Figure 11C-18. Injector Needle Tester with Auxiliary Tester J 22640
2. Assemble cleaned injector parts, in-
functioning in the engine. Note the
cluding the check valve cage, spring,
pressure at which the test oil delivery
spring cage and spray tip assembly, on
occurs. Test oil delivery should occur
the
auxiliary
tester
J
22640
(see
between 2200 and 3200 psi (15,158 and
22,048 kPa). The beginning and ending
of delivery should be sharp and the test
3. Carefully pilot the injector nut over
o i l should be a finely atomized spray.
the spray tip and valve parts and thread
it on the auxiliary tester.
If the valve opening pressure is below
2200 psi (15,158 kPa) and/or atomization
4. Tighten the injector nut.
is poor, the cause is usually a weak
valve spring or poor needle valve seat.
5. Open the valve on the auxiliary tester
If the valve opening pressure is within
and place lever 4 in the up (horizontal)
position.
2200-3200 psi (15,158-22,048 kPa), pro-
ceed to check for spray tip leakage as
6. Install the shield on the auxiliary tes-
follows:
ter and operate pump lever 1 until the
A. Actuate the pump lever several times
needle valve has opened several times to
and hold the pressure at 1500 psi
purge the air from the system.
(10,335 kPa) for 15 seconds.
7. Operate pump lever 1 rapidly with
B. Inspect the spray tip for leakage.
smooth even strokes (40 strokes per mi-
There should be no fuel droplets, al-
nute) simulating the action of the tip