TM 5-3825-229-14&P
6-14. FUEL INJECTORS (cont)
b.
Testing (cont).
(b)
Check spray pattern as diesel fuel is forced from the nozzle.
(c)
As the needle lifts off the seat a small amount of fuel-enters the combustion chamber as "prespray." As the
fuel pressure continues to rise, the needle fully opens and the main spray of fuel is injected into
combustion chamber.
(d)
If spray patterns are not as shown, repair fuel injector.
(6) Check nozzle for leakage.
(a)
With pressure valve still open, depress hand lever until the pressure is 150 psi (1,034 kPa).
(b) If the pressure drops within 10 seconds, the nozzle is leaking. Check to see if diesel fuel is falling in drops
from injector.
(c) If drop forms the nozzle is leaking and must be cleaned and repaired.
c.
Disassembly.
WARNING
Wear protective goggles when using the cleaning solvent. Avoid contact with the eyes. If contact occurs, flush eyes with
cold water for 5 minutes and seek immediate medical attention. Dry cleaning solvent (PD-680) is both toxic and
flammable. Avoid prolonged breathing of vapors. Avoid skin contact. Use only in a well-ventilated area. Keep away from
open flame. Flash point of solvent is 138°F (59C).
(1) Clean outside of injector assembly with cleaning solvent (PD-680) and dry thoroughly.
(2) Clean carbon residue from the nozzle tip and nozzle tip nut with astiff wire brush.
(3) Clamp upper nozzle body (1) in a vise with copper jaw covers.
(4) Loosen the nozzle tip nut (2) from upper body.
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