On-Screen Diagnostics

On-Screen diagnostics is a feature that causes the mouse arrow to change to a cross hair while it is on the vibration graph. The information bar at the bottom left of the screen will display the cross-hair coordinates in vibration frequency and engine RPM. Click the left mouse button on the screen to mark up to three different coordinates on the graph, click the right mouse button to clear the coordinates

EXAMPLE: The vehicle used in this example is a 4WD Truck with a 3.73:1 axle gear ratio and a transmission fourth gear ratio of 0.70:1. This vehicle has a mild vibration at freeway speeds. Enter your own vehicle's information and follow these same steps to diagnose the source of the vibration.

The following readings were taken while road testing the truck on the freeway at a steady speed.

The Engine tachometer equals 2000 RPM

The EVA’s primary vibration frequency (the top row of numbers) equals 1560 RPM while the vibration was occurring.

or if using the MTS 4000/4100, the primary vibration frequency (the top row of numbers) equals 25 Hz while the vibration was occurring.

Mark the engine RPM and the Vibration RPM or Hz on the worksheet as shown below. The engine RPM and vibration RPM lines intersect on the T2 line. T2 represents a second order tire speed related vibration.

With EVA

With MTS 4000/4100

After the Road Test

After the road test, the technician uses the readings obtained on the road test to line up the mouse cross hair.

The mouse cross hair intersects at the T2 line. T2 represents a second order tire speed related vibration.

Move the mouse to the T2 button on the right side of the screen and press it.

A box appears and tells you the common causes of T2 vibrations. Press the Help button to open the context sensitive help file.

Click here to access the same help file shown above. Follow the diagnostic directions to isolate the source of the vibration.

This page was last modified Thursday, March 05, 2009 09:02:24 PM