Checking fuel system pressurisation pump G6 (0.5 bar high-pressure pump) — AUDI

Checking
fuel system pressurisation pump
G6
(0.5 bar high-pressure pump)
Special tools and workshop equipment required
Lever
T10468
Pressure tester (diesel)
VAS 6551
Pressure control valve
VAS 6551/6
Fuel-resistant measuring container
Vehicle diagnostic tester
A - Checking fuel delivery rate
Observe test conditions
Chapter
.
Remove filler cap
arrow
for fuel filler neck.
WARNING
The fuel can become extremely hot. This can cause injuries.
In extreme cases the temperature of the fuel lines and the fuel can be up to 100 °C after the engine is switched off. Allow the fuel to cool down before disconnecting the lines - danger of scalding.
Wear protective gloves.
Wear safety goggles.
Risk of injury - fuel system operates under high pressure.
To reduce the pressure in the fuel system, wrap a clean cloth around the connection and carefully loosen the connection.
Version 1:
Disconnect fuel supply line
1
. Disconnecting plug-in connectors
Chapter
Version 2:
Disconnect fuel line
2
. Disconnecting plug-in connectors
Chapter
All vehicles (continued):
Connect
pressure tester (diesel)
VAS 6551
to fuel supply line with
hose
VAS 6551/2
.
Attach
pressure control valve
VAS 6551/6
and hold end of hose into fuel-resistant measuring container.
Switch on
pressure tester (diesel)
VAS 6551
item 1
by pressing
On/Off
button.
Note
To measure the fuel delivery rate, pressure must first be built up in the fuel supply line; the fuel pump must then operate against this pressure during the measurement. This pressure can be built up using the
pressure control valve
VAS 6551/6
as follows:
Open cut-off valves
A and B
.
Levers must point in direction of flow.
Caution
Risk of fuel escaping.
Cut-off valve
C
must be closed.
The lever should point perpendicular to direction of flow.
Connect
vehicle diagnostic tester
.
Switch on the ignition and select the following menu options on the vehicle diagnostic tester:
Vehicle self-diagnosis
Engine electronics
Basic setting
Checking fuel system pressurisation pump
Press
Start
: The fuel pump will start running.
Build up pressure in fuel system by turning adjuster screw
1
on
pressure control valve
VAS 6551/6
until correct pressure is reached.
Specification: 0.5 bar
From this point on, do not turn adjuster screw
1
.
Press
Stop
.
Drain measuring container.
For measurement, press
Start
again and let fuel pump run for 15 seconds.
Press
Stop
after 15 seconds.
Check amount of fuel delivered in measuring container.
Specification: minimum delivery rate 200 cm
3
/15 sec.
If the minimum delivery rate is attained:
Fuel supply line and fuel pump are OK.
However, there may be a fault in the return line or fuel filter.
If minimum delivery rate is not achieved, check for the following causes:
Fuel pump in fuel tank faulty.
Fuel line crushed.