Car Fuel pump

Fuel pump is necessary for fuel delivering from the tank to the engine. Depending on fuel there are diesel and petrol pumps. Fuel pump is situated on the tank or inside it. More often it is built into the control system. There are many fuel pump models, but the most widespread are in-line and dispenser pumps. In older car models more often were used roller-cell and rotary pumps. When there is a very high pressure, the best choice is a trochoid pump. In order pressure not to change and cable not to break, there is a back-pressure valve.

Defects in fuel pumps are often met. Its wear may result in a mechanical damage. You can detect it by a loud noise. If the problems appear when the engine is warmed up, this confirms that the pump is damaged, because after you switch engine with damaged pump off, pressure drops. Very often fuel filter is obstructed or there is a problem with inlet manifold. Pump’s function may be checked with manometer.

If it necessary to check the fuel pump, pay attention to the fuel filter state. Also there is sense to change all the sealants when you substitute the pump. As damaged petrol or diesel pump may result in car damage, it is necessary to check your car if there are no breakdowns of another important details. In our online shop there is a wide range of spare car parts for many car models. Here you will find brake pads, fuel filters, stub axles, air filters, mudguard fenders, spark plugs, head lights and brake gear boosters. Using the search function you will find necessary part.

How to detect fuel pump failure

In case of indirect symptoms of the component malfunction, check pressure. First disconnect the fuse of the component, and run the engine at idle speed. The readings are taken after the engine stalls due to the lack of fuel. The priming pump pressure should be 2.5–4 MPa. Reaching this value should take no more than two seconds.

If the pressure is measured at idle speed, the pressure gauge needle should not fluctuate much. Otherwise, the component is clogged.

The pressure level should remain also after the ignition is switched off. Falling pressure is the evidence of the incorrectly operating back-pressure valve of the pump, or of depressurized system.

The amount of fuel that flows through the injectors should also be checked. To do this, disconnect the fuel line, and drain fuel from the pump into a measuring vessel. Technical documentation contains the information about the amount of fuel flow rate in a minute's time.

To rule out wiring problems, connect a voltmeter. The optimum voltage is 12 V. It may be measured by connecting the contacts to a 12 V lamp.

If the pump does not respond, check the wiring and the fuse.

If high quality fuel is used, the component will last two to five years on the average. In other words, pump should be replaced after every 200 thousand kilometers of mileage.

You may notice that the fuel pump may need diagnostics by the following symptoms:

• the engine has lost power;
• unusual sound is heard during engine operation;
• pressure in the fuel system decreased;
• the engine starts with difficulty;
• when the accelerator is pressed, the vehicle gains speed slowly;
• mechanical damage;
• the component is clogged or fouled;
• the pressure regulator operates incorrectly;
• relay of the component is faulty;
• shorted or faulty wiring;
• the component is worn out.

The reasons of fuel pump malfunction

Failure of the fuel pump may be due to several reasons. The most common reason is using low grade fuel. Iron-containing additives and resins destruct elements of the component, and accelerate formation of deposit on their surface. All this eventually results in fuel pump malfunction.

Jamming of individual components of the unit may be caused by accumulation of dirt trapped inside the system during fueling, or due to loss of its integrity. Therefore, to prolong the service life of the component, it is important to constantly monitor cleanliness of the fuel tank. The use of clogged or defective filters creates increased loads on the fuel pump, and results in its premature failure.

Many malfunctions of the unit are caused by continuous use of low grade fuel. Due to the lack of fuel, air enters the fuel system, causing destruction of its components. Besides, in rainy weather, water is condensed in an unfilled fuel tank. It is dangerous not only for accelerated corrosion. The water infiltrating inside washes away the lubricating fuel film from the component's surfaces, causing their increased friction and overheating. In winter, the risk of component freezing increases.

Fuel pump replacement and repair

Repair only allows removing contamination from the component. For cleaning, remove the mesh and remove the dirt with a special liquid. Injectors should also be cleaned.

If the component has been mechanically damaged, it should be replaced immediately.