIY says:

      Hi Molly.

      There is a Technical Service Bulletin (TSB) that may apply to your situation. General Motors identified a situation that can occur called: “Intermittent engine low power, hesitation, and/or stall.” It is #66-65-06.

      When you subscribe at http://www.ChiltonDIY.com you can access the Technical Service Bulletins and Recalls that apply to your Chevy S10, as well as maintenance interval charts, specifications, and service and repair procedures. Your automotive technician will also have access to Technical Service Bulletins.

  9. Jazmine says:

    01 Chevy Blazer- I have problems starting it when it’s lower than a quarter tank, but eventually does. It will stall on the freeway and I have to pump the gas pedal. I think it could be fuel pump but I’ve also heard it could be the alternator…?

    • ChiltonDIY says:

      Hi Jazmine.

      Any time the vehicle stalls out on the road it can be dangerous; repair the vehicle asap.

      Check the fuel pump pressure and the fuel pump relay connection. Scan the vehicle for trouble codes. Due to the fact it acts up with less than a 1/4 tank makes me think it is fuel related.

      TSB #04-08-49-018E may apply.

      What’s a TSB? Technical Service Bulletins, or TSBs are communications from the original equipment maker (OEM). For your Chevy Blazer, it is General Motors Corp. In this case, General Motors identified a concern related to the fuel sensor and issued a bulletin. Technical Service Bulletins and Recalls are provided for your vehicle, along with service and repair procedures when you subscribe to http://www.ChiltonDIY.com.

  10. joshua wilkins says:

    My 2007 toyota solara starts up normal and shakes and cuts off after seconds.. I needed oil so I put 2 quartz in and now when I crank it up it does the same but if I try to hurry up and drive it stalls and won’t go full speed and if I make a complete stop it’ll shake and cut off.. I have 60, 000 miles on it

    • ChiltonDIY says:

      Hi Josh! Check all the basics, air filter, plugs, vacuum leaks. It could be a mass air flow sensor, throttle position sensor, or a dirty or binding throttle body. Install a scan tool and check for diagnostic codes.

  11. marie says:

    My car starts fine, it is during the process of driving and stopping that it might cut off. At times it takes at least 15 minutes to restart it. I think i got gas with water in it and it jerks while driving to the point of cutting off. Dignostics show no problems, but i think its my fuel pump going bad.

  12. meo says:

    I have a 2001 Saab 9.5 aero,turbo engine.my symptoms at first were random short periods of time the car wouldn’t turn over.I’d have to let the car sit for about 5 minutes to even an hour then after several tries it would finally start.The car would drive great for days and then eventually the same problem would reoccur.It wasnt until recently the car just started stalling out while in operation,then again sitting for about 5 minutes to even an hour it would start back up. yesterday I ran an errand and came back to the car and the car starts but wouldn’t turn over after several tries an hour and a half later the car turned over for about 5 minutes and stalled out. When trying to restart the car it wouldn’t stay running long enough to do anything. Yesterday was the worst.If I had to describe it any further I’d say it’s very similar to the staking that happens by not having your foot on the clutch when driving stick. But my car is ofcourse an automatic.
    Also I noticed before the stall happens I don’t feel pressure under my gas pedal.

    I hope this makes sense and maybe you can offer so advice as to what maybe going on. Fuel pump maybe?
    Thanks

    • ChiltonDIY says:

      Hi there.

      There is a technical service bulletin (TSB# 248-2473) that describes symptoms similar to what you are describing. Saab sends out a TSB when it identifies an issue that affects a number of vehicles.

      This TSB also explains the need for a scan tool, which will help diagnose the problem. The vehicle needs to be scanned to see what has been going on.

      Coincidentally, the last Saab I worked on did have a bad ignition module, as described in the TSB.

      Expert diagnosis is the way to determine the cause, as it may be the ignition module or something else.

