Innova 3551 Manual Del Propietário página 10

Using Your Timing Light
4. Note the degrees advance indicated by
the Advance Control Knob's calibrated
dial, and compare this value with the
manufacturer's specification for mech-
anical or centrifugal timing advance for the
rpm specified.
■
If the position of the rotating timing
mark does not change during the
mechanical/centrifugal advance
check, the mechanical weights
associated with your vehicle's
mechanical advance mechanism (if
equipped) may be rusted or binding.
5. Repeat the test, as needed, for all engine
speeds specified by the manufacturer's
instructions.
Checking Vacuum Timing Advance
NOTE
A vacuum pump equipped with a vacuum
gauge is needed to check vacuum advance.
1. With the engine off, disconnect the
vacuum hose from the distributor's
vacuum advance port. Plug the vacuum
hose securely.
2. Connect the vacuum pump to the
distributor's vacuum port. Do not apply
vacuum at this time.
3. Start the engine and perform INITIAL
(BASE) TIMING CHECK as previously
described. Record the degree(s) of initial
(base) timing.
8
4. Using the vacuum pump, apply the
manufacturer's specified amount of
vacuum to the distributor's vacuum port.
5. Aim the timing light at the timing marks
and rotate the Advance Control Knob
clockwise until the timing marks are
realigned to the initial (base) timing mark
as recorded in step 3.
6. The difference between the reading
obtained in step 3 (initial (base) timing)
and the value obtained in step 5 is the
vehicle's vacuum advance. Compare this
value with the manufacturer's specifications
for vacuum advance.
7. Repeat the test, as needed, for each
amount of vacuum specified by the
manufacturer's instructions.
8. Turn off the ignition and disconnect the
timing light and vacuum pump from the
engine. Unplug and reconnect the vacuum
hose to the distributor's vacuum port.
Checking Vacuum/Electronic Retard and
Electronic Advance
The procedures for checking vacuum/electronic
retard and electronic advance vary between
vehicles and manufacturers. Refer to your
vehicle's service manual for specifications and
procedures.
A vacuum pump equipped with a vacuum
gauge is required to check vacuum retard.