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!

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

  1. joe says:

    hey, ive got a 76 chevy c10 with a 350 bored. 30 with a mild cam and a holly 650 carb. she was sitting for a while got her running ran fine for a day or two, took her to get an oil change and she was bogging real bad leaving a stop this started after the 2 days of running perfect. then driving hone she kept stalling then would be had to start. towed her home and after sitting for about a week she ran fine drove for an hour with no problem now shes stalking again with the hard start. if i sit n let her cool down i can get about a mile before she stalls again, any ideas? also dunno if it makea a difference but there are no cats just stright pipes.

    • ChiltonDIY says:

      Hi Joe.

      You’ll want to determine whether it is a problem with spark or fuel.
      Check the carb. Is it dripping or running rich? Maybe the needle valve is sticking or the power valve could be bad.
      If you have points, check the points and condenser and make sure they are not burnt and closed up. Check the dwell and timing.

  2. Brianna Jimenez says:

    Hi, I have a 2002 Chevy Malibu, and it sometimes has trouble starting. I spray starting fluid and it turns on but recently its been wanting to turn on but the car starts to shake then cuts off. After that we have to wait for like a hour or so for it to start again. We’ve replaced the spark plugs and can hear the fuel pump coming on. I’ve used seafoam to try and clean out any clogs, and still has same issues. What else could it be?

    • ChiltonDIY says:

      Hi Brianna.

      Check the fuel pressure
      Scan for codes
      Check to see if you have a good hot spark on all cylinders
      Check the compression

  3. mia says:

    Hey, I have a 2002 silverado truck v6, as I was driving hme I heard a noise nd it sounded like a struggle. ( I had gas but I aspiring drive a lot on close to empty) I made it hme but it sounded funny and it seem to make a sputtered noise as I press the gas and if I increase on the gas it seems like its going to die. It did a few times but started up again. When I reverse it fire out too. Is it my fuel pump or vaccume leakage fr what I was told. Jus wanna a accurate answer thanks

    • ChiltonDIY says:

      Hi Mia. Running on empty can damage your fuel pump and filter and cause your engine to run poorly – here’s why:

      Gas is not completely clean. If you run your truck on E a lot you are sucking up debris/ silt on the sock which filters the gas in your truck’s fuel pump. The silt clogs up the sock and the fuel can’t get through.
      When you run the gas all the way down to E and you get a little moisture in the tank, say for example by pumping gas in the rain, then you may be trying to run the engine on water. The engine won’t run on water.
      In addition, the fuel pump is submerged in gas which helps keep it cool. When there’s not much gas the fuel pump doesn’t keep cool and experiences more wear.

      Without seeing the vehicle, it sounds like you may need a filter and may have a failing fuel pump.

      Check the fuel pressure.

      • mia says:

        Thank you for your help. The problem was not my fuel pump, I was told if it was it wouldn’t start. my friend did a code scan and it was reading a misfire which was the noise I heard a couple times, so it ended up needing tune up. And it runs good and it dosent make that funny noise when I start it up. Apparently my wires nd rotor was irked or something.

  4. patrick says:

    i have a 2000 Chevy venture it will start and run rough then if you turn it off it wont start again if its let sit for a couple hours it will start again and it will get me to where I’m going but then i haft to let it sit again now when i start it it idles but if you step on the gas it sputters and when your going down the road it doesn’t want to get up to speed i have replaced the ERG and replaced the fuel pressure regulator could it be the fuel pump please help me I’m at my wits end

  5. patrick says:

    sorry also when it stops running or when it goes out the exhaust pops and there’s what smells like gas or exhaust

    • ChiltonDIY says:

      Hi Patrick.

      - Scan your Chevy Venture to see if you have any misfire codes.
      - Have you checked the fuel pressure? Check your ChiltonDIY subscription for the correct fuel pressure specification (under Engine Mechanical Specifications).
      - Was the fuel filter replaced?
      - A clogged exhaust system (catalytic converter) can also cause your problem.

  6. 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?

  7. 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?

  8. 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?

  9. 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.

  10. 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

  11. 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!

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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?

  20. 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.

