Econoline E350 1 Ton V8-5.4L Prop SOHC VIN Z (1998)
speed-related.
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The Neutral Run-up Test is used as a follow-up test to the Downshift Speed Test when the concern occurs at idle.
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The Engine Load Test helps to identify vibration/noise sensitive to engine load or torque. It also helps to reproduce engine speed-related concerns
that cannot be duplicated when carrying out the Neutral Run-up Test or the Neutral Coast Down Test.
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The Engine Accessory Test helps to locate faulty belts and accessories that cause engine speed-related concerns.
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The Vehicle Cold Soak Procedure helps to identify concerns occurring during initial start-up and when an extended time lapse occurs between
vehicle usage.
Slow Acceleration Test
To carry out this test, proceed as follows:
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Slowly accelerate to the speed where the reported concern occurs. Note the vehicle speed, the engine rpm and, if possible, determine the vibration
frequency.
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Attempt to identify from what part of the vehicle the concern is coming.
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Attempt to identify the source of the concern.
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Proceed as necessary.
Heavy Acceleration Test
To carry out this test, proceed as follows:
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Accelerate hard from 0-64 km/h (0-40 mph).
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Decelerate in a lower gear.
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The concern is torque related if duplicated while carrying out this test.
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Proceed as necessary.
Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
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Drive at a higher rate of speed than where the concern occurred when carrying out the Slow Acceleration Test.
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Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
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The concern is vehicle speed-related if duplicated while carrying out this test. This eliminates the engine and the torque converter as sources.
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If the concern was not duplicated while carrying out this test, carry out the Downshift Speed Test to verify if the concern is engine speed related.
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Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
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Shift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
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Drive at the engine rpm where the concern occurs.
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The concern is engine speed related if duplicated while carrying out this test. This eliminates the tires, wheels, brakes and the suspension components
as sources.
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If necessary, repeat this test using other gears and NEUTRAL to verify the results.
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Proceed as necessary.
