TM-9-2320-361-20
2-1/2-TON, 6x6, M44A2 SERIES TRUCKS (MULTIFUEL)
TECHNICAL MANUAL; UNIT MAINTENANCE
OCTOBER 1991
TM-9-2320-361-20 - Page 243 of 1207
TM 9-2320-361-20
2-21. VEHICLE TESTING (Contd)
c. Control Tests.
These tests are used to change (or control) the way a vehicle test is displayed, or the
way it is run. There are five (5) control tests:
01 Interleave (displays RPM with next test).
02 Display minimum value for next test.
03 Display maximum value for next test.
04 Display peak-to-peak value for next test.
05 Initiate full power simulation.
Control tests 01, 02, 03, and 04 specify action to be taken by the next test only.
A subsequent test will reset the control.
(1) Interleave (Test 01).
This test alternately measures engine speed and a second parameter such as
fuel pressure or alternator voltage. To initiate interleave, dial 01 into TEST SELECT switches and press
and release TEST button. The prompting message PASS will signal the technician to dial in second test
number and again press and release TEST button.
(2) Minimum Value (Test 02).
This test displays minimum value measured during a test. To initiate a
minimum value display, dial 02 into TEST SELECT switches and press and release TEST button. The
prompting message PASS will signal technician to dial in desired test number and again press and release
TEST button. The minimum value is displayed and updated whenever a lower minimum value is measured.
Entering 02 and test number again will reset process and a new minimum value will be displayed.
(3) Maximum Value (Test 03).
This test displays maximum value measured during a test. To initiate a
maximum value display, dial 03 into TEST SELECT switches and press and release TEST button. The
prompting message PASS will signal technician to dial in desired test number and again press and release
TEST button. The maximum value is displayed and updated whenever a higher maximum value is
measured. Entering 03 and test number again will reset process and new maximum value will be displayed.
(4) Peak-to-Peak Value (Test 04).
This test displays peak-to-peak value of dwell (test 16), alt/gen
output volts (test 82), 45-volts DC (test 89), 1500 amps DC (test 90), and battery volts (test 67). Electrical
peak-to-peak is for measuring dwell variation. To start peak-to-peak measurement, dial 04 into TEST
SELECT switches and press TEST button. The prompting message PASS will signal operator to dial in one
of five test numbers (16, 82, 89, 90, 67) and again press TEST button.
(5) Full Power Simulation (Test 05).
This test lets you test SI engines under full power operating
conditions. Test 05 differs from the previous four control tests in several ways. First, it must be preceded by
a number-of-cylinders entry (test 58) or VID entry (test 60). After number of cylinders or VID has been
entered, and engine is warm and idling, 05 is dialed into TEST SELECT switches, and TEST button is
pressed. The prompting message SIP will signal operator to press accelerator to floor. The VTM will monitor
engine speed during acceleration, and at approximately 3500 rpm, VTM will begin full power simulation.
Simulation will continue until operator releases accelerator. PASS message is displayed when simulation
starts. A measurement can now be made during power simulation by dialing desired test number and
pressing TEST button. New test and control functions can be selected until accelerator is released. The 05
control feature provides a more accurate indication of engine performance than does testing under unloaded
conditions.
2-158
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