Fuel System, Checking For Leaks: Notes

Special tools and workshop equipment required 

• Evaporative Emission Tester -KLI 9210-
• Adapter for Evaporative Emission Tester KLI 9210/55-1
• Vehicle Diagnostic Tester
• Hose Clamps Up to 25 mm Dia. -3094-

The connectors for the fuel, vacuum and ventilation lines are color coded. There is either a colored dot on the connector or the release button is the corresponding color.

Connector	Colored Mark on the Connector
Fuel supply	Black
Fuel return	Blue
Ventilation	White, Beige
Vacuum	Green

Test Conditions 

• A leak was detected by the leak detection pump -V144-.
• Guided fault finding was performed using the vehicle diagnostic tester.

Evaporative Emissions Tester -KLI 9210- Preparation

-- Check the evaporative emissions tester -KLI 9210- to determine whether there is enough fluid in the smoke generator.

-- Set the valve -D- to "Hold".

-- Open the nitrogen bottle -H-.

-- Connect the measuring hose -G- to the self-test connection -B-.

-- Set the valve -D- to "Test".

-- Using the pressure reducer -J-, adjust the pressure to 10 in. H2O (25 mbar).

-- Set the valve -D- to "Hold".

-- The pressure must now be maintained a minimum of 2 minutes. If the pressure is not maintained, check the tester.

Fuel System, Checking for Leaks 

-- Connect the adapter for evaporative emission tester -KLI 9210/55-1 to the ventilation line -A- as shown. (color identification: white)

-- Connect the measuring hose -G- from the evaporative emissions tester -KLI 9210- to the adapter for evaporative emissions tester KLI 9210/55-1.

-- Set the valve -D- to "Hold".

-- Connect the vehicle diagnostic tester to the vehicle.

-- Start the engine and run at idle speed.

-- Select Guided Functions  on the vehicle diagnostic tester.

-- Select "Check tank ventilation system for leaks" guided function.

-- Activate the test.

-- While the test runs, observe the pressure gauge on the evaporative emissions tester -KLI 9210-.

• The leak detection pump must pump the fuel system pressure up to at least 7 in. H2O (18 mbar).

If the minimum pressure is not reached, but the pressure reached does not decrease: 

-- Turn the ignition off and perform a pressure retention test, refer to PRESSURE RETENTION TEST . If no decrease in pressure is observed: Check the leak detection pump vacuum supply. Refer to LEAK DETECTION PUMP, CHECKING VACUUM SUPPLY .

If the minimum pressure is not reached and the pressure reached decreases immediately: 

-- Clamp off the hose to the EVAP canister purge regulator valve 1 -N80- using a hose clamp up to 25 mm dia. -3094- -arrow-.

-- Repeat the test. If the minimum pressure is not reached: Replace the EVAP canister purge regulator valve 1.

If the minimum pressure is not reached again and the pressure reached decreases immediately: 

-- There is a leak in the fuel system, perform the "fuel system leak test". Refer to FUEL SYSTEM LEAK TEST .

If the minimum pressure is reached, turn the ignition off.

The valve in the leak detection pump is now closed and the pressure is maintained.

-- Observe the pressure gauge:

If the pressure does not decrease, perform a pressure retention test to locate any possible pinhole leaks. Refer to PRESSURE RETENTION TEST .

If the pressure decreased, clamp off hose to the EVAP canister purge regulator valve 1 using a hose clamp up to 25 mm dia. -3094- -arrow-.

-- If pressure now no longer falls, replace the EVAP canister purge regulator valve 1.

If the pressure still decreases, perform the "fuel system leak test". Refer to FUEL SYSTEM LEAK TEST .