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 109 of 1563

TM 9-2815-220-24

ENGINE LOW IDLE ABNORMAL OPERATION

0009 00

THIS WORK PACKAGE COVERS:

Troubleshooting Table and Diagnostic Tests

INITIAL SETUP:

Tools:

General mechanic's tool kit (item 121, WP 0176)

Personnel Required

Track Vehicle Repairer (2) 63H10

Equipment Conditions:

Engine installed in vehicle or ground hop.

MALFUNCTION 1:

Low idle speed, below 650 rpm.

PROBABLE CAUSE

CORRECTIVE ACTION

a. Insufficient warm-up.

Applies in cold

weather.

(1) Extend warm-up period.

Increase warm-up

speed to 1000 - 1200 rpm.

b. Improper idle adjustment.

(1) Adjust idle speed (WP 0043, Throttle

Adjustments).

c. One bank not firing.

(1) Increase warm-up speed to 1000 - 1200

rpm.

If bank still does not fire, check fuel-

injection pump operation as follows:

PROCEDURE

OBSERVATION

ANALYSIS

Remove one engine cover on

each side of engine for access to

fuel injector nozzle tube fittings.

Crank engine with fuel switch

"ON" or start engine and operate

at idle speed.

High-pressure fuel spray

pulsations at nozzle fitting.

Fuel injection pump action

is normal.

Loosen fuel injector tube fitting

at nozzle end sufficiently to

allow fuel leakage (one nozzle

on each side of the engine.

No fuel spray pulsations

noted at nozzle fitting.

Fuel injection pump

deficiency.

Replace fuel-

injection pump (WP 0115,

Fuel Injection Pump

Assembly Replacement).

Bench Test

Install nozzle and holder

assembly on tester.

Perform nozzle test (WP 0098,

Fuel Injector Nozzle and Holder

Repair).

Spray pattern and nozzle

leakage test requirements.

If spray pattern is not

acceptable and leakage is

noted, nozzle is defective.

WP 0009 00-1