Intake System, Checking For Leaks Using V.A.G 1687 Diagnostic Tool

Intake System, Checking For Leaks Using V.A.G 1687 Diagnostic Tool

Diagnostic trouble codes (DTCs) related to fuel trim, charge pressure or mass air flow (MAF) may be caused by:
- Leaking (worn/torn) intake hoses during charge conditions
- Incorrectly torqued or improperly placed clamps on intake hoses etc. causing leaks during charge conditions







Check the charge air pressure system using the V.A.G 1687 Charge air system tester.

Special tool V.A.G 1687 Charge air system tester preliminary set-up







- Back off pressure regulator knob -2- of V.A.G 1687 fully to protect gauge when shop air supply is applied to assembly.

- Close valve -3- before gauge.

- Close valve -4- after gauge.

The shop air supply line will later be attached to the inlet of V.A.G 1687.

- Remove female fitting from tester (arrow) and install an appropriate "male" air fitting that will connect to your shop air supply line (see WARNING).

CAUTION: Use only approved air fittings to adapt shop air supply line to V.A.G 1687 tester.

Special tool V.A.G 1687/1 pressure adapter, installing (1.8L Turbo)
- Separate intake hose from Mass Air Flow (MAF) sensor assembly.







- Insert V.A.G 1687/1 pressure adapter in intake hose (black arrow) using existing clamp (as shown).
- Remove crankcase ventilation tube from intake hose at (white arrow).

NOTE:
- To help find small leaks, BEFORE pressurizing the system fill system with smoke using special tool KLI9210 and adapter KLI9210/50 as described.
- An ultrasonic detector may also be used to detect extremely small leaks where smoke may not be visible.

Special tool KLI9210 (Evaporative system leak detector), connecting to 1.8L Turbo
- Install optional fitting KLI9210/50 on hose of special tool KLI9210.







- Connect KLI9210 to V.A.G 1687/1 adapter (KLI9210 is shown attached to V.A.G 1687/1 at (arrow) on 1.8L Turbo).

Special tool KLI9210 (Evaporative system leak detector), preliminary set-up
- Connect smoke generator leads to vehicle battery.







- Turn valve to test (black arrow).
- Press smoke generator button to fill system with smoke (see instructions printed on tester).

With system filled with smoke:
- Remove smoke generator hose and connect V.A.G 1687 quickly to prevent smoke from leaking out.

Special tool V.A.G 1687, connecting to pressure adapter V.A.G 1687/1 (1.8L Turbo)

For illustrations purposes V.A.G 1687 is shown lying in the engine compartment. In practice the tool should be hung from the hood.

- Connect V.A.G 1687 quickly to prevent smoke from leaking out.







V.A.G 1687 is shown connected to V.A.G 1687/1 (black arrow)

Shop air supply will be connected to V.A.G 1687 at (white arrow)

- Perform pressure test.

Performing pressure test







With outlet hose -1- of V.A.G 1687 connected to air pressure adapter:
- Attach shop air supply line to previously installed male fitting.







- Open valve -3- between regulator valve and gauge.
- Adjust test pressure up to 0.5 bar (see CAUTION below) by turning regulator valve -2-.

CAUTION:
- DO NOT pressurize the system above 0.5 bar.
- Doing so may force oil into the intake system which can damage the engine.

- Slowly open outlet valve -4- (after gauge) to test hose connections.
- Observe pressure gauge for a drop in pressure.

NOTE: Some pressure will be lost past the throttle plate.

- Readjust test pressure to 0.5 bar ( => CAUTION listed) by turning regulator valve -2-.
- Listen for any very large intake leaks.

If smoke generator was used to fill the system with smoke:
- Inspect intake system connections for smoke at leaks.

NOTE: An ultrasonic detector may also be used to detect extremely small leaks where smoke may not be visible.

- Repair any leaks found.
- Remove tester.
- Remove plug from crankcase ventilation hose.
- Remove air pressure adapter.

With VAS 5051 diagnostic tool connected:
- Erase DTC memory.

If smoke generator was not used to fill the system with smoke:
- Apply soapy water solution or equivalent to intake system connections.

NOTE: An ultrasonic detector may also be used to detect extremely small leaks.

- Inspect intake system connections for leaks.
- Repair any leaks found.
- Remove tester.
- Remove plug from crankcase ventilation hose.
- Remove air pressure adapter.

With VAS 5051 diagnostic tool connected:
- Erase DTC memory.