6.4. Fuel pump and pressure of fuel
Electric chain of the fuel pump
|
1. Main relay of the fuel EPI system
2. The relay of the fuel pump (disconnecting a chain)
3. Fuel pump
4. Ignition lock
|
5. Switch of parking and neutral situation
6. Starter relay
7. Starter
8. Accumulator |
Tool kit for conducting check of fuel system
General check
| PERFORMANCE ORDER |
| 1. Check that in the fuel tank there was enough fuel. |
| 2. Check whether the fuel pump works. Include ignition and listen to a mouth of the fuel tank, you have to hear the short buzzing sound. If the pump does not work, check an electric chain of the pump. |
|
Check of pressure
| PERFORMANCE ORDER |
|
1. Lower pressure in fuel system. Disconnect a tube from the fuel filter and connect pressure measuring instrument to a tube and to the fuel filter by means of an adapter. |
| 2. Turn the ignition key in position of ON (the engine does not work, the air conditioning system is switched-off). The fuel pump has to turn on approximately for two seconds. Pressure in system has to increase and keep on one mark. Pressure should not fall below the minimum specified in technical characteristics (see subsection 6.2.). |
| 3. Start the engine and warm up it up to the normal temperature. Write down indications of the measuring instrument and compare them to technical requirements. |
4. If pressure of fuel does not conform to technical requirements:
– pressure too high – check the fuel pressure regulator, if necessary replace the regulator;
– pressure too low – replace the fuel filter. If pressure still low, check whether the injector or injectors proceeds. Check serviceability of the fuel pump. |
|
Check of an electric chain of the fuel pump
| PERFORMANCE ORDER |
|
1. If the pump does not work, check the safety locks of IGN and EFI located in the block of fuses in a motive compartment. If necessary replace safety locks, and again check whether the pump works. If the pump still does not work, check an electric chain of the pump for existence of short circuit.
|
|
|
| 2. If the pump still does not work, remove the EFI relay and check presence of tension of the accumulator on contacts of a nest of the relay. Tension on one of contacts has to move always, tension on other of contacts has to move when the ignition key is transferred to position of ON. If tension does not move on contacts, check conducting from the relay block to the accumulator. If tension moves on contacts of a nest, check relays. The main relay of the fuel EFI system is located in the block of the relay and fuses in a motive compartment (it is specified by an arrow in the drawing at the left). The relay of the fuel pump is located in the block of the relay and safety locks in interior of the car from passenger sitting (it is specified by an arrow in the drawing on the right, the Avalon models). |
| 3. If relays are serviceable, and the pump still does not work, check whether tension on the pump moves. If tension moves, so the pump is faulty, and it needs to be replaced. |
|
Check of the main relay of fuel system (EFI)
Relay of Toyota
|
|
1. Ohmmeter
2. The chain is opened
3. Ohmmeter
4. The chain is closed |
Relay of Nippondenso
|
|
1. Ohmmeter
2. The chain is opened
3. Ohmmeter
4. The chain is closed |
Relay of Bosch
|
|
1. The chain is closed
2. Ohmmeter
3. Ohmmeter
4. The chain is opened |
Remove the relay and connect a tester to contacts of 1 and 2 (Toyota relays) or 85 and 86 (Bosch relays). The chain between these contacts has to be closed, otherwise replace the relay. The chain between contacts 3 and 5 or 30 and 87 (the relay of Bosch) has to be opened.
Relay of Toyota
|
|
1. Ohmmeter
2. The chain is closed
3. Accumulator
|
When on contacts 1 and 2 the accumulator tension, a chain between contacts 3 and 5 moves it has to be closed. Otherwise replace the relay.
Relay of Nippondenso
|
|
1. Accumulator
2. Ohmmeter |
When on contacts 1 and 2 the accumulator tension, a chain between contacts 3 and 5 moves it has to be closed. Otherwise replace the relay.
Relay of Bosch
|
|
1. Accumulator
2. Ohmmeter
3. The chain is closed |
When on contacts 85 and 86 the accumulator tension, a chain between contacts 87 and 30 moves it has to be closed. Otherwise replace the relay.
