TM-9-2815-220-24

AVDS-1790 2CA, 2DA and 2DR Air-Cooled 12-Cylinder Diesel Engines

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL FOR AVDS-1790 2CA, 2DA and 2DR Air-Cooled 12-Cylinder Diesel Engines

TM-9-2815-220-24 - Page 110 of 1563

TM 9-2815-220-24

ENGINE LOW IDLE ABNORMAL OPERATION

0009 00

MALFUNCTION 1:

(Continued)

Low idle speed, below 650 rpm.

PROBABLE CAUSE

CORRECTIVE ACTION

c. (Continued)

One bank not firing.

(2) Check inlet filter (watchdog) on fuel

injection pump (TM9-2910-212-34 & P).

MALFUNCTION 2:

Low-idle speed erratic (unsteady or surge).

PROBABLE CAUSE

CORRECTIVE ACTION

a. Idle speed too low.

(1) Adjust idle speed (WP 0043, Throttle

Adjustments).

b. Accelerator or throttle linkage loose, worn,

or cross-shaft shock spring defective.

(1) Inspect linkage (WP 0122, Throttle Control

and Manual Fuel Shutoff Replace/Repair).

(WP 0123 for 2DR)

c. One or more cylinders partially firing.

(Water or air in fuel system).

(1) Refer to WP 0020, Fuel System Abnormal

Conditions.

d. Injector nozzles defective.

(1) Remove and check nozzles (WP 0114, Fuel

Injector Nozzle Replace/Repair).

e. Fuel-injection pump governor defective.

(1) Replace defective fuel-injection pump

(WP 0115, Fuel Injection Pump Assembly

Replacement).

f.

Fuel injection-pump improperly timed.

(1) Check timing (WP 0036, Injection Pump

Timing).

MALFUNCTION 3:

Misfires at idle (usually accompanied by white exhaust smoke, oily or heavy carbon deposits

on exhaust grilles).

PROBABLE CAUSE

CORRECTIVE ACTION

a. Engine operating at idle for extended period

during cold weather.

(1) Increase engine idle speed to 1000 - 1200

rpm.

END OF WORK PACKAGE

WP 0009 00-2