      With a subscription to the 2001 Saab 9.5 information at http://www.ChiltonDIY.com you can access the TSBs, service and repair procedures and more.

  13. Kegan says:

    I have an 02 mini cooper. Filled up with gas (11gallons) and drove home after work one night. Its 1.7mi to my house from fill up. The car only registered half full on the gauge. Thought that was weird. Tried to start it next morning and it turned over and sounded like it was going to start but didn’t.

    • ChiltonDIY says:

      Hi Kegan. Scan the vehicle for trouble codes. Sounds like the fuel pump and sending unit may be faulty or it has a connection problem. The fuel pump and sending unit are located in the fuel tank.

  14. heather says:

    I have a 98 Chevy Monte Carlo 3.7L. I have to give her gas when I turn her on and must keep my foot lightly on the gas pedal at all times. Sometimes she will just stop n run normally but just s quickly revert back. Does this sound like a sign of the fuel pump going out? Also if she doesn’t die without my foot on the pedal the rpm’s stay at below 1 and a smell will accompany the rough idle.

    • ChiltonDIY says:

      Hi Heather. Scan the Monte Carlo for trouble codes. It sounds like you have an idle issue. The Idle Air Control (IAC) valve is supposed to adjust the idle. Check for vacuum leaks at the intake manifold and vacuum lines. Clean the throttle body and inspect for carbon build up.

      IAC Description:
      The purpose of the Idle Air Control (IAC) valve is to control engine idle speed, while preventing stalls due to changes in engine load. The IAC valve, mounted in the throttle body, controls bypass air around the throttle plate. By moving a conical valve, known as a pintle, IN (to decrease air flow) or OUT (to increase air flow), a controlled amount of air can move around the throttle plate. If RPM is too low, the PCM will retract the IAC pintle, resulting in more air being bypassed around the throttle plate to increase RPM. If RPM is too high, the PCM will extend the IAC pintle, allowing less air to be bypassed around the throttle plate, decreasing RPM. The IAC pintle moves in small steps, called counts.

      During idle, the PCM calculates the proper position of the IAC pintle based on battery voltage, coolant temperature, engine load and engine RPM. If the RPM drops below a specified value and the throttle plate is closed (throttle position sensor voltage is between 0.20 and 0.74), the PCM senses a near stall condition. The PCM will then calculate a new IAC pintle position to prevent stalls.

      If the IAC valve is disconnected and reconnected with the engine running, the idle RPM will be wrong. In this case, the IAC has to be reset. The IAC resets when the ignition switch is cycled ON then OFF. When servicing the IAC, it should only be disconnected or connected with the ignition switch in the OFF position to keep from having to reset the IAC.

      The position of the IAC pintle affects engine start up and the idle characteristics of the vehicle. If the IAC pintle is open fully, too much air will be allowed into the manifold. This results in high idle speed, along with possible hard starting and a lean air/fuel ratio. DTCs may be set. If the IAC pintle is stuck closed, too little air will be allowed in the manifold. This results in a low idle speed, along with possible hard starting and a rich air/fuel ratio. Another DTC may set. If the IAC pintle is stuck part way open, the idle may be high or low and will not respond to changes in engine load.

  15. Danielle says:

    Hi I have a 2006 pontiac g6. I am having the same problem as the person above, when my car sits for 3 or more hours and I try to start to car it sputters & heistates. Then on the second or sometimes third try it comes on. I have now began to smell fuel. I was told it was the fuel filter but that is located in the fuel pump. I don’t want to send $400.00 bucks on a fuel pump until I know for sure!!! Please help!!!!

    • ChiltonDIY says:

      Hi Danielle. What engine does the G6 have?
      If you smell fuel, the system is either rich (not the fuel pump) or an injector is leaking inside or outside the engine. It could also be misfiring at start up, are the spark plugs okay? Does the vehicle run okay after it warms up? If it misfires it should set the check engine light. Are there any trouble codes present?

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