Checking delivery pressure and tandem pump for leaks - engine codes BJB, BLS, BSU — VW

Checking delivery pressure and tandem pump for leaks - engine codes BJB, BLS, BSU
Checking delivery pressure
Anchor
Checking for internal leaks
Anchor
Checking delivery pressure
Special tools and workshop equipment required
Vehicle diagnosis, testing and information system
VAS 5051B
Diagnosis cable, 3 m
VAS 5051B/2
Tandem pump tester
VAS 5187
Torque wrench
V.A.G 1331
Test prerequisites
Coolant temperature must be at least 85 °C.
Unit injectors OK.
Fuel filter and fuel lines must not be blocked.
The non-return valve in the fuel supply hose must be OK.
Procedure:
Unscrew plug
arrow
.
Connect
tandem pump tester
VAS 5187
as shown.
Start engine and run at idling speed.
Connect
vehicle diagnosis, testing and information system
VAS 5051B
and select
“Vehicle self-diagnosis”
mode.
Press button
“01 - Engine electronics”
on display.
Press diagnostic function
“08-Read measured value block”
.
Enter display group
“1”
using numeric key pad and confirm entry with "Q“ key.
Read off idling speed in display field
“1”
.
Increase speed to 4000 rpm.
Observe pressure displayed on pressure gauge.
Specification: min. 7.5 bar
If the specification is not attained:
Using a hose clamp, clamp off return line between fuel filter and tandem pump.
Increase speed to 4000 rpm.
Check displayed pressure on pressure gauge.
Specification: min. 7.5 bar
If specification is now obtained:
Pressure loss at unit injectors.
Renew O-rings for unit injectors.
If the specification is not attained:
Renew tandem pump
Chapter
.
Note
After removing pressure gauge, tighten sealing plug to 25 Nm. The seal must be renewed.
Checking for internal leaks
Note
The tandem pump must be checked for internal leaks between fuel side and oil side after reinstalling a used tandem pump, for example after replacing or repairing a cylinder head and/or when installing a "short" engine. In the event of a leak, it is possible for the fuel to mix with the oil which may cause engine damage.
Special tools and workshop equipment required
Charge air system tester
V.A.G 1687
Procedure:
Detach fuel supply hose (white marking) and fuel return hose (blue marking) from tandem pump.
Seal fuel return connection on tandem pump with blind plug. Secure blind plug with spring-type clip.
Prepare
charge air system tester
V.A.G 1687
as follows:
Unscrew pressure control valve
2
completely and close valves
3
and
4
.
Connect test connection
5
to fuel supply connection of tandem pump using commercially available compressed air connection and a section of fuel hose. Secure by means of spring-type clip.
Note
To turn the pressure regulating valve
2
the knob must be pulled upwards.
Connect compressed air hose
1
(compressed air supply) to
charge air system tester
V.A.G 1687
.
Note
If water is in inspection glass, drain via drain screw
6
.
Open valve
3
.
Adjust pressure to 1.0 bar with pressure control valve
2
.
Caution
The maximum test pressure is 1.3 bar and this must not be exceeded.
Open valve
4
and wait until test circuit is full. If necessary, regulate pressure to 1.0 bar.
Close valve
3
to maintain pressure and observe pressure drop over a period of 1 minute.
If the pressure does not drop the tandem pump can be reused, if the pressure drops the tandem pump must be renewed.