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!

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

  1. bonni says:

    Hi. I recently bought a 1993
    Honda Civic. Two or three times lately (twice today), it started, then stalled, and wouldn’t start again until after five or ten minutes. It seems like it’s idling a little slow, too. Any ideas?

  2. Jafar says:

    I recently purchased a 93 chevy s10 pick up and drove it home 25 miles with no problem. The next day I cranked and repositioned it in my yard with no problem. The following day when I crank it, it fires up fine then the engine starts to stall and it shuts off. It is a 5 speed manual transmission and if I give it gas after I start it, it’ll stay crank and if I throw it into gear quickly I can move, but I must continually give it gas or it’ll shut off. If I had to come to a stop I would have to throw it in neutral and rev the engine to stay cranked instead of letting it idle with no gas like it should. Like the engine is starving for fuel and only gets enough to stay cranked when I hit the pedal and this has me thinking that it’s related to the fuel system. It has a carburetor and I’ve been told that the likely culprit is a bad fuel filter. Does my detailed description help zero down the problem within the fuel system?

    • ChiltonDIY says:

      Hi Jafar. Sounds like you might have a problem with the carburetor, but check the fuel filter first. Is the automatic choke working properly? It should close when the engine is cool and open when the engine warms up.

      Do you smell fuel? Is it running rich or lean? Dark exhaust? Does it backfire? The system is OBD1, are there any diagnostic trouble codes present?

  3. evan says:

    hi,
    i just bought a 95 honda accord v6 auto from a guy on craigslist and he told me all that was wrong with the car was the water pump was bad and that because of it the engine stalls out because ait is getting in the engine but i wanna know what are the signs of a bad water pump because the car turns on the stutters like revs by itsself but as soon as i press the gas it trys to rev but stalls out almost instantly please help me then the starter just went so what doews that sound like to you also after a while it might drive around with no problem SOMETIMES…..sometimes it starts lets me drive down the street the starts to stutter like its out of gas then stalls out

    • ChiltonDIY says:

      Caution: The water pump is driven by the timing belt, the water pump could lock up and break the belt resulting in engine damage. If you have a bad water pump it will leak around the crankshaft pulley. You should see antifreeze on the ground. Have the system pressure tested. Are you losing coolant? The running problem might be something else.

      • Evan says:

        yeah it leaks a little not too much but idk it doesnt over heat or anything all the car lights work with no problem im thinking it might be the fuel pump also but i know nothing of cars getting a new starter fri. if you dont mind can u give me some signs to look out 4 when i get it started so i can give u more info to better figur out wats wrong

        • ChiltonDIY says:

          Scan the vehicle to check for diagnostic codes that may help in your diagnosis. I believe the V6 should have an OBDII connector. If you think it is fuel-related, I would check the fuel filter and fuel pressure to rule that out. Don’t forget about the water pump and timing belt! Have you opened up the radiator cap (when cool) to actually check the coolant level? How are the basics, spark plugs, distributor cap, rotor wires? Is the timing okay?

  4. Tony says:

    I have a ’94 Plymouth Voyager w a fuel pump that I’ve replaced a few months ago. Now, when I turn the key, it starts or not, 100% of the time, based on the fuel pump hum. So it’s either the fuel pump itself or the signal to the pump. Is there a test for this that doesn’t include dropping my tank?
    Thanks much,
    Terry

    • ChiltonDIY says:

      Hi Tony. You might have to drop the tank down to check the connection, see TSB# 08-28-94. TSBs or Technical Service Bulletins are released by the vehicle manufacturer when there is an issue that occurs with a vehicle. You can access the TSBs and Recalls for your vehicle with a subscription to ChiltonDIY at http://www.ChiltonDIY.com.

      If the van mainly won’t start after the vehicle has sat for hours, it could be a defective regulator. If the fuel pressure regulator is leaking it will not hold pressure in the fuel rail. That will cause a prolonged crank time The fuel pressure in the fuel rail must not drop off. I would check the fuel pressure; leave the gauge connected and turn off the ignition switch. The fuel pressure should stay constant within about 5 lbs. (53-57 psi.).

