How do I Know if I Have a Bad Fuel Pump?

Malcolm Tatum
Malcolm Tatum

Along with the freedom that comes with owning a vehicle, there is also the responsibility to keep the engine and other components of the car or truck in good working order. Unfortunately, even with the best of care, some engine parts will eventually require replacement. The fuel pump is a prime example. If you wonder whether or not you have a bad fuel pump, here are a few signs that it is time to get a replacement.

A man filling up his gas tank, which can help prevent the fuel pump from going bad.
A man filling up his gas tank, which can help prevent the fuel pump from going bad.

One of the early warning signs of a bad fuel pump is the development of a high pitched sound when the engine is first engaged. Different types of fuel pumps will make slightly different sounds. This phenomenon has been described as a sound somewhat like a tea kettle whistling, while others claim the sound was more like nails scraping across an old fashioned chalkboard. Regardless of the exact sound emitted by the fuel pump, it is important to get your vehicle to a mechanic quickly. The fuel pump is not likely to keep functioning much longer.

The fuel pump is essential to steady operation of the automobile.
The fuel pump is essential to steady operation of the automobile.

Sudden trouble accelerating can also be a sign that you have a bad fuel pump. Because the fuel pump is not supplying an even flow of fuel, the rest of the engine cannot perform at peak level. While there is also the chance that the problem is with the filter, your best bet is to have the fuel pump checked as soon as possible, so the uneven acceleration does not have a chance to progress on to shutting off while on the road.

Low fuel pressure is another indication of a bad fuel pump. Part of what makes an internal combustion engine run smoothly is the constant even pressure created by the pump as it moves fuel into the system. As the pump begins to malfunction, the pressure cannot be maintained. The low pressure may also manifest as an inability to start the car even though the starter and solenoid switch are in perfect working order.

One way to prolong the life of your fuel pump is to make sure you never run out of gasoline. Always keep enough fuel in the tank for the pump to be submerged in gas. Along with keeping at least a quarter tank of gas on hand at all times, it is also a good idea to make sure the filter is replaced on a regular basis.

Failure to replace a bad fuel pump in a timely manner may cause other car parts to work harder. This will only lead to even more costly repairs that must be made, as well as increase the chances of a breakdown at the worst possible moment.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including wiseGEEK, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments


I have a Mercedes C250 diesel 1998. Every morning, mostly when the weather is cold, it struggles to start, but once started it's OK unless it's very cold weather and it's parked over five or six hours. In summer it's fine but sometimes struggles depending on the temperature. The glow plugs have been changed recently.


I have a 2000 Honda Civic coupe and I have been experiencing where my car is jumping like and doesn't want to drive like it wants to stall and then I smell something. It seems dangerous so I drove it home and left it there, but I do want it fix asap so I can run all the errands I have to. What do you think this is and how I can fix it?


I have a 92 Honda Accord. Yesterday, I was driving when my car suddenly slowed down and the engine decided to turn off. Luckily, I was able to pull off the street before it died completely. I’ve also had the problem of whenever I want to go somewhere during the day, my car will crank but not turn over. If I let it sit for hours and come back, it will work just fine, but starting yesterday it would just die on me when I'm driving.

The battery is fine (I don’t know about the alternator). The car works just fine when it's cool out, like in the morning or night. I don’t want to pay for an alternator or a fuel pump assembly if I don’t need to. I just don’t know if this is common.


I have a 1994 Chevrolet k1500 350. I changed the starter and now there is no fuel to the injectors.


I have a 2001 Pontiac Grand Am GT. My car had been losing power and shutting down sometimes, and the battery would seem weaker but it would start after the car sits for 15 minutes, but would do the same thing once I started driving again! Now it will not start. It cranks but won't fire! I hope it's only the fuel pump and not the timing belt.


I have a 1995 Mercedes Benz S 420. The car will start like a dream, very smooth, but in about 30 minutes, when the engine gets hot, the car will stall, won't start, but if leave it for an hour or more, then the car will start again like a brand new car? I am going out of my mind. Any help?


I was driving my 1987 chevy suburban an was running great then all of a sudden it was very sluggish an would hardly go. The only way to keep it running is pump the gas pedal up an down. What could it be? It has a 350 V8.


My car left me stranded the other day. it just shut down while I was idling and now it won't start. there is no spark and no fuel pump hum when I turn the ignition to on. The relay is good and also the spark plugs and distributor and wires were replaced a while back. It's a 1994 honda accord.


i have a 1987 V6 Dodge Dakota and when i drive a few miles the fuel pump loses its prime. it also does the same thing under heavy loads.


@galen84basc -- I would check your spark plugs first. You can do this by grounding a spark plug checker to your engine block, then connecting it to a plug wire while you (or a buddy) is cranking the engine.

If your ignition is good, you'll see sparks coming off the tester. If your plugs are good, double-check your timing belt, but if that looks fine too, then you're probably looking at a fuel pump issue, most likely a clogged filter or weak pump, or worst case scenario, a dead pump.

If your plugs and belts are good, I'd have a mechanic check out your pump so you can figure out if you need a new one or what.


I've been having some car trouble lately and think it might be the fuel pump.

When I try to start the car, the engine will crank and turn over, but it won't start all the way. Somebody told me that it might be my fuel pump, but it seems to me that the a problem with the ignition would be more likely.

Anybody with car smarts know if this could be caused by a bad fuel pump, or is it more likely to be a problem with the ignition or timing belt?


Another way to keep your fuel pump working longer is to keep high quality gasoline in it. That keeps the pump from getting clogged with debris, which is one of the most common causes of fuel pump failure.

You should also make sure that the gas doesn't have any water in it -- this can really shorten the life of your fuel pump. Of course, you don't have to put in the really expensive super high quality gas all the time -- just a decent, clean gas that suits your car will do the trick.

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