The EVA is supplied by SPX corporation and distributed through: OTC Tools, Rotunda Tools, and Kent-Moore Tools.
Select the type of EVA you are using. Typically General Motors Dealerships were the only ones to use the version 2.0 and 3.0 memory cartridges. EVA memory cartridge versions 1.0 and 3.0 will work with the Vibrate 5.1 software. The version 3.0 cartridge is a just a combination of the version 1.0 and 2.0 cartridges. Click here to read an EVA history and overview. The EVA2's "Auto Mode" can be inaccurate and can lead to misdiagnosis. Click here to see why.
Select the type of EVA you are using:
The following information is based upon my own memory, experience, and opinions. - John Kelly, President of Vibrate Software, Inc. -
As a vibration instructor and a user of the EVA since its introduction in 1991, I have had much experience with the EVA and its different memory cards. The EVA is a wonderful tool, which when used with Vibrate 5.1, takes the guesswork out of vibration diagnosis.
In 1991, Kent-Moore tools introduced the J-38792 (EVA) Electronic Vibration Analyzer. This tool uses an accelerometer to measure vibration frequency and amplitude levels. The top three amplitude levels with their corresponding frequencies are displayed on the EVA's screen. This tool also has the ability to assist a technician in system balancing a propshaft system. The EVA was not very user friendly. The data on the EVA's screen was not very useful; however, if the technician could perform some mathematical calculations involving tire size, axle gear ratio, and vehicle speed, he could attempt to match the frequency of a rotating component on the vehicle to a frequency displayed on the EVA's screen.
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This method of diagnosis was alright if the technician could perform the calculations correctly, but it was found that this method of using tire sizes and vehicle speed to calculate the rotational speed of vehicle components was flawed. The flaw was the result of tire tread wear, same size tires having different rolling radiuses, and the installation of oversize tires on the accuracy of the vehicle speedometer. There is also the problem of the inherit inaccuracies of an air-core electro-magnetic speedometer which can be inaccurate as much as 7 mph depending on the position of the needle verses the force gravity. If the speedometer is incorrect, the calculations will also be incorrect which can lead to misdiagnosis.
A more accurate method of calculating the rotational speeds of rotating vehicle components uses engine RPM and gear ratios. If the engine speed is known, the torque converter clutch is engaged, and the gear ratios of the transmission and axles are known, the rotational speed of the tires, propshaft, and etc. can be calculated regardless of tire size and vehicle speed. Vibrate 5.1 uses this calculation method.
Most automobile vibrations are caused by rotating components that are out-of-balance or out-of-round. Since the engine must be running for these components to begin rotating, the engine's crankshaft will be the point of reference for vibration diagnosis. Every rotating component will have a rotational velocity that is faster, slower, or the same as the engine's crankshaft. Determining the rotational velocity of each component in relation to the engine's crankshaft is the key to an accurate vibration diagnosis.
VIBRATE 5.0 calculates the rotational velocity of each component and graphically represents these velocities on a computer's screen and on a printed Vibration Worksheet. The printed vibration worksheet is for an automobile technician to use while test-driving a vibrating automobile. When the automobile's vibration is present, the technician records the vibration frequency and the engine RPM on the Vibration Worksheet. (The technician will need tools to measure vibration frequency and engine RPM.)
There is a point on the vibration worksheet where the vibration frequency reading and the engine RPM reading intersect. This point should be on, or very close to, a plotted line on the vibration worksheet. The plotted line indicates the specific component group causing the vibration. The technician can diagnose which component in the component group is causing the vibration by using the procedures outlined the Vibrate 5.1 Help file or in the vehicle manufacturer's service manual.
Automobile and truck technicians like this method of vibration diagnosis because the vibration worksheet is easy to understand and the technician is not required to perform any mathematical calculations.
In 1998, Kent-Moore tools introduced a "Smart EVA" memory cartridge in an attempt to automate the diagnostic process for technicians. The cartridge replaced the original memory cartridge in the EVA. Unfortunately for them, fortunately for Vibrate Software, the automated method they decided to use was still flawed because it was based on vehicle speed and tire size. Ford Motor Company turned down Kent-Moore Tools when offered the use of the "Smart Cartridge" and opted to use Vibrate 4.0. GM approved it's use, but soon discovered that it had its limitations, specifically when their vehicles had been modified with larger tires. In 1998, GM approved the use of Vibrate 4.0 as an alternate method of vibration diagnosis to the "Smart EVA". Vibrate 4.0 and (subsequent versions) was approved as an "available tool" by the GM tool committee and became a Kent-Moore tool, part number J-38792-VS.
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In 2000, Kent-Moore Tools introduced a "new" memory cartridge called the "EVA2". They included it with the old EVA with a faster processor looking new with a blue faceplate instead of a red one. The EVA2 memory cartridge was simply a combination of the original EVA cartridge and the Smart EVA cartridge. With this "new" cartridge, the technician can decide whether or not he will perform the calculations in the "normal mode", let Vibrate 5.1 perform the calculations in the "normal mode", or let the tool attempt the calculations in "auto mode". Kent-Moore and GM decided that this tool should be an essential tool for all GM dealerships. Prior to this, only GMC truck dealers had the EVA.
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The end result of all of this is: The "Smart Cartridge" or the EVA2's "Auto Mode" works just fine on original Equipment General Motors Vehicles up through the 2000 model year. Many new GM vehicles have powertrain configurations that the "Smart Cartridge" or the EVA2's "Auto Mode" do not support. If the vehicle is has been modified at all, including buying new tires, or if the vehicle is a non-GM product, the "Smart Cartridge" or the EVA2's "Auto Mode" are inaccurate and can lead to misdiagnosis. Click here to see why.
For all vehicles, the Vibrate 5.1 software combined with the EVA with the original cartridge or the EVA2 in "Normal Mode" will accurately assist a technician in diagnosing the source of the vibration, and in repairing the source of the vibration with feature rich context sensitive help.
EVA memory cartridge version 1.0 or version 3.0 will work with the Vibrate 5.1 software, not version 2.0.
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This page was last modified Saturday, August 13, 2011 11:59:39 AM
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