      You did change the fuel filter; when a fuel pump goes bad you always install a new internal and external filter.

  5. ced says:

    have a 94 Pontiac formula lt1 5.7 and when i drive my car for 20 mins or do it Back fires then dies. Now it wont start but it acts like it wants to. Can u plz help im tired of messin wit this car

    • ChiltonDIY says:

      Hi Ced. Sounds like you need to start with the basics. Scan for any OBD1 trouble codes. Check the fuel pressure, engine compression, and ignition system. Check for spark on all 8 plugs. Use caution and a spark tester. When handling secondary spark plug leads with the engine running or starting, use insulated pliers and exercise care to prevent a possible electrical shock.
      What is the condition of the ignition wires, plugs, cap, and rotor? The distributor is behind the water pump.
      If you rule out all the basics and the problem is still present, you may have a faulty ignition module or crank sensor

  6. Mike says:

    I have a 1997 Ford F250 with a 460, 90,000 miles, new spark plugs, wires, cap, rotor, O2 sensors, idle control valve. No check engine codes. Runs and idles great, good power, no pinging, anything. I can hear the fuel energize before startup for both tanks. Only problem is that sometimes is that if started cold, run a short period, shut off and sit for a while (30 minutes or more), it will not restart on the first time, takes two extended crankings to start. Other than that it starts properly once restarted. I tried it five times in a row after hot restarting, and every time it started perfectly.

    • ChiltonDIY says:

      Hi Mike. Sounds like a hot soak problem. If no codes are present and all the basics are okay, you may have to check the fuel and ignition when the truck acts up again. Did you run a wiggle test? Sometimes it can be like looking for a needle in a haystack!

  7. Kasey says:

    I have an 86 fuel injected bronco. My fuel gage was not working, so I dropped my tank, and replaced my fuel pump. Well, I was going to check the float, and I broke the pump, so I had to replace it. Well, I did so, and I was able to drive the truck about 8 miles when it started to spit, and sputter. The fuel pump is not engaging. I pushed the valve on top of the motor, and I am not getting much pressure in the beginning, then it goes to nothing in about 2 seconds. I don’t have a fuel gauge to check the pressure, but like I said it does to nothing at all in a couple of seconds. I’m almost positive my fuel pump is bad, but I just bought it, plus it’s a pain to drop that tank again. I’ll do what I have to fix it though. But I want to make sure that is what the problem is before dropping the tank again. Could my fuel relay switch be bad? I don’t know anything about motors. The truck was running fine, and would start every time when you first hit the key w/o having to do anything else. But since I dropped the tank, and changed the fuel pump, it hasn’t really ran since.

    Thank you for taking the time to read what I have going on!! I am looking forwaed to hearing from you!!

    • ChiltonDIY says:

      Kasey, if the problem developed from changing the float and pump, you will need to drop the tank (again) and recheck your connections — inside and outside the tank.

  8. Bryan says:

    I have a 1997 Grand Am GT Pontiac. I just replaced the fuel pump and relay. It Still has same issue; cranks but will not start. Can I bypass the PCM in order to get power to the Pump? I believe there to be low voltage at the pump?

    Thanks

  9. Bryan says:

    Wont this tell me if the PCM is Bad? and how do I do it?
    Thanks

    • ChiltonDIY says:

      Hi Bryan.
      First off, check the fuel pressure with a gauge, and verify that you have good spark to all the plugs. Scan for codes. Are you sure it is a fuel problem?
      TSB #71-65-45 “Engine cranks but does not run” may be helpful. The Technical Service Bulletin (TSB) is available when you subscribe for your 1997 Pontiac Grand Am at http://www.ChiltonDIY.com.

