Econoline E350 1 Ton V8-5.4L Prop SOHC VIN Z (1998)
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Shift the transmission into DRIVE, and increase and decrease the engine rpm between an idle to approximately 2000 rpm. Note the engine rpm and,
if possible, determine the vibration frequency.
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Repeat the test in REVERSE.
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If the vibration/noise is duplicated when carrying out this test, inspect the engine and transmission or transaxle mounts.
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If the concern is definitely engine speed-related, carry out the Engine Accessory Test to narrow down the source.
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Proceed as necessary.
Engine Accessory Test
To carry out this test, proceed as follows:
WARNING:
Block the front and rear wheels, and apply the parking brake and the service brake, or injury to personnel can result.
CAUTION:
Limit engine running time to one minute or less with belts removed or serious engine damage will result.
Note:
A serpentine drive belt decreases the usefulness of this test. In these cases. use a vibration analyzer, such as the EVA, to pinpoint accessory
vibrations. An electronic listening device. such as an EngineEAR, will also help to identify noises from specific accessories.
Remove the accessory drive belts.
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Increase the engine mm to where the concern occurs.
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If the vibration/noise is duplicated when carrying out this test. the belts and accessories are not sources.
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If the vibration/noise was not duplicated when carrying out this test, install each accessory belt, one at a time, to locate the source.
Vehicle Cold Soak Procedure
To carry out this procedure, proceed as follows:
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Test preparations include matching customer conditions (if known). If not known, document the test conditions: gear selection and engine rpm.
Monitor the vibration/noise duration with a watch for up to three minutes.
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Park the vehicle where testing will occur. The vehicle must remain at or below the concern temperature (if known) for 6-~ hours.
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Before starting the engine, conduct a visual inspection under the hood.
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Turn the key on. but do not start the engine. Listen for the fuel pump. anti-lock brake system (ABS) and air suspension system noises.
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Start the engine.
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CAUTION:
Never probe moving parts.
Isolate the vibration/noise by carefully listening. Move around the vehicle while listening to find the general location of the vibration/noise. Then, search
for a more precise location by using a stethoscope or EngineEAR.
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Refer to Idle Noise/Vibration in the Symptom Chart to assist with the diagnosis.
6. Check OASIS/TSBs/Repair History
After verifying the customer concern, check for OASIS reports, TSBs and the vehicle repair history for related concerns. If information relating to a
diagnosis/repair is found, carry out the procedure(s) specified in that information.
If no information is available from these sources, carry out the vehicle preliminary inspection to eliminate any obvious faults.
7. Diagnostic Procedure
Qualifying the concern by the particular sensation present can help narrow down the concern. Always use the "symptom" to "system" to "component" to
"cause" diagnosis technique. This diagnostic method divides the problem into related areas to correct the customer concern.
