Checking fuel system pressurisation pump G6 - vehicles with 4-cyl. engine — AUDI

Checking
fuel system pressurisation pump
G6
- vehicles with 4-cyl. engine
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
Hand-held multimeter
V.A.G 1526 E
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
.
Move front seats all the way forwards.
Release and open tank flap.
Clean area around fuel filler neck.
Remove filler cap
2
for fuel filler neck
1
.
Note
Disregard
item 3
.
Front-wheel drive vehicles without high-voltage system:
Remove rear seat bench
General body repairs, interior
Rep. gr.
72
Rear seats; Removing and installing seat bench/individual seats
.
Unclip cover
1
for fuel tank flange at retainers
arrows
using
removal wedge
3409
.
Release retainer catch and unplug electrical connector
1
on flange.
Note
Disregard
item 2
.
Vehicles with high-voltage system:
Remove rear shelf
General body repairs, interior
Rep. gr.
70
Passenger compartment trim panels; Removing and installing rear shelf
.
Remove luggage compartment floor
General body repairs, interior
Rep. gr.
70
Luggage compartment trim panels; Removing and installing luggage compartment floor
.
Fold down rear seat backrests.
Remove subwoofer
Communication
Rep. gr.
91
Sound system; Removing and installing
subwoofer
R211
.
Remove nuts
arrows 1 ... 5
and detach flange cover
6
.
Release retainer catch and unplug electrical connector
arrow
on flange.
All vehicles with front-wheel drive (continued):
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)
A
using a test lead from
auxiliary measuring set
V.A.G 1594C
.
Connect crocodile clip to positive battery terminal
“+”
item B
.
Vehicles with four-wheel drive:
Remove rear seat bench
General body repairs, interior
Rep. gr.
72
Rear seats; Removing and installing seat bench/individual seats
.
Unclip cover
1
for fuel tank flange at retainers
arrows
using
removal wedge
3409
.
Release retainer catch and unplug electrical connector
1
on flange (right-side).
Note
Disregard
item 2
.
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
2
to vehicle body (earth)
A
using a test lead from
auxiliary measuring set
V.A.G 1594C
.
Connect crocodile clip to positive battery terminal
“+”
item B
.
All vehicles (continued):
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.
Disconnect fuel line
1
. Disconnecting plug-in connectors
Chapter
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.
Switch on
pressure tester
VAS 6550
item 1
by pressing
On/Off
button.
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 control valve
VAS 6550/4
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.
Press remote control switch.
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
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 fuel supply line is OK.
If minimum delivery rate is not achieved, check for the following causes:
Fuel delivery unit 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.
Leave
remote control
V.A.G 1348/3A
for V.A.G 1348 connected.
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.
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: at least 6.0 bar
If specification is attained although fuel delivery rate was not OK:
Fuel filter integrated in fuel delivery unit blocked or fuel supply line crushed.
If specification is not attained:
Fuel delivery unit is 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.
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, making sure it engages audibly.
Press fuel supply line in again and then pull to check that plug-in connector is correctly engaged.
Vehicles without high-voltage system:
Install rear seat bench
General body repairs, interior
Rep. gr.
72
Rear seats; Removing and installing seat bench/individual seats
.
Vehicles with high-voltage system:
Install luggage compartment floor
General body repairs, interior
Rep. gr.
70
Luggage compartment trim panels; Removing and installing luggage compartment floor
.
Install rear shelf
General body repairs, interior
Rep. gr.
70
Passenger compartment trim panels; Removing and installing rear shelf
.
Tightening torques
Chapter
“
Exploded view - fuel delivery unit/fuel gauge sender, vehicles with high-voltage system
”
Communication
Rep. gr.
91
Sound system; Overview of fitting locations - sound system