Troubleshooting the fuel pump

One relay energizes the electric fuel pump. Starting from the start-up period, the pump supplies fresh fuel to the injectors. The second relay comes into action only when the engine is stopped with the ignition on (the control unit no longer receives speed pulses). The relay then interrupts the current supply in the PCM by means of a safety circuit. Thanks to this, for example, there is no leakage of fuel after an accident. Previously, checking the fuel pump was the prerogative of the workshop. When troubleshooting, it is better to limit yourself to the following points.

PROCEDURE

Disconnect the battery wires and... ...disconnect the pressure pipe from the distribution tube. Prepare rags for leaking gasoline. Since the fuel system is pressurized, gasoline flows out even when the engine is stopped. If the connection remains dry, briefly switch on the ignition without operating the starter. If the pump does not run, check the fuse or safety relay. If the connection continues to be dry, check the pump relay. Now the fuel pump should work. Otherwise, remove the lining under the rear seat and «treat» the pump housing by gently hitting with a small hammer - sometimes this helps. Nearly silent: 12 volt electric pump: 1 - Current connection, 2 - Hydraulic connection (supply pipeline), 3 - Check valve, 4 - Carbon brushes, 5 - Armature of the motor with a permanent magnet, 6 - pump rotor, 7 - Hydraulic connection (drain pipe), A - injection chamber, B - 12 Volt pump motor, C - Inlet / drain chamber. When doing this, also check that the connection terminals are firmly seated on the contacts. If this does not work on him, check with a diode tester (a conventional test lamp can damage the control device) the presence of tension. Don't forget to turn on the ignition first. If there is voltage, there is a defect in the pump or a break in the connecting wire. Your chances of repairing defects in the fuel pump are naturally slim, so your best bet is to install a new pump. If the pump is running, but there is no fuel in the discharge pipe, then it is contaminated or «only» broken fuel filter or fuel line.