Touareg 2003 ➤
8-cylinder injection engine - Edition 11.2011
Test procedure
The fuel pressure regulator maintains the fuel pressure at a con‐
stant 4.0 bar.
•
Fuel pump delivery is OK.
WARNING
Fuel supply lines are under pressure! Wear eye protection and
gloves to avoid injuries and skin contact. Before loosening
hose connections, wrap a cloth around the connection. Then
release pressure by carefully pulling hose off connection.
lk
– Wrap a cloth around the threaded connection -arrow- and re‐
lease fuel pressure by quickly opening and closing connection.
– Loosen spring-type clip and disconnect fuel hose from con‐
nection on fuel rail ⇒ Item 14 (page 133) .
– Now connect pressure tester -V.A.G 1318- using adapters -
V.A.G 1318/7- , -V.A.G 1318/10- and -V.A.G 1318/13- as
shown in the illustration.
– The lever on pressure tester -V.A.G 1318- -1- points in direc‐
tion of flow.
– Always secure both hose ends with clips -2-.
– Start engine and run at idling speed.
– Measure fuel pressure. Specification: approx. 4.0 bar.
If the specification is not attained:
– Check delivery rate of fuel pumps ⇒ page 107 .
– Renew fuel pressure regulator -2-, if necessary.
If specification is attained:
– Switch off ignition.
– Now check for leaks and holding pressure. Do this by observ‐
ing pressure drop on gauge. After 10 minutes, there must be
a residual pressure of at least 3.0 bar.
If the holding pressure drops below 3 bar:
– Check pressure tester for leaks.
– Check non-return valves of left and right fuel pumps
⇒ page 111 and ⇒ page 113 .
– Switch off ignition.
When the pressure tester is removed after the test has been
completed:
2. Checking components
143
English 
