TM-9-2815-225-34-P

ENGINE, DIESEL: 6 CYLINDER IN-LINE TURBOCHARGED, CUMMINS MODEL NTC-400

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST

JULY 2005

TM-9-2815-225-34-P - Page 400 of 736

TM 9-2815-225-34&P

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FUEL PUMP TESTING AND CALIBRATION (Contd)

CHECKING AND ADJUSTING THROTTLE LEAKAGE

NOTE

If throttle leakage is adjusted correctly on fuel pump test

stand, fuel pump will not need to be adjusted on engine.

Vehicle throttle linkage must be adjusted so that threaded stud

of throttle leakage adjusting screw (rear screw) just contacts

stop in pump throttle.

The purpose of the throttle leakage is to keep the fuel lines and

injector drilling full of fuel during closed throttle operation.

The correct throttle leakage will help acceleration when the

throttle is opened after going down a grade. Throttle leakage

will also prevent stalling when it slows down to the idle speed.

Too much leakage will cause slow deceleration.

1.

Bring engine (1) to full throttle and allow engine (1) to run at maximum no-load speed.

2.

Release or move throttle quickly and start a suitable timer or stopwatch at the same time.

3.

Stop timer when 1000 rpm is reached and check deceleration time. Repeat this check several

times.

4.

Increase leakage as engine (1) begins to stall (idle governor does catch engine after deceleration

from high idle) by turning in threaded stud (3).

5.

Recheck engine (1) deceleration until time is increased 1-2 seconds.

6.

Lock threaded stud (3) with jamnut (2).

7.

Recheck idle speed and readjust as necessary.

8.

Bring engine to 1000 rpm.