2.1.1
FUEL Injector
DETROIT DIESEL 53
connectors from entry of dirt or foreign material.
3. Crank the engine to bring the outer ends of the push rods of the injector and valve rocker arms in line
horizontally.
4. Remove the two rocker shaft bracket bolts and swing the rocker arms away from the injector and valves (Fig. 7).
5. Remove the injector clamp bolt, special washer and
clamp.
6. Loosen the inner and outer adjusting screws-on the injector rack control lever and slide the lever away from the
injector.
7. Lift the injector from its seat in the cylinder head (Fig. 7).
8. Cover the injector hole in the cylinder head to keep foreign material out.
9. Clean the exterior of the injector with clean fuel oil and dry it with compressed air.
Test Injector
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.
An injector that passes all of the tests outlined below may be considered to be satisfactory for service without
disassembly, except for the visual check of the plunger.
However, an injector that fails to pass one or more of the tests is unsatisfactory.
Perform all of the tests before
disassembling an injector to correct any one condition.
Identify each injector and record the pressure drop and fuel output as indicated by the following tests:
INJECTOR CONTROL RACK AND PLUNGER MOVEMENT TEST
Place the injector in the injector fixture and rack freeness tester J 22396. Refer to Fig. 8 and place the handle on top of
the injector follower.
If necessary, adjust the contact screw in the handle to ensure the contact screw is at the center of the follower when the
follower spring is compressed.
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 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
Fig. 12 Unusable Injector Plungers
Fig. 13 Installing Injector Valve Parts
on Auxiliary Tester J 22640
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