Symptoms of a Bad Fuel Pump

symptoms of a bad fuel pumpHow do I know if I have a fuel pump problem with my car. I can crank the engine over but the car won’t start.  I think I can hear the fuel pump making noise inside the tank.  Not sure. What are the symptoms of a bad fuel pump?



Hi there Bill,

Well if you can hear the fuel pump coming on (makes a whining noise inside the fuel tank for 2-3 seconds when you turn the key to the ON position) then it could be fine or it could be coming on but not have enough strength to supply the engine with the proper fuel PRESSURE, which is most important.

Usually a fuel pump fails once it has been sitting a little while and you go back out and try to start the engine again. It is a temperature issue, pump getting hot, then cold etc. that cause it to not work properly.

What you can try is this. Take a small block of wood or your fist if you feel comfortable with that and rap on the sides and bottom of the fuel tank AS someone is cranking the engine over.

If the car starts, you have a bad fuel pump and it needs to be replaced. If it does not start, you could still have a bad pump, or you have another issue like lack of spark to the spark plugs.

If you have a pickup truck, it is sometimes easier to remove the 4 bolts holding the bed down and move the bed back just enough to gain access to the top of the fuel tank. You will need a few friends, but its faster, easier and safer than dropping the fuel tank to get to the pump.

And Murphy’s law is true, you will almost always have a full tank of fuel to deal with, which is heavy and dangerous to work around.


Reader Follow Up

Thanks a million for your suggestion on hitting the gas tank to get my 96 stratus to run.  I had not started the car for a month or so, so while it turned over fine, it wouldn’t catch.

A couple of hits w/ a broom on the gas tank and it started like usual.  BTW, it’s got a fuel pump w/ maybe 20k on it.  Think I”ll put some gas cleaner in the tank in case the fuel pump is somehow stuck due to non use


Posted in: Won't Start Issues

8 Comments on "Symptoms of a Bad Fuel Pump"

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  1. jim davis says:

    2003 explorer, new fuel pump, fails to start, actron OBD II code reader, says, code ( p0232 ) ( fuel pump secondary circuit High ) what does this mean ? and how do I fix ?

    • Austin Davis says:

      First thing that comes to mind is the loss of a ground, so check your ground circuits. You might have a fuel pump module…not 100% sure on this year model without doing some research….or just call your Ford dealer parts department and ask. The module controls the pump, and could have failed. If no module then you basically have the computer and a relay controlling the pump.

  2. kathie says:

    I was driving my 2000 Ford Mustang Convertible when it started to make a noise and kinda shake. I managed to get home but just barely – when I had to stop for a light I had one foot on the brake and the other on the gas – the light turned green and I had my foot on the gas pedal all the way to the floor and couldn’t get the speedometer needle above 10 (and of course my drive home was uphill – dang!) Fuel pump?

    • Austin Davis says:

      Possible. I would rent/borrow a fuel pressure gauge from your local auto parts store and check the pressure at the engine. Could also be an ignition problem, like a bad spark plug or plug wire or ignition coil or something seriously wrong internally wrong inside the engine. I would not expect to have heard a noise if the “failed” it would have just failed and stopped working, although it can still “pump” just not pump hard enough to keep the engine running properly. My gut says its not the pump but something else.

  3. Rebecca Madden says:

    hi i am rebecca i have a 2000 mercury grand marquis and one day last week i was driving down the street and my car just cut off. I tried to crank it several times but nothing. I had someone stop to help me who sprayed starting fluid in the ejectors( i assume)and it cranked up for a minute then off again he said i needed a fuel pump. I got it towed home my dad looked at it .pressed on a part (i assume injectors) and it squirted out my dad said fuel is reaching threw the top of the engine.turn the switch on and could hear the fuel pump cut on and also my husband went ahead then and replaced the fuel filter. I just want to know what could it be is it the fuel pump after all the sign say that it isnt.

    • Austin Davis says:

      Sorry for my delay. You need to use a manual fuel pressure gauge (you can rent from the auto parts store) and check the fuel PRESSURE at the back of the engine. Just because you can see fuel at the engine does not mean the fuel pump is pumping enough to keep the engine running. IF pump is ok, then I would check the crankshaft position sensor next. You can sometimes bang on the bottom of the fuel tank with your fist AS someone cranks the engine over to jump start a weak fuel pump.

  4. Robin Pearson says:

    I have a 2004 jeep wrangler and I deliver mail with it. Yesterday it would not go more than 20 mph. I would push on the gas pedal and it would rev up. Let rest and cool off seem to do better got up to 40 mph.

    • Austin Davis says:

      If you mashed on the gas and the engine RPM would rev up but the vehicle speed did not increase then I would assume you have a slipping transmission or clutch. If this is an automatic transmission then check the transmission fluid level. If fluid is low, you have a leak, if fluid is full you have an internal transmission wear problem. If this is a stick shift, then you probably need a new clutch.

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