User Manual

200 TROUBLESHOOTING
Page 9-5
ENGINE WILL NOT ACHIEVE NO-LOAD GOVERNED RPM
200773a
EXCESSIVE ENGINE VIBRATION
200774a
EXCESSIVE BLACK OR GRAY SMOKE
200775a
Possible Cause Correction
1. Air in fuel system. 1. Check system for air leaks and correct as required. Air will
generally enter the fuel system on the suction side of the fuel
transfer pump.
2. Accelerator linkage loose or out of adjustment. 2. Check linkage. Make necessary adjustments.
3. Restricted fuel lines or stuck overflow valve. 3. Check flow in fuel lines. Check overflow valve for defects, improper
setting, sticking, or defective spring.
4. High idle adjustment set too high. 4. Check high idle adjustments. Adjust as required.
5. Chassis equipped with MACK Maxi-Miser: Air
leaks in the air supply line or defective control
valve.
5. Leaks in the air supply line to the transmission, or from the
transmission to the fuel injection pump governor, will restrict
maximum engine rpm in all gears. Check all lines and connections
for leaks and repair as required. Replace control valve if
necessary.
6. Fuel injection pump calibration incorrect. 6. Remove injection pump and nozzle assemblies from the engine.
Send the pump to an authorized MACK Fuel Injection System
Repair facility for repair and recalibration. Then reinstall the pump.
7. Internal fuel pump governor wear. 7. Remove the injection pump. Send the pump to an authorized MACK
Fuel Injection System Repair facility for repair and recalibration.
Then reinstall the pump.
Possible Cause Correction
1. Loose vibration damper hub nut bolt. 1. Check condition of mounting. Make necessary repairs and
retorque.
2. Defective or damaged vibration damper. 2. Replace damper if it is verified as damaged or defective.
3. Fan blade not balanced. 3. Loosen or remove fan belts. Run the engine for a short period of
time at the rpm where the vibration was most noticeable. If the
vibration disappears, replace the fan assembly.
4. Engine supports loose, worn or defective. 4. Tighten all mounting bolts, or replace components as required.
5. Engine misfiring or running rough. 5. Check items listed in ENGINE MISFIRES in this section.
Possible Cause Correction
1. Insufficient air for combustion. 1. Check air cleaner for restrictions. Check inlet manifold pressure,
and inspect the turbocharger for proper operation. Repair
or replace as required.
2. Excessive exhaust back pressure. 2. Check for faulty exhaust piping or restrictions in the muffler. Repair
or replace as required.
3. Improper grade of fuel. 3. Drain fuel from tank(s). Replace fuel filters and fill tank(s) with
MACK-specified diesel fuel.
4. Faulty fuel injection nozzle. 4. Isolate faulty nozzle and replace. Refer to item 7 in ENGINE
MISFIRES in this section.
5. Improper injection pump-to-engine timing. 5. Check timing and adjust as required.
5-101.bk Page 5 Friday, March 17, 2006 11:05 AM