Fuel Pump: How to check by yourself

For the engine to produce the required torque, it needs fuel. It is fed by a special pump. But sometimes it happens that it breaks down. How to check the operation of the fuel pump with your own hands? Let's consider.

Characteristic

The fuel pump serves to supply liquid from the tank to the injectors. He works under high pressure. Further, the liquid mixes with air and a fuel-air mixture is formed. If the element is faulty, the fuel supply will stop. To maintain the pressure, the pump is based on a special reducer.

About varieties

Depending on the type of fuel system, there are several varieties of these elements. So, carburetor cars use a mechanical pump. On the injector it is submersible and is powered by an electrician. Inside the element there is a special motor and pump. If one of these elements fails, the entire fuel pump stops working.

How to check without dismantling? Symptoms

There are several symptoms that can be used to determine the malfunction of this node:

• Jerk while moving.
• Difficult start of the car.
• Deteriorating dynamics of acceleration. The machine slows down slightly, even if the latch is fully depressed.

Also note that similar symptoms can occur in the event of malfunction of the mass flow sensor or throttle position. It will not be superfluous to check and replace the filter, both gasoline and air. The resource of the latter is 10 thousand kilometers. Determine its wear can be visually. If it is in this state, it must be urgently replaced. As for fuel filters, they are produced in an opaque package. Therefore, it is required to record the replacement regulations. On gasoline cars, it changes every 50 thousand kilometers. On diesel - every 10 thousand (fine cleaning).

Fuse and relay

Both elements can affect the fuel pump. How to test it? It is enough to remove the fuse cover. See if there are burnt elements. On the cover there is a diagram where it is indicated which fuse is responsible for this or that electrical appliance. As for the relay, it can be under the glove compartment, or in the engine compartment. How do I check the fuel pump relay? Everything is very simple. To do this, you need an assistant who will turn on your ignition for your team. At this time you touch the relay with your hand. It should click. If not, most likely, it has become unusable. It also happens that the part does not work because of poor contact. Clean the terminals and check it again. If this does not work, replace the relay.

The relay works, but the pump does not pump

If the element is OK, it is necessary to diagnose the voltage on the fuel pump. To do this, use a multimeter. Check if the voltage is applied to the fuse. Often an open circuit is located in this place. Also check the voltage on the wires of the gasoline pump. If the "ground" is leaving, the multimeter shows values below 12 V.
Probably, wires or terminals are oxidized. You can clean them with sandpaper or thinner.

We call the relay

If the car starts to stall on the move, the reason is the electrical part, namely the relay. We connect a control bulb to it, and the second end - on the fuel pump. Turn the ignition on. If it caught fire for a few seconds and went out, a short circuit occurred in the circuit or one of the wires left.

How do I check the pressure of the fuel pump? Ways

It happens that the element works, but does not give the right pressure. In injector systems, injectors are very demanding on this indicator. Due to low pressure, there may be difficulties with starting the engine, dips in the dynamics. How do I check the fuel pump? This can be done in several ways. The first is a check on the SRT. The price of this service is about 300 rubles. However, you can check the pressure yourself. Now on sale there are special manometers for the pump. But their cost comes to two thousand rubles. You can use the ordinary, which goes for car wheels. Each man is equipped with such a manometer.

Self-diagnosis

The pressure level that the pump reproduces is 6 atmospheres. Therefore it is important to achieve tightness of joints. To seal, you will need a ribbon and a 9 mm diameter pipe. So, how do you check the fuel pump pressure yourself? We open the hood and look for a ramp with injectors. Usually it is covered with a plastic cover. We remove it and see the cap in the form of a wheel nipple. We unscrew a part of the ramp. Be careful - gasoline may leak under high pressure. How to set the pressure? To do this, remove the fuse on the fuel pump and start the engine. After a few seconds of work, it stalls. In the system, there will be no more fuel from the pump to the injectors. You can safely unscrew the ramp, which goes to the fuel pump. How to check further? We put on the hose with our manometer, seal it with a felt tape and secure it with a metal clip for the reliability. Next, the assistant turns on the ignition. At this moment you are looking at the readings of the manometer. If the values obtained are below five atmospheres, then the element is not capable of producing the required pressure.

What next?

Low pressure can occur due to a damaged pump diaphragm or loose connection to the stem. To restore the integrity of the element, it is necessary to disassemble the upper part of the body and tighten the diaphragm, or replace it with a part from the repair kit. If there is a leak between the components of the mechanism, tighten the connecting screws and replace the gasket. The latter also goes to the repair kit.

Replace with a new one or not

If the malfunction concerns the mechanical part, the motorist has two ways of solving the problem. The first is the purchase of a repair kit. It includes all the necessary parts that can break down in the pump. The second is to replace the element entirely with a new one. This is a more reliable and reliable method. But it is worth considering that submersible pumps are very expensive. Among the manufacturers on the market there are both originals and analogs. Experts advise buying pumps from Bosch and Masuma. The performance of these elements is 130 liters per hour. This is quite enough for both cars and minibuses and frame off-road vehicles. The price is in the area of two and a half thousand rubles. Also, when replacing the pump, a new fuel filter is installed. Among the good producers we would like to mention the firm "Mann". When changing the filter, pay attention to the arrow. It indicates the direction of the fuel. If you mix up in places, the injectors will receive all the dirt from the tank.

Conclusion

So, we found out what a fuel pump is, how to test it with your own hands. As you can see, the problems can concern not only the electrical, but also the mechanical part. It is not always possible to renew the serviceability of the fuel system when repairing or replacing the pump. The reason may be banal - a burnt out fuse, or oxidized contacts on the relay.