TM 5-3805-261-34
ENGINE TROUBLESHOOTING AND MAINTENANCE PROCEDURES. (cont)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
b.
ENGINE MISFIRES OR RUNS ROUGHLY.
Step 1.
Check the fuel pressure at the fuel injection pump housing. Fuel pressure at high idle should be 15 psi.
If the fuel pressure is below 15 psi--replace fuel filter element.
Step 2.
Check the fuel bypass and check valves in the fuel transfer pump.
If the bypass or check valves are damaged or defective--replace. Refer to paragraph 3-29.
Step 3.
Check fuel injection valves and pumps. Run the engine at an RPM that causes rough running. Loosen
a fuel line nut on the injection valve of each cylinder.
If the loosening of a fuel line nut does not make a difference--replace injection valve. Refer to paragraph 3-
25.
Step 4.
Check the fuel system timing.
If the fuel system is not timed correctly for the engine--adjust. Refer to paragraph 3-27.
Step 5.
Check the valve clearance.
If the valve clearance is not correct--service or replace. Refer to paragraph 3-13.
Step 6.
Check the push rods.
If a push rod is bent or broken--replace. Refer to paragraph 3-11.
Step 7.
Check for worn valves or valve seats.
If the valves or valve seats are worn--cylinder head should be reconditioned. Contact General Support.
Step 8.
Check the balancer shafts.
If balancer shafts are out of alignment -- replace.
Refer to paragraph 13-6.
3-4
