2-4. ENGINE TROUBLESHOOTING (CONT)
TEST OR INSPECTION
4. ENGINE MISFIRES (Cont).
Step 12. Remove five capscrews securing gear cover and gasket to timing gear
Check fuel injection pump drive gear to idler gear backlash using
Backlash should be 0.012 inch.
a. If backlash exceeds 0.012 inch, replace fuel injection pump
drive gear (page 3-136).
Recheck backlash. If backlash still exceeds 0.012 inch, replace
idler gear (page 4-54).
Perform fuel injection pump governor adjustments (page 3-14).
If backlash does not exceed 0.012 inch, go to Malfunction 1,
Remove cylinder head assemblies (page 3-45).
Remove valve locks, valve retainers, and springs (page 3-74).
Check for bent valves or worn or broken valve spring (page 3-76).
If a valve is
If valves and
bent or a valve spring broken, replace (page
valve springs are okay, check for incorrectly in-
guide (page 4-12).
If valve guides are okay, check for a bent connecting rod. Do
this by cranking engine until piston is at top dead center.
Measure height of piston between top of piston to top of cylin-
der sleeve. Repeat for remaining pistons. A difference of 0.020
inch will indicate a bent connecting rod. Notify general support
maintenance to replace bent connecting rods (page 4-42).