DETROIT DIESEL 53
2.1.1 Fuel lnjector
An injector that passes all of the tests outlined below
connectors from entry of dirt or foreign
may be considered to be satisfactory for service
material.
without disassembly, except for the visual check of the
plunger.
3. Crank the engine to bring the outer ends of the
push rods of the injector and valve rocker arms in line
However, an injector that fails to pass one or more of
horizontally.
the tests is unsatisfactory. Perform all of the tests
before disassembling an injector to correct any one
4. Remove the two rocker shaft bracket bolts and
condition.
swing the rocker arms away from the injector and
valves (Fig. 7).
Identify each injector and record the pressure drop
and fuel output as indicated by the following tests:
5. Remove the injector clamp bolt, special washer and
clamp.
6. Loosen the inner and outer adjusting screws on the
INJECTOR CONTROL RACK AND
injector rack control lever and slide the lever away
PLUNGER MOVEMENT TEST
from the injector.
Place the injector in the injector fixture and rack
7. Lift the injector from its seat in the cylinder head
freeness tester J 22396. Refer to. Fig. 8 and place the
(Fig. 7).
handle on top of the injector follower.
8. Cover the injector hole in the cylinder head to keep
If necessary, adjust the contact screw in the handle to
foreign material out.
ensure the contact screw is at the center of the follower
when the follower spring is compressed.
9. Clean the exterior of the injector with clean fuel oil
and dry it with compressed air.
With the injector control rack held in the no-fuel
position, push the handle down and depress the
follower to the bottom of its stroke. Then very slowly
Test Injector
release the pressure on the handle while moving the
control rack up and down as shown in Fig. 8 until the
follower reaches the top of its travel. If the rack does
If inspection does not reveal any external damage,
then perform a series of tests to determine the
condition of the injector to avoid unnecessary
overhauling.
Fig. 13. Installing Injector Valve Parts on
Fig. 12. Unusable Injector Plungers
Auxiliary Tester J 22640
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