  10. Melory says:

    I am having a problem with my 2004 F150, I ran out of gas the other day…I then went to fuel up with gas and now tha gas is not pumping properly it keeps stopping and takes forever to put even $40 buck in. What is going on?? I changed the fuel filter didnt make a difference. Could this be my fuel pump causing this issue??
    Thanks

    • ChiltonDIY says:

      Hi Melory. It sounds like an EVAP problem! There could be blockage or a faulty fuel vapor vent valve. If the vent is blocked it’s like trying to blow into a soda bottle — it won’t work.

  11. Felix S. says:

    Hello everybody.

    So, this morning, I start my car, and everything was fine for a while.

    After stopping on one of the 20 or so traffic lights I go thorugh on my way to the office, I notice that the car does not seem to be accelerating that well. It gets to 40-45 eventually, but not as fast as it normally would.

    I stop to get something to eat, and when I put the car in idle before shutting off the engine, the engine shuts off by itself. I’ve had this happen to me before a few years ago, and it turned out to only be a broken exhaust system hose, which after a $45 fix, eliminated the problem.

    I start the engine again, and this time, after I reach 30 MPH or thereabouts, the car shuts down.

    When I bring the car to a complete stop and try to start the engine again, I hear a “disengaged” crank, and the engine does not start. By disengaged I mean as if the engine was not there at all.

    I keep trying to start the engine, and over the course of the next few minutes, the cranking starts sounding more and more ‘engaged’ during every start attempt, until the engine starts again, and I can drive again – as long as I do not go over 30 MPH or thereabouts.

    I wanted to check and see if anybody here has had something like this happen before, or has any idea what this could be.

    Car is a 2002 Ford Escort ZX-2.

    Thank you.

  12. AJ says:

    I have a 97 Chevy Blazer V6 4WD, I am having a problem of the car stalling like it is out of gas. I put $10 worth of gas in the car (I know that is not much) went 12 miles and it cut off going down the road. I had to get more gas to get it to start back up, is this a sign of the fuel pump going bad or could I be loosing gas somewhere. And it usually takes about 10-12 dollars worth of gas to start back. Also when it does this I usually have to be jumped off because my battery goes dead trying to start it. Thanks in advance for your help and advise. AJ

    • ChiltonDIY says:

      Hi AJ! I would check the fuel pressure and volume of the fuel. Does the Blazer have trouble with a full tank of gas? The strainer could be missing or partially clogged. You may have to drop the fuel tank and inspect the fuel pump assembly. Check for dirt in the fuel tank.

      This is a good time to repeat this warning:
      Caution: Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well-ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.

  13. Ashley says:

    Hey I have a 2000 toyota solara and I been having major problem with the fuel system my car wouldnt start it will comr on and poot off so I got the fuel pump changed and the filters so.my car started the next day I was driving it cut off again so now when I try to start my car it sounds like its about to come on but the car will shake and making a poot sound it wont start up

    • ChiltonDIY says:

      Hi Ashley.
      Have you had the vehicle scanned for diagnostic codes? It sounds like it could be an ignition malfunction. If no codes are present check the ignition system and double check the fuel system. Without codes to point you in the right direction, you need to check all the basics.

  14. wak says:

    My car takes a bit of time to start up but when I’m driving it sometimes just shuts down on me usually when im slowing down I have noticed that it is usually shuts down when it goes below 1 and a half revs

    • ChiltonDIY says:

      Hi wak. If your car stalls when slowing down, it usually indicates a problem with the base idle control. What type of vehicle, year and engine/trans?

  15. Rick says:

    I have a 96 Cherokee and my problem is periodic back firing and lost of power when I floor the pedal. I recently changed spark plugs and iac sensor. It helped with my idling problem, however it continues to stall and back fire. Self check of the computer said it was an idling problem. However when using a scanner the code showed an up stream o2 sensor.

    • ChiltonDIY says:

      Hi Rick.
      I would clear the codes, drive the vehicle and then re-scan for codes. If the O2 sensor code comes back, verify that the O2 sensor is bad.
      If the O2 sensor is bad, install the new sensor, clear the code and run the vehicle to verify the problem is fixed.
      Is the fuel pressure okay? A lean condition could set the O2 sensor code. Check the fuel pressure and check for vacuum leaks.

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