Fuel System Leak Test

WARNING: This page is about a different car, the 2010 Volkswagen Jetta, 2009 Volkswagen Jetta, 2009 Volkswagen GLI, 2008 Volkswagen Jetta, and 2008 Volkswagen GLI. However, it is still accessible from the selected car via links, so may be relevant.

Special Tools And Workshop Equipment Required

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

Test Conditions:

The "checking fuel system for leaks" test was performed. Refer to FUEL SYSTEM, CHECKING FOR LEAKS .
Connect the evaporative emissions tester KLI 9210 and the adapter hose KLI 9210/55-1 to the ventilation line.

Fig 1: Connecting Measuring Hose From Evaporative Emissions Tester KLI 9210 To Adapter For Evaporative Emission Tester KLI 9210/55-1
Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

Test Sequence:

-- Connect the evaporative emissions tester KLI 9210 to the vehicles battery.

-- Remove the right rear wheel.

-- Remove the right rear wheel housing liner. Refer to Removal and Installation .

-- Using a hose clamp up to 25 mm dia. 3094 -arrow-, clamp the connecting hose between the leak detection pump -V144- and the air filter.

Fig 2: Clamping Off Hose Between Leak Detection Pump (LDP) V144 And Air Filter

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

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

Fig 3: Identifying Evaporative Emission (EVAP) Canister Purge Regulator Components

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Observe the pressure gauge -C- and flow meter -E-. If the flow quantity decreases and pressure increases to 10 in. H2O, then the fuel system is full.

NOTE:

Depending on the level in the fuel tank, this procedure may take up to 3 minutes.

-- After the pressure has stabilized, set valve -D- to "Hold" :

After 5 minutes the pressure must not drop below 8 in. H2O (20 mbar) drop.

If the pressure no longer drops now:

-- Replace the Leak Detection Pump (LDP). Refer to Leak Detection Pump -V144- .

If the pressure is not maintained for a minimum of 5 minutes or if no pressure is built up, localize the leak as follows:

-- Fill the fuel system with smoke by setting valve -D- to "Test".

-- While the fuel system is being filled, press the smoke generator button -I- for approximately one minute.

The fuel system is now under pressure and filled with smoke.

-- Check all fuel system lines and hoses for leaking smoke. Also check the fuel tank filler tube cap.

NOTE:

Illuminate components and hoses with a strong flood light, the smoke will be more visible.

To check for leaks at accessible locations, also use a ultrasonic measuring device or commercially available leak detection spray.

Depending on how long the fault finding lasts, the smoke generator button may have to be pressed again. This ensures there is enough smoke present in the fuel system.

Remove the cover -1- to check the fuel delivery unit flange.

Fig 4: Identifying Cover With Fuel Pump Control Module J538

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Replace leaking hoses or components.

-- After completing the work, use the vehicle diagnostic tester to run the Check tank ventilation system for leaks guided function.