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Checking fuel pressure and the functioning of the fuel pump
 | Models 1995 g.vyp. not equipped with conventional vacuum-type fuel pressure regulator. Here, the controller is integrated into the fuel pump. In case of problems with the fuel pressure, replace the entire assembly of the fuel pump / sensor unit. |
Initial inspection If there are suspicions on deterioration of the fuel supply, first check the fuel lines for signs of leaks. Checking the operation of the fuel pump
| - Cock a lay brake and ask the assistant to turn the ignition key to ON. Themselves at this time listen to publish a pump inside the fuel tank sounds. This should be a buzz lasting about 2 seconds.
- Start the engine. Now, the buzz has to be continuous (although it will be difficult to hear because of the engine running). If there is no sound, or a defective pump or its relay or relay circuit automatic fuel shut-off (ASD) (go to n.
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Pressure check | - Relieve the fuel pressure (Section Procedure dumping fuel pressure).
- Remove the cover from the union checking fuel pressure, located in the fuel line and connect the pressure gauge port.
 | - Connect the pressure gauge to the fuel line and read his testimony at the working engine idling (model shown with an engine capacity of 5.2 liters).
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 | The examination of the fuel pressure on the models equipped with an engine capacity of 4.0 liters. |
- Start the engine and read the gauge, comparing them with those of the Specifications. Now disconnect the vacuum hose from the fuel pressure regulator. Again, when running at idle the engine, remove the reading - again it must meet the relevant requirements. Connect the hose in place.
| Models 1995 g.vyp. equipped with a built-in into the block of the fuel pump / gauge of level of fuel pressure regulator, here is possible to check only regulated fuel pressure. |
 | Models 1995 g.vyp. equipped with a built-in fuel pump inside the fuel pressure regulator. |
- If the results of measuring the pressure of fuel does not meet the requirements of the Specifications, proceed as follows:
- If the result of measurement meets the requirements of the Specifications when connected to a pressure regulator vacuum hose, but is out of range when the hose is disconnected, check the vacuum hose. If depression is present, replace the regulator (Section Check of serviceability and replacement of the fuel pressure regulator). If depression is not fixed, check the hose for breaks and blockages.
- If the pressure exceeds the limit, check the permeability of the hose (or fuel return pipe). If the permeability is not broken, replace a pressure regulator (Section Check of serviceability and replacement of the fuel pressure regulator).
- If the measured pressure is below the allowable limit, proceed as follows:
- Make sure the fuel filter is not clogged.
- Check for any kinks or blockage of the fuel hose between the fuel tank and the fuel line.
- Check the operation of the fuel pressure regulator.
- Check fuel lines for signs of leakage.
- If none of the above component failures are detected, check the condition of the fuel pump.
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The components of the fuel pressure regulator | - Connect the vacuum pump to the fuel pressure regulator. Think of the pressure gauge is not creating a negative pressure on the regulator and vacuum. With increasing depth dilution fuel pressure should drop. Compare results of measurements with data Specifications.
 | - Connect the vacuum pump to the fuel pressure regulator and measure fuel pressure without creating a vacuum at first, ..
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 | ... and then create it - if the vacuum pressure should fall.
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- Connect the vacuum hose to the regulator and check the fuel pressure when idling the engine, compare the results of measurements to requirements of Specifications. Disconnect the hose and repeat the test - pressure must jump to the maximum allowable value immediately after disconnecting the hose. If the pressure at idle speed is too high (when the hose is disconnected), connect the hose to the gauge and measure the depth of the depression in it.
- If the fuel pressure is too low, press a fuel return line and make sure the change in pressure gauge. If the pressure has not increased, either the fuel pump is faulty or broken cross fuel supply line. If the pressure is jumped, replace the fuel pressure regulator (Section Check of serviceability and replacement of the fuel pressure regulator).
| We need to make special rubber insert between the fuel line and a return line, so as steel metal lines may not be clamped to meet this test. |
- If the pressure gauge reading too high Disconnect the fuel return line and try to blow it for cross-checking. If the permeability of the line is not broken, replace the fuel pressure regulator (Section Check of serviceability and replacement of the fuel pressure regulator).
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Checking the fuel pump | - In case of problems with the operation of the fuel pump, first check the fact of its inclusion (see. P.
- If the pump does not turn on (no sound), proceed to the next item on the procedures.
- Disconnect the electrical connector of the fuel pump, and directly connected to the terminals of the battery voltage (see. Illustration below). The pump must be involved.
 | - With the wires from the kit to start the vehicle from the auxiliary power, connect the positive terminal of the battery to the terminal of the orange-black wire connector of the pump, and the negative terminal - to plug the black cable connector and listen to the sounds, talking about including a pump (shown by a model with an engine capacity of 5.2 liters ).
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- Verify the presence of voltage at the terminals of the battery supply half the pump connector with the ignition (key in position ON). If voltage is present, replace the pump (see section Cleaning and repair of the fuel tank - the general information). If no supply, check the condition of the main relay.
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Check the main relay | For a complete check of the fuel pump must be inspected as relays automatic fuel shut-off (ASD), and the relay pump. Checks both relays are produced in a similar way. |
Driving circuit fuel injection models 1995 vol., Equipped with an engine capacity of 5.2 liters (the scheme is similar to other models)  | | |
| - To test the relay, remove it from its nest in the engine compartment.
 | - Find the relay ASD (arrow) and the relay of the fuel pump in the engine compartment.
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- Remove the relay from its socket, and make sure there is battery voltage at the terminals of the socket when the ignition.
 | - Check the voltage at the terminals of the relay socket ASD.
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- If no voltage, check the pump fuse. If there is no voltage on the fuse, check the electric circuit of the pump.
- Connect the positive probe ohmmeter to terminal 86 and the negative - to the plug 85 and measure the resistance. It should be approximately 75 ohms.
 | - Measure the resistance between terminals 86 and 85; it should be approximately 75 ohms.
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- Connect the positive probe ohmmeter to terminal 30 and the negative - to the terminal 87A and re-measure the resistance. Ohmmeter should show conductivity (zero resistance).
 | - Also measure the resistance between terminals 30 and 87A; conductivity should occur.
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- Connect the positive probe ohmmeter to terminal 30 and the negative - terminal 87. Conductivity should be absent.
- Apply battery voltage to terminal 86 and ground terminal 85. Check whether in this place for continuity between terminals 87 and 30. If not, replace the relay.
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