How To Start A Car With A Bad Fuel Pump

Car engines are intriguing machines assembled with several systems built to deliver optimal performance. Engines require a constant fuel supply, and the fuel pump is the system used to provide it.

Mechanical fuel pumps move fuel from the fuel tank to the engine under low pressure through the carburetor. The fuel mixes with air inside the carburetor, the liquid is then pumped into the engine. Mechanical fuel pumps are outside of the fuel tank. The camshaft operates a switch on the fuel pump that uses a diaphragm situated inside the carburetor. The control switch can pull the diaphragm down, allowing the fuel to rush into the carburetor, or pull the diaphragm up, causing pressure to push the fuel out. 

 Electric fuel pumps send a positive electrical current through the fuel lines causing enough force to send fuel to the engine. The electrical current needed is regulated from an electrical ignition switch. The fuel in this system does not mix with air until it hits the cylinder.

The fuel moving from the tank to the engine completes several functions that manage the car’s power. One of the steps is the pump causing the correct air to fuel mixture that produces the energy to start your vehicle. There is always a concern about engine damage if a car part fails, but the car will not start if the fuel pump quits.

Weak Fuel Pump Symptoms

You may be wondering how soon your fuel pump will fail you. Today’s fuel pumps are built to last; however, there are no guarantees the pump will continue with no issues for the vehicle’s life. Luckily there are symptoms the car will experience if the fuel pump is weakening:

  • Low Gas Mileage: When driving a vehicle, we usually become familiar with the car’s average gas mileage. When you notice your vehicle’s gas mileage beginning to decrease, the fuel pump may have a faulty valve that allows more fuel than necessary to leave the fuel tank. Excess fuel will not be used or stored, leading to lower fuel efficiency. 
  • Stalling During Warm Temperatures: There are many reasons a car may stall, but if the stall increases when it is hot outside, this is a symptom of a fuel pump motor beginning to fail.
  • Loss of Power: The fuel pump is regulating how much energy to send to the engine, so if your vehicle demands a surge of power such as climbing a hill, extra weight, or accelerating quickly and there is not enough power to complete the necessary task adequately this is a sign the fuel pump is too weak.
  • Sputtering Engine: When the car is driving at a constant speed, and the engine sputters, this is a sign that the fuel pump is not continuously supplying the needed fuel to the engine.
  • The Fuel Tank Begins to Whine: Low fuel or damaged fuel in the gas tank can damage the fuel pump, causing it to make a louder whining or howling noise that will be very apparent.
  • Surging: When the fuel pump is experiencing a resistance issue inside the motor, it will cause the vehicle to surge forward while driving as if you have stepped on the gas pedal harder.
  • Hard Starting: With every engine start, the fuel pump activates. Over time the pump can weaken, causing several tries to turn over the engine. A weak car battery shares this very familiar symptom making it wise to check the battery also.
  • No Start: The car engine will continue to turn over but will not start. There are several other reasons this happens, but it may be a clear sign that the fuel pump has failed.

3 Ways to Start a Car with a Bad Fuel Pump

There are a few methods to start a car with a failing fuel pump. These are simple suggestions to try even if you don't possess much mechanical ability. Professional mechanics will remind you that this is a temporary solution to a severe problem that is best not to ignore.

  • Fuel Pressure Gauge - Attaching a fuel pressure gauge directly onto the engine will allow the car to start and drive. A fuel pressure gauge usually is in the $40 price range and is a handy tool to have available.
  • Manual Pressure - Using pressure to assist the fuel through the lines is another simple technique to start the car.
  • Engine Heat - The engine overheating due to a faulty fuel pump is possible, but if the car is shut off and cooled, the low temperature can also cause the pump to stall. Maintaining a consistent heat to the engine can allow you to drive the car far enough to reach a repair shop.

A fuel pump is located in one of the most challenging locations to access in a vehicle. Due to the location issue and increasingly superb technology, most fuel pumps are strong enough to last over 100,000 miles or more. Learning the signs and symptoms of a failing fuel pump can save thousands of repair fees. Correct and timely maintenance is the key to the longevity of a vehicle's fuel system. 

According to Kelley Blue Book, it is recommended to first check with the vehicle’s owner manual to know the fuel system's suggested maintenance and how often it will need to be completed. A general rule of thumb is to change the fuel filter every 15,000 miles and go through the entire fuel system every 60,000 miles. You are now equipped with the warning signs to look for and some tips to try if you find yourself stranded on the highway with a bad fuel filter. Maintaining your vehicle correctly not only reduces stress; it allows you to experience all the performance and enjoyment your car can provide.