Car High pressure fuel pump

How to detect the injection pump failure

Diagnosis of the fuel injection pump is made on a special test bench simulating the engine operation, therefore it should be performed at a service station. First, the starting fuel supply and volumetric fuel supply are measured in various engine operation modes, and then the obtained values are compared with the values specified by the pump manufacturer in the technical documentation. If they do not coincide, the part requires to be repaired or replaced.

You may identify that the injection pump requires an inspection, by the following symptoms:

• increased fuel consumption;
• loss of engine power;
• unstable operation of the power unit at low rpms;
• sudden engine stalls at idling speed;
• black smoke from the exhaust pipe;
• slipping off of the timing belt;
• fuel stains on the injection pump surface;
• hindered engine start;
• abnormal sounds from the engine compartment while the engine is running;
• the smell of gasoline in the passenger and engine compartments.

Causes of the injection pump failure

The most frequent cause of malfunctions in fuel injection pumps is usage of poor quality fuel. The abrasive particles and moisture contained in it have a disruptive impact on the pump components, leading to increased wear of the plunger-and-barrel assembly and corrosion of the metal components. Aggressive chemicals and substandard additives destruct the part sealing elements.

Eventually, products of wear of the injection pump components, and dirt getting inside the system with fuel cause jamming of the valves and the fuel rail. To prevent this, replace the fuel filters in due time, and flush the fuel system at a service station. Special cleaning additives can be also used, you should add them to the fuel tank in the amount specified in the instructions.

Unstable voltage in the car electrical circuit can lead to malfunctions of the pump electrical components. Loss of tightness of the housing and damage of the insulating sheath of wires result in oxidation of the contacts or a short circuit.

Repair of the injection pump

The part repair requires the use of special tools, test benches, appropriate software, and should be done by qualified specialists. Restoration works are performed in several steps. First, the pump is thoroughly cleaned from dirt and carbon deposits, then dried with the help of compressed air. Then the assembly is demounted and the components are checked for damage. Defective injection pump components are replaced with new ones. After the reassembly, the unit undergoes comprehensive testing.

Replacement of the injection pump

You can install a new fuel injection pump on your own. The procedure may considerably vary depending on the vehicle brand and model. Therefore, when doing the replacement by yourself, you have to follow the instructions provided by the automaker in the vehicle technical documents. During the work, be sure to mark the sequence of connection of the terminals and hoses, as well as the position of the pulleys, in order to prevent mistakes during the re-installation. At the end of the procedure, do not forget to adjust the ignition timing and the vacuum valve position.