MAHLE RTI ESX-2 - Manual (Page 26)

Page 25
Vehicle Diagnostics
Leakdown Test - PFI, TBI, CIS
1. Verify that Steps 1-9 from the appropriate fuel system setup have been completed.
2. Verify that the engine is running and check all connections for leaks.
3. Turn off the vehicle.
4. Note the pressure reading on the ESX Fuel Pressure gauge. The pressure should stay
the same or increase marginally due to heat expansion (refer to the manufacturer’s
specifications for a CIS system, the pressure may initially drop).
If there is a pressure drop, this indicates a leak in the system. Re-pressurize the system
to isolate the leak. Use steps below to re-pressurize fuel system.
A. Press and hold the Start button.
B. Turn the ESX Pressure Control regulator clockwise until the ESX Fuel
Pressure gauge displays 3/4 of the pressure noted in Step 4.
C. Release the Start button.
D. Press the - button to decrease time until the LED timer displays five minutes.
E. Press the Leak Test button on the ESX Keypad.
If needed, use the steps above to re-pressurize the fuel system during the
Leakdown Test.
5. With the system re-pressurized, locate the pressure line adapter closest to the Tee
adapter and the vehicle fuel tank. Bend the pressure line adapter in half and squeeze
tightly. If the pressure stabilizes, this indicates a leak in either the pressure fuel line or
a bad one-way check valve in the vehicle fuel pump.
6. Locate the return line adapter closest to the vehicle pressure regulator. Bend the return
line in half and squeeze tightly. If the pressure stabilizes, then this indicates a leak in the
vehicle pressure regulator. This problem should be resolved by the cleaning process
because it is generally dirt related. However if there is fuel in the vacuum line from the
regulator, this indicates a leaking diaphragm.
7. If the steps above do not stop the leak, bend both adapters simultaneously. If a
leakdown is still present, the leak is probably the result of one or more injectors leaking.
This problem should be resolved by the cleaning process because it is generally dirt
related.
8. Close the valve on the Tee adapter and use a shop rag at all connection points before
disconnecting. Disconnect the battery leads, hoses, and adapters. Reconnect all of the
vehicle fuel lines and reinstall the vehicle fuel cap.