Urrea 2012 Manual De Usuario Y Garantía página 8

E N G L I S H
INTRODUCTION
NOTE: Refer to specific procedures and instructions
from the vehicle manufacturers service manual. Empty
bleeder container as required. do not allow container
to overfill as brake fluid will be drawn into vacuum
pump. After bleeding, test brake performance. Clean
bleeder components with water only after use.
The use of a vacuum gauge is so often
overlooked when
condition and carryin out fault diagnosis on
internal combustion engines. Monitoring actual
manifold vacuum is invaluable when troubles
shoting engine faults. This can only be done
using a good quality vacuum gauge and with
this coupled to a hand operated vacuum pump,
it allows static testing of all types of vacuum
operated systems.
Set out on following pages are applications
that the test vacuum pump can be used for, but
it must always be remembered that these are
examples only and reference to manufacturers
repair manuals should always be made for
correct testing procedures and specifications. In
addition to this, it is always recommended that
additional tests, ie. compression test, cylinder
leakage tests, ignition turning checks etc., be
carried out to confirm indications of vacuum
gauge readings. Analysing engine mechanical
condition via manifold vacuum readings.
NOTE: the needle readings shown below, are examples
only of what may be noted.
It is important to remember that it is the action
of the needle rather than the actual reading that
is more important. Varying engine types will run
different manifold vacuum pressures, depending
on camshaft profile, valve overlap, timing, etc.,
so an exact good vacuum reading cannot be
specified. The main thing is that the needle
reading is between 16 to 21 inHg and steady.
Manifold vacuum is also affected by altitude
with the general rule being that it will drop
approximately 1 inHg for every thousand feet
8
determining mechanical
above sea level so this also must be considered
when assessing maifold vacuum actual readings.
Step 1:
Run engine until normal operating
temperature is reached.
Step 2:
Locate and connect the vacuum gauge
to a port directly on the manifold or on the
carburettor below the throttle buterfly.
Step 3:
Start and run engine at idle, observing
the gauge needle reading.
THE FOLLOWING ARE READINGS
THEAT MAY BE NOTED AND CAUSES
READING: 16-21 inHg with
needle steady.
CAUSE: Normal.
READING: When the throttle
is
released, the needle should
drop to below 5 inHg then
bounce up to approximately 25
inHg gerring back to original
reading.
CAUSE: Normal.
READING: Reading low but
steady.
CAUSE:
manifold
manifold
base gasket, split vacuum hose,
etc.
READING: Reading low but
steady.
CAUSE:
Confirm using timing light
and reset to manufacturers
specification.
READING: Reading slightly low
and fluctuathin slowly.
CAUSE: Over lean or rich
mixture. Check and reset in
accordance to manufactures
specifications.
READING: Regular fluctuation
between
readings.
CAUSE: Blown head gasket
between two adjacent cylinders
carry out cylinder leakage test.
suddenly opende then
Leaking intake
system. Faulty
gasket carburator
Retarded ignition.
normal and low