A faulty fuel pump can cause you a lot of trouble. Depending on the vehicle model, replacing a faulty fuel pump can cost up to $1000. This is because some models have their fuel pump attached to the fuel tank and then the entire rear suspension system under it. So, if your fuel pump is faulty, is it safe to drive with a faulty fuel pump?
”It is not safe to drive with a faulty fuel pump because when a fuel pump is faulty, it can no longer supply the fuel system with constant fuel pressure and your vehicle won’t start, it can stall, or even completely shut down at any time. Apart, from possibly doing damage to some engine components due to low fuel supply, your vehicle can shut down while you are driving on the highway which can be a safety issue.”
Top 10 Signs Of A Faulty Fuel Pump
A faulty fuel pump will give away some signs that even an untrained mechanic can notice and diagnose. All you have to do is listen to your vehicle. Here are the top 10 signs of a faulty fuel pump:
1. Vehicle won’t start
If your vehicle cranks but won’t start, there is a chance that the fuel pump is faulty. Because the vehicle cranks, you can rule out a faulty alternator and battery because there is a power supply to the vehicle.
You can spray starting fluid into the intake and try to start your vehicle. If you are able to start your vehicle with a starting fluid sprayed directly into the intake, that means that the fuel system is faulty.
2. No buzzing noise during start-up
Have someone open the fuel tank cap and listen for buzzing noise when you start your vehicle. If there is no buzzing noise coming from the fuel pump, that means that the fuel pump is no longer operational.
3. Jump start the fuel pump by tapping
Since the fuel pump is operated by power, it could have some loose wire. You cannot get to the fuel pump without removing some parts. But, since the fuel pump is attached to the fuel tank, you can use a rubber mallet or a two-by-four and tap on the fuel tank.
Try tapping softly so you don’t damage anything. You just want to try tapping so you can start the fuel pump one more time. If the vehicle starts, it means that the fuel pump is faulty and you should take your vehicle to the repair shop to replace the fuel pump.
4. No power supply to the fuel pump
This can be done on a vehicle with an easy access panel to the fuel pump. Usually, the pumps are attached to the fuel tank and it would be hard to check the power supply without removing any parts.
Check for power going to the fuel pump using a voltmeter. If power is going to the fuel pump but your fuel pump isn’t starting or buzzing, the fuel pump is faulty.
5. Faulty fuel pump relays
You need to check all related fuel pump relays and see if they are faulty. The fuse box is usually located in the engine bay, on the driver side. However, there are many fuses and this can actually be very confusing if you don’t know what you are looking for.
Each fuse is assigned to a different part. You should check your manufacturers manual to see which fuses are assigned to your fuel pump. Take out the fuel pump fuses and inspect them for any damage. If you are uncertain about some fuses, just replace them with new ones.
6. Fuel pump makes whining noise
A properly operational fuel pump makes a buzzing noise when it’s working. This noise is quiet but you can hear it if you are near the fuel tank. Once the noise changes from a normal buzzing sound into a whining noise, this is an indication that there is something wrong with the fuel pump.
A fuel pump will not just go bad in an instant. A fuel pump that is about to fail starts making whining noises. This noise is different from the buzzing noise. This is actually the first sign that a failing fuel pump gives.
7. Vehicle stalls when accelerating
When a fuel pump starts to fail, it is no longer working at a full capacity. You are used to accelerating as soon as you hit the gas pedal. But, when the fuel pump starts to fail, you will notice the difference when you press the gas pedal.
Because the fuel pump is about to fail, it is no longer supplying enough fuel pressure to the fuel rail. The vehicle will stall even with you pressing the gas pedal. This is an clear indication that the fuel pump is failing.
8. Vehicle stalling overall
If your vehicle stalls when you are accelerating is different from your vehicle stalling even when you are driving your car normally. To accelerate, the fuel pump needs to supply the engine with more fuel. That requires the fuel pump to work twice as hard.
But, if you are driving your vehicle at a normal speed, but it is still stalling, this means that the fuel pump is not capable of performing its job even with no additional pressure added. You should replace your fuel pump as soon as possible.
9. Engine misfire
When a fuel pump is faulty, it provides low fuel pressure. The low fuel pressure can cause the fuel injector to spray less fuel which can cause a misfire. Before you check your fuel injectors, make sure that you check your fuel pump first.
10. Vehicle sputter and surge at high speeds
Another common sign of a faulty fuel pump is if your vehicle sputters and surges at high speeds. A faulty fuel pump struggles to deliver constant fuel pressure. The fuel supply is not constant either and there is not enough fuel for the combustion to occur constantly.
If you are driving at high speeds, that means that the system needs more fuel at a constant level. A weak fuel pump cannot supply the combustion chambers with a constant flow of fuel and your vehicle will start to sputter and surge. It is not safe to drive with a faulty fuel pump because maybe you want to pass a vehicle and you are counting on your car to accelerate, but instead, it will sputter and you could end up in an accident.
Can a Faulty Fuel Pump Cause High Fuel Consumption
A faulty fuel pump could cause a high fuel consumption, but this is not always the case. Usually, when the fuel pump is faulty, there is not enough fuel supply to the engine. Meaning, a faulty pump cannot provide a constant fuel pressure and your vehicle will start to stall while accelerating, sputter at high speeds or it won’t start at all.