4TNV98 & 4TNE98 Diesel Engine Section 4. Fuel System167See the parts catalog for available shims.CAUTIONEach pressure adjusting shim removed oradded changes the pressure threshold byapproximately 275 psi (1.9 MPa, 19 kgf / cm²).Adding adjusting shims increases the thresholdpressure. Removing adjusting shims reducesthe pressure threshold.1. Disassemble the fuel injector assembly. SeeDisassembly and Inspection of Fuel Injectors onpage 165.2. Remove or add adjusting shims as needed.3. Reassemble the fuel injector assembly. SeeReassembly of Fuel Injectors on page 166.4. Retest the fuel injector. See Testing of FuelInjectors on page 164. If the injector cannot beadjusted to the appropriate pressure, discard thefuel injector.Reassembly of Fuel Injectors1. Secure the injector in a soft-jawed vise with thenozzle end up.2. Reinstall the shims, nozzle spring, nozzle springseat, valve stop spacer, nozzle valve, and nozzlebody.3. Reinstall the nozzle case nut. Tighten it tospecification. See Special Torque Chart on page143.Installation of the Fuel Injectors4-Valve Cylinder Head1. Reinsert a new nozzle seat (Figure 7-57, (6))and nozzle protector (Figure 7-57, (5)) in thecylinder head for each injector.2. Reinstall a O-ring on to each injector body.3. Reinsert each fuel injector (Figure 7-57, (4)) intothe cylinder head.4. Reinstall the fuel injector retainers (Figure 7-57,(3)) and torque the retaining bolts (Figure 7-57,(2)) to specification.5. Reinstall the fuel injector return line assemblyusing new gaskets on each side of the injectorline screws.6. Reinstall the fuel high-pressure fuel lines to eachinjector and tighten the nuts using a “line” or“flare nut” wrench.Figure 7-577. Prime the fuel system. See Priming the FuelSystem on page 15.8. Operate the engine and check for fuel andcoolant leaks.
