AUDI A4 1999 B5 / 1.G AWM Engine Charge Pressure Leak Test Workshop Manual

21-16


Charge pressure leak test with
VAG 1687

Intake system, checking for leaks using
VAG 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 VAG 1687 Charge air
system tester.
Special tool VAG 1687 Charge air system tester preliminary set-up

- Back off pressure regulator knob -2- of VAG 1687 fully to protect gauge
when shop air supply is applied to assembly.
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The shop air supply line will later be attached to the inlet of VAG 1687. - Close valve -3- before gauge.
- Close valve -4- after gauge.
- Remove female fitting from tester (arrow) and install an appropriate
"male" air fitting that will connect to your shop air supply line (
WARNING!).
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21-17

WARNING!

Use only approved air fittings to adapt shop
air supply line to VAG 1687 tester.

Special tool VAG 1687/1 pressure adapter,
installing (1.8L Turbo)

- Separate intake hose from Mass Air Flow (MAF)
sensor assembly.

Special tool VAG 1687/1 pressure adapter, installing (2.7L BiTurbo)
Repair Manual, Maintenance; Air cleaner housing, cleaning; Air cleaner element, replacing
- Insert VAG 1687/1 pressure adapter in intake hose -black arrow- using
existing clamp (as shown).
- Remove crankcase ventilation tube from intake hose at -white arrow-.
- Remove upper air cleaner housing and hoses to intake manifold as
necessary

- Insert VAG 1687/1 pressure adapter in intake hose -white arrow- using
existing clamp (as shown).
- Disconnect engine crankcase ventilation hose from intake manifold -
black arrow-.
-
Plug intake manifold fitting (for crankcase ventilation hose) with
appropriate hose and metal plug using clamps supplied with VAG
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1687/1 special tool kit.
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21-18

Note:

To help find small leaks, BEFORE pressurizing
the system fill system with smoke using special
tool KLI9210 and adapter KLI9210/50 as
described on Page 21
-18
.

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 LKI9210/50 on hose of
special tool KLI9210.

Special tool KLI9210 (Evaporative system leak detector), connecting
to 2.7L BiTurbo - Connect KLI9210 to VAG 1687/1 adapter (KLI9210 is shown attached
to VAG 1687/1 at arrow on 1.8L Turbo).
- Install optional fitting LKI9210/50 on hose of special tool KLI9210.

-
Connect KLI9210 to VAG 1687/1 adapter (KLI9210 is shown attached
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to VAG 1687/1 at arrow on 2.7L BiTurbo).
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21-19

Special tool LKI9210 (Evaporative system
leak detector), preliminary set-up

- Connect smoke generator leads to vehicle
battery.

With system filled with smoke:
Special tool VAG 1687, connecting to pressure adapter VAG 1687/1
(1.8L Turbo)
For illustrations purposes VAG is shown lying in the engine compartment.
In practice the tool should be hung from the hood. - Turn valve to test -black arrow-.
- Press smoke generator button to fill system with smoke (see
instructions printed on tester).
- Remove smoke generator hose and connect VAG1687 quickly to
prevent smoke from leaking out Page 21
-19
.
- Connect VAG 1687 quickly to prevent smoke from leaking out.

VAG 1687 is shown connected to VAG 1687/1 -black arrow-
Shop air supply will be connected to VAG 1687 -at white arrow-
- Perform pressure test Page 21
-21
.
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21-20

Special tool VAG 1687, connecting to
pressure adapter VAG 1687/1 (2.7L BiTurbo)
For illustrations purposes VAG is shown lying in
the engine compartment. In practice the tool
should be hung from the hood.

- Connect VAG 1687 quickly to prevent smoke
from leaking out.

VAG 1687 is shown connected to VAG 1687/1 -black arrow-
Shop air supply will be connected to VAG 1687 -at white arrow-
- Perform pressure test Page 21
-21
.
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21-21

Performing pressure test:

- With outlet hose -1- of VAG 1687 connected to air pressure adapter:
- Attach shop air supply line to previously installed male fitting Page
21
-16
.

CAUTION! - Open valve -3- between regulator valve and gauge.
- Adjust test pressure up to 0.5 bar ( CAUTION below) by turning
regulator valve -2-.
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.
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21-22

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

- Readjust test pressure to 0.5 bar ( CAUTION
above) 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.
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