Fuel System Vacuum Check
Fuel System Vacuum CheckUse this procedure to measure the vacuum (negative pressure) discharge side the fuel system.
Important:
The fuel pressure/vacuum gauge assembly (gauge (1)) and the fuel pressure/vacuum gauge adapter (adapter (5)) must be cleaned before connect to the fuel line. Otherwise, foreign material adherent to the tools may damage the fuel supply pump.
1. Disconnect the fuel hose from the fuel filter housing, (fuel supply pump side).
2. Install the adapter.
Special tool
Fuel pressure/vacuum gauge adapter:
EN-47667
3. Connect the gauge (1) with hose to the adapter (5).
Special tool
Fuel pressure/vacuum gauge assembly:
J-44638
4. Loosen the air bleeding plug on the supply pump.
5. Use your hand to operate the fuel filter priming pump. Operate the pump until all the air has been bled from the system.
6. Start the engine and allow it to idle.
7. Note the gauge (1) reading. If the reading is normal, go to Step 8. If the fuel vacuum is greater than the specified value, there is a problem in the fuel system. Perform the procedures outlined below.
Standard fuel vacuum Less than 5 in Hg
- Replace the cartridge fuel filter element.
- Check the fuel delivery pipe. If it is clogged, it must be replaced.
- Remove the fuel pipe at the fuel filter inlet. Use high-pressure air forced through the fuel pipe to clean the fuel system.
CAUTION:
- Remove the fuel filler cap before applying high-pressure air.
- Do not perform this procedure if the fuel tank is nearly full (fuel approaching or flowing into the fuel filler neck). The forced air will spray fuel from the fuel filler neck.
8. Remove the gauge (1) and hose from the adapter (5).
9. Remove the adapter (5).
10. Connect the fuel hose.
11. Use your hand to operate the fuel filter priming pump. Operate the pump until all the air has been bled from the system.
12. Start the engine and allow it to idle.
13. Inspect the fuel system for fuel leakage.