Volkswagen Fuel Pump

FAQs— Volkswagen Fuel Pump

1. I still have the stock fuel pump in my Volkswagen. Now, my ride is starting to act up. How do I know if it's the fuel pump or another component? What are some things to watch out for?

If the problems you are experiencing with your car are engine sputter at high speed, loss of power while accelerating, or sudden power loss when your ride is under stress, your fuel pump might be the culprit. It could be that some of its elements are already weakening, making the pump unable to keep up with the vehicle’s demands. Or, the pump can no longer deliver the necessary pressure to consistently supply fuel.

2. I know that most symptoms of a bad fuel pump involve stalling or starting difficulty, but can a bad pump cause surging? What's the reason behind this?

Though it’s the opposite of the common symptoms of a bad pump, a defective pump can cause surging. This is because as the pump ages, it can develop irregular resistance within its motor, therefore causing a situation that makes the pump unable to draw enough electricity to maintain the necessary pressure for steady speed. With sudden rise in pressure, the vehicle may surge. At consistent speeds, the vehicle may move along normally even though it’s surging. But without driver intervention, the vehicle will surge forward, like what it does when the brake pedal is being stepped on.

3. I own a diesel Volkswagen. Are specific fuel pump issues associated with VW diesel cars?

Much like other vehicles, there have been reported stalling incidents with VW diesel cars because of a failing fuel pump. Volkswagen, however, stressed out that if the fuel system damage is due to the owner’s failure to comply with ASTM-D -975 Grade 2 S15 standards, this will not be covered by the warranty.

4. I am having problems with my Volks, and I would like to know if the culprit is the fuel pump. How do I test my Volkswagen fuel pump?

You can test your Volks’ fuel pump in two ways—through an electrical test or a fuel pressure test. The electrical test is done by checking the fuel pump fuse for any sign of failure, checking the pump’s voltage, and performing a drop test using a voltmeter to make sure that the power wires and the ground wire are both working properly. Fuel pressure test, on the other hands, involves inspecting the filter for clogs and testing the pressure using a fuel pressure gauge. You just need to connect the gauge to the fuel pump fitting and ask someone to rev the engine while you check the gauge. The pressure reading should be the specs listed on your manual. If there are significant differences in your reading, it might be time to replace your fuel pump.

5. I’m having problems with low fuel pressure in my car. I’ve tested the pump, but it seems to be in good shape. What are the other factors that can cause low fuel pressure?

Low fuel pressure is usually caused by the pump’s inability to increase the pressure to the manufacturer’s recommended specs. The primary reasons for this are fuel leak, clogged fuel filter, kinked fuel inlet, or a really bad pump. Leaks can be easily identified and remedied without a need to replace the pump. A plugged up filter can simply be replaced to improve the fuel pressure. However, if it’s the pump itself that’s losing its capacity to bring the fuel pressure to the required level, then you have no choice but to replace it.

6. I had replaced the fuel pump in my VW after just 80,000 miles on the road, and I don't want the same thing to happen to my new pump. Any maintenance tips?

You can extend the service life of your Volkswagen fuel pump by using only the manufacturer’s recommended grade of fuel. You should also keep your pump from overheating by making sure that the tank won’t run out of gas. Besides overheating, an empty tank, when filled with fuel, can cause thermal shock to the pump. It’s also a good idea to replace the fuel filter at the recommended interval. When fuel pump warning signs start to come up, do not, in any way, ignore them.

7. I have a diesel Volkswagen vehicle, and I read about the problem with fuel gelling during winter. Any tips on how I can prevent this?

One way you can prevent this is to add an anti-ethanol agent. If you don’t have such, you can also try adding kerosene as it can help lower the fuel’s plug point temperature and decreases its viscosity, thereby reducing the chances of diesel gelling in low temperatures. There are also additives and fuel treatments that you can add to the diesel fuel to help reduce the formation of paraffin crystals that cause gelling.

1. How can I tell if my Volkswagen has a bad fuel pump? What are the signs? The vehicle seems to lack power lately.

A failing fuel pump will cause deficiencies in fuel delivery. As a result, the engine may perform poorly. When under load, you may notice lack of power. The engine may be difficult to start or won't start. If you've already checked the battery and the charging system of the vehicle, and they all seem fine, the problem may be with the fuel system, probably a faulty fuel pump. Because of the failure of the pump to create the needed pressure for fuel flow, the engine may run lean, which may trigger a fault code and cause the check engine light to flash. The engine may also suddenly die while driving or you may hear a whining noise from the rear of the vehicle.

2. Does low fuel level in the tank really cause fuel pump failure and damage? Is it true or just a myth?

If the vehicle often runs low on fuel, this may eventually cause damage to the pump since the fuel cools and lubricates the internal components. Heat won't be dissipated easily without this fluid. If the fuel level is near empty or low, the motor has to work double time to create sufficient pressure for fuel flow. Reduced fuel weight can affect the fuel pump function. Over time, the pump can wear out due to reduced cooling, insufficient lubrication, and the stress from having to work harder.

3. Is it true that the vehicle tank must be drained if the vehicle will be stored or won't be driven for a while? They say that this can potentially ruin the fuel pump due to corrosion. How can moisture find its way through the fuel pump when the vehicle is in storage?

If the vehicle isn't driven or is stored for quite some time, unused fuel in the tank can attract moisture. Eventually, this causes the fuel to separate. There can be water in the fuel, leading to corrosion. Moisture in the fuel will ruin the metal components in the tank, causing it to fail eventually. So when the vehicle won't be used for an extended period, it would be best to drain the gas tank. Just refill it with fuel when this will be taken out of storage and will be in service.

4. How can fuel pump failure be prevented?

It'll help if you won't let the gas tank run low or almost empty on fuel since this cools and lubricates some parts of the fuel pump. With less fuel, the pump has to create more pressure to sustain fuel flow, overworking the motor as a result. Also, make sure that there's no water in the fuel and that it's not attracting moisture, which can corrode the pump's metal components. More importantly, don't let fuel get too dirty. Replace the fuel filter as needed so that it can trap dirt and small particles. This will keep debris and contaminants from getting into the pump and ruining the commutator and brushes on the rotors. Check the connections on the fuel pump before replacing the motor to make sure that the pump replacement won't wear out prematurely.

5. How can you test the Volkswagen fuel pump to see if it's failing and causing the engine problems or if it's still in good condition?

Several tests can be done. You can do an electrical test by checking the fuses and voltage at the pump using a voltmeter. Also, check for a bad relay or corroded wires, which can be the underlying cause of the fuel system problem, and not a faulty pump. A fuel pressure test using a pressure gauge can also be done.