Checking fuel system pressurisation pump G6 - A5/S5/RS 5 up to model year 2011, A4 up to model year 2012 — AUDI

Checking
fuel system pressurisation pump
G6
- A5/S5/RS 5 up to model year 2011, A4 up to model year 2012
Special tools and workshop equipment required
Remote control
V.A.G 1348/3A
for V.A.G 1348 with adapter cable
V.A.G 1348/3-3
Adapter
V.A.G 1318/12
for S5 (8-cylinder)
Adapter set
V.A.G 1318/17A
for S5 (8-cylinder)
Auxiliary measuring set
V.A.G 1594C
Pressure tester
VAS 6550
with hoses
VAS 6550/1
and
VAS 6550/2
Pressure control valve
VAS 6550/4
Fuel-resistant measuring container
A - Checking fuel delivery rate
Observe test conditions
Chapter
.
Remove rear seat bench
General body repairs, interior
Rep. gr.
72
Rear seats; Removing and installing seat bench/individual seats
.
Unscrew cover for flange
arrows
.
Unplug electrical connector
1
on flange.
Note
Disregard
item 2
.
To do so, slide catch
1
upwards
arrow A
and press release catch inwards
arrow B
.
Connect
remote control
V.A.G 1348/3A
for V.A.G 1348 to contact
1
using adapter cable
V.A.G 1348/3-3
and test lead from
auxiliary measuring set
V.A.G 1594C
.
Tape off 2nd connector contact of adapter cable
V.A.G 1348/3-3
with insulating tape
arrow
to prevent short circuits.
Connect contact
5
to vehicle body (earth) using a test lead from
auxiliary measuring set
V.A.G 1594C
.
Move switch of
remote control
V.A.G 1348/3A
for V.A.G 1348 to front of engine compartment.
Remove plenum chamber cover (centre)
General body repairs, exterior
Rep. gr.
50
Plenum chamber partition panel; Removing and installing plenum chamber cover
.
Release retainer
arrow A
and open cover
arrow B
.
Connect crocodile clip to
jump start socket
U6
item A
in
terminal 30 wiring junction 2
TV22
located in plenum chamber.
Release and open tank flap.
Remove filler cap
2
for fuel filler neck
1
.
Note
Disregard
item 3
.
WARNING
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.
Vehicles with 4-cyl. engine:
Disconnect fuel line
2
. Disconnecting plug-in connectors
Chapter
Vehicles with 6-cyl. FSI and TFSI engines:
Release hose clip and detach fuel line
1
.
Connect
hose
VAS 6550/1
to fuel supply line with test hose
1
and secure with hose clips
2
.
S5 with 8-cyl. engine:
Remove engine cover panel
arrows
.
Disconnect fuel line
arrow
.
Using adapter
V.A.G 1318/12
, connect hose
V.A.G 1318/17A
to fuel line
1
.
RS 5:
Remove engine cover panel
arrows
.
Push down protective sleeve
1
and disconnect hose connector
2
Chapter
.
All vehicles (continued):
Connect
pressure tester
VAS 6550
to fuel supply line with
hose
VAS 6550/2
.
Attach
pressure control valve
VAS 6550/4
and hold end of hose into fuel-resistant measuring container.
Note
Illustration shows measuring equipment connected on a 4-cyl. engine as an example.
Switch on
pressure tester
VAS 6550
item 1
by pressing
On/Off
button.
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.
Note
To measure the fuel delivery rate, pressure must first be built up in the fuel line; the fuel pump must then operate against this pressure during the measurement. This pressure can be built up using the
pressure tester
VAS 6550
as follows:
Press remote control switch; fuel pump will start running.
Build up pressure in fuel system by turning adjuster screw
1
on
pressure control valve
VAS 6550/4
until correct pressure is reached.
Specification: 4.0 bar
Let go of remote control switch.
From this point on, do not turn adjuster screw
1
.
Drain measuring container.
Press remote control switch for 15 seconds.
Compare amount of fuel delivered with minimum delivery shown in diagram (cm
3
/15 sec.).
Note
Voltage at fuel pump with engine stationary and pump running is approx. 2 volts less than battery voltage.
If the minimum delivery rate is attained:
Fuel delivery unit with with fuel filter, fuel pressure regulator and fuel supply line OK.
If minimum delivery rate is not achieved, check for the following causes:
Fuel delivery unit is defective.
Fuel filter is blocked.
Fuel pressure regulator is defective.
Fuel supply line crushed.
Note
To find the precise cause of the fault, a pressure test must be performed on the fuel supply line as described below.
B - Pressure test on fuel supply line
Leave measuring equipment connected in the same way as for measuring the fuel delivery rate.
Switch on
pressure tester
VAS 6550
item 1
by pressing
On/Off
button.
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.
Press remote control switch; fuel pump will start running.
When fuel emerging is free of bubbles, close cut-off valve
B
to allow fuel pressure to build up.
The lever should point perpendicular to direction of flow.
Read fuel pressure off
pressure tester
VAS 6550
:
Specification: 5.0 ... 8.0 bar
If specification is attained although fuel delivery rate was not OK:
Blocked fuel filter or crushed fuel supply line.
If specification is not attained:
Fuel delivery unit or fuel pressure regulator (on fuel filter) defective.
C - Checking residual pressure
Check system for leaks and check residual pressure by watching drop in pressure on
pressure tester
VAS 6550
:
After 10 minutes pressure should still be at least 3 bar.
If the residual pressure drops below 3 bar:
Check fuel lines and their connections for leaks.
Non-return valve in fuel pump is leaking, renew fuel delivery unit
Chapter
.
Assembling
Installation is carried out in the reverse order; note the following:
The ignition must be switched off.
Remove remote control.
Note
Before removing the pressure tester
1
, release the fuel pressure by opening the cut-off valves
B, C
and allowing fuel to drain off into a measuring container.
Detach
pressure tester
VAS 6550
together with connection leads.
Connect fuel supply line:
Vehicles with 6-cyl. FSI and TFSI engines:
Secure fuel supply line with hose clip (refer to
Electronic parts catalogue
) and then pull to check that line is properly secured.
Vehicles with 4-cyl. engine and RS 5:
Connect fuel supply line, making sure it engages audibly.
Press fuel supply line in again and then pull to check that plug-in connector is correctly engaged.
S5 with 8-cyl. engine:
Secure fuel line to fuel rail
Rep. gr.
24
Injectors; Exploded view - fuel rail with injectors
.
All vehicles (continued):
Install cover for flange
Fig.
.
Install rear seat bench
General body repairs, interior
Rep. gr.
72
Rear seats; Removing and installing seat bench/individual seats
.