Contents - Volkspage

4A.8 Fuel system: single-point injection models
the engine breather hoses are clear and
undamaged, referring to Chapter 1, Chapter 2
and Chapter 5B for further information.
2 If these checks fail to reveal the cause of the
problem the vehicle should be taken to a
suitably equipped VW dealer for testing. A
diagnostic connector is incorporated in the
engine management system wiring harness, into
which a dedicated electronic test equipment can
be plugged. This equipment is capable of
“interrogating” the engine management ECU
electronically and accessing its internal fault log.
In this manner, faults can be pinpointed quickly
and simply, even if their occurrence is
intermittent. Testing all the system components
individually in an attempt to locate the fault by
elimination is a time consuming operation that is
unlikely to be fruitful (particularly if the fault
occurs dynamically) and carries high risk of
damage the ECU’s internal components.
3 Experienced home mechanics equipped
with a tachometer and an accurately-calibrated
exhaust gas analyser may be able to check the
exhaust gas CO content and the engine idle
speed; if these are found to be out of
specification, then the vehicle must be taken to
a suitably-equipped WV dealer for assessment.
Neither the air/fuel mixture (exhaust gas CO
content) nor the engine idle speed are manually
adjustable; incorrect test results indicate a fault
within the fuel injection system.
11 Unleaded petrol -
general information and usage
Note: The information given in this Chapter is
correct at the time of writing and applies only
to petrols currently available in the UK. Check
with a VW dealer as more up to date
information may be available. If travelling
abroad consult one of the motoring
organisations (or a similar authority) for advice
on the petrols available and their suitability for
your vehicle.
The fuel recommended by VW is given in
Specifications of this Chapter.
RON and MON are different testing
standards; RON stands for Research Octane
Number (also written as RM), while MON
stands for Motor Octane Number (also written
as M M).