2. Note the pressure at which the needle
valve opens on gauge 1. The valve
should open between 2200 and 3200 psi
(15,158 and 22,048 kPa). The opening
and closing action should be sharp and
produce a normal finely atomized spray
pattern.
If the valve opening pressure is below
2200 psi (15,158 kPa) and/or atomization
is poor, the cause is usually a weak
valve spring or poor needle valve seat.
If the valve opening pressure is within
2200-3200 psi (15,158-22,048 kPa,), pro-
ceed to check for spray tip leakage as
follows:
A. Actuate pump lever 1 several times
Figure 11C-17. Checking Needle Valve
and hold the pressure at 1500 psi
Lift
(10,335 kPa) for 15 seconds.
1. Zero the indicator by placing the bot-
B. Inspect the spray tip for leakage.
tom surface of the plunger assembly on a
There should be no fuel droplets, al-
flat surface and zero the indicator dial.
though a slight wetting at the spray
tip is permissable.
2. Place the spray tip and needle valve
assembly tight against the bottom of the
NEEDLE VALVE LIFT TEST. To measure
gauge with the quill of the needle valve
the needle valve lift, use tool J 9462-01
in the hole in the plunger.
as follows (see Figure 11C-17):
3. While holding the spray tip and needle
valve assembly tight against the gauge,
read the needle valve lift on the indica-
tor. The lift should be 0.008" to 0.018".
If it exceeds 0.018", the tip assembly
must
be
replaced.
If
it
is
less
than
0.008", inspect for foreign material be-
t w e e n the needle valve and the tip seat.
4.
If
the
needle
valve
lift
is
within
limits, install a new needle valve spring
and recheck the valve opening pressure
and valve action. Low valve opening
pressure or poor atomization with a new
spring and seat indicates the spray tip
and needle valve assembly should be re-
placed.
5. Reassemble the injector as outlined
under "Assemble Injector" on page
11C-19
and
check
the
injector
output
w i t h calibrator J 22410.
NEEDLE VALVE TIP TEST WITH AUXIL-
IARY TESTER
1. Connect the pipe from auxiliary tester
J 22640 to the rear of the J 23010 tester
at the connection located near the bottom
of the tester (see Figure 11C-18 on page
Figure 11C-16. Adaptor and Tube on
Injector Tester
Fuel System and Governor