  21. Joshua L says:

    Maybe you can help me! I have 1994 ford explorer xlt. Recently it started smelling like gas.. I thought I had a gas leak from maybe the tank but when I looked at the tank there was no gas coming out. But! There was gas that looked like it was falling on top of my tank and trickling down the side of the tank! So I thought I had a bad fuel line that was leaking! My car has trouble starting in the morning after sitting for about 8 hours. But it will start. Soo took it to a shop told the guy what was happening and he told me that it was the fuel sending unit. He told me it would cost me 1100 to fix! That’s crazy! He didn’t even look at the car! I’m not sure what to think. Is a fuel sending unit and a gas pump the same thing? How much do you think it would cost to fix? Do you think maybe by any chance it’s a fuel line above the tank?

    • ChiltonDIY says:

      Hi Joshua.
      I would drop the tank to see what is leaking; it could be a fuel line or the seal for the fuel pump/sending unit assembly.
      Most newer fuel pumps are usually sold as an assembly with the fuel pump and sending unit together.
      Have you actually checked the fuel pressure?
      It could be a hole in the top of the tank. If you are smelling fuel I would have the fuel system physically inspected.

  22. Jeremy says:

    Hi! I have a 72′ ford f100 with a 302, and a 2bbl carb and an inline electric pump. The fuel pump makes noise but unless the fuel tank is topped off it will stop pumping fuel to the filter/carb. I’m at a loss, is the fuel pump bad? Can it click and just not be pumping? Or is somyhing worse happening?

    • ChiltonDIY says:

      My first question is why was an electric fuel pump installed? I would check the fuel system. Is the fuel pick up screen inside the tank clogged?
      I had a 68 Mercury Cougar and the fuel tank screen was clogged with silt. I gave me a fit until I dropped the tank, cleaned out the silt and installed a new strainer screen.

      • Jeremy says:

        Not entirely sure why they added the electric fuel pump. I got the truck third hand. Too lazy to repair the mechanical pump? Not sure if the screen in clogged. That may be the next step. I am just wondering if a fuel pump can run but not hold a suction on the tank (internal seal blown and sucking air?). It won’t pull from either the external tank under the bed or the main tank behind the seat. Would I see silt in the inline fuel filter? it seemed clean. and thanks for the fast response!

        • ChiltonDIY says:

          Jeremy, I would check all the fuel lines to see if they are clear back to the tank. If the fuel lines are clear and you can blow air into the tank, than you could have a faulty pump. And yes the fuel pump can lose its prime and cause prolonged starting.

  23. Joe says:

    I have a 1995 g20 , the car starts fine but this morning I drove it I work and it was fine but during my break it died as soon as I started it , I tried again and it died after I started it ten the third time I have it had and it was fine , and also when I’m going uphill the car feels underpowered . What could be the cause of this ?

    • ChiltonDIY says:

      Hello Joe. I would scan for any related trouble codes, and check the base engine idle and timing.
      How are the filters and spark plugs?
      Check all the basics first. Import fuel pumps usually don’t have as many malfunctions as domestics.

      • Joe says:

        Sorry for the typo , I was driving at the time lol , but ill go to a shop to Check it out I don’t know anything about cars . Thanks anyways

        • ChiltonDIY says:

          You are welcome Joe. You were probably kidding about texting while driving.
          Did you know in 2011 about 1 in 4 accidents involved cellphones according to textinganddrivingsafety.com?
          11 teens die EVERY DAY from texting while driving according to the Insurance Institute for Highway Safety Fatality Facts.

  24. Zachary says:

    Hi, I have a 1989 Toyota Camry LE 6 cylinder that started cutting out until it died, I waited about 5 minutes and tried starting it and it fired right up but now when I put it in gear it feels like it isn’t getting enough gas to go. Also it is now making a weird noise whenever it is in gear any ideas?

    • ChiltonDIY says:

      Hi Zachary.
      When there is a problem starting or driving a vehicle, two of the most important checks involve the ignition and the fuel systems: Is there spark? And is there fuel? This will often lead to solving most basic problems.
      Scan the vehicle for related trouble codes.
      Is the noise coming from the motor or the transmission? Does the Camry have an automatic or a manual transmission?
      Has the fuel filter been changed in the last 20-30 thousand miles?

  25. erik says:

    Hi i have a 95 saturn sl1. Died on the freeway. Battery still fresh, when it died it was a sputtering death ” real sudden and quick” I get spark ” i put a inductive timing light on the leads” and the voltage is 14v. Im assuming a fuel issue. I will change the fuel filter reguardless, but how can i rule out the pump? It will not start after 5 minutes of run time. BUT it will start if i dont try to start it for like an hour and it will run for around 4 minutes before dying. help….

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