IMS 3638 Manual Del Usario página 34

30 Exhaust Noise Inspector Type 3638 – User Manual
Measurement Procedure
At measurement startup, it may take two test operators – one to operate the vehicle and another
to monitor the tachometer's display. Once it is confirmed that the measurement distance is
correct (an 'R' flashes on the tachometer's display), the second operator must leave the test area
to ensure accurate sound level measurements.
Warning: Never place the tachometer right next to the vehicle engine's moving parts (fan,
alternator, fan belt, etc.). Ensure that the instrument is stably balanced inside a running engine.
1) Using the supplied cable, connect the tachometer to the controller socket (as shown below)
placed at the top-right corner of the controller unit.
2) Place the tachometer 10 to 40 cm from the vehicle's spark plug leads with the tachometer
facing the leads. The tachometer measures all ignition pulses emitted; therefore, it must be
directly in sight of all the plug leads, or the common lead from the coil to the distributors.
The angle of the tachometer is of no importance.
3) Switch on the tachometer by positioning the instrument's dial on a number between 1 and
8. All instrument symbols will appear in the display for approximately 0.5 s when it is
initially switched on.
4) The tachometer's dial should be positioned on a number corresponding to the type of
engine to be tested. See the table below to position the dial correctly:
Position of
Dial
OFF
Type of
Engine
–
1 4 stroke
4 stroke
2
2 stroke
3 4 stroke
4 stroke
4
2 stroke
5 4 stroke
4 stroke
6
2 stroke
7 4 stroke
8 4 stroke
Number of
Function
Cylinders
– OFF
1 1 pulse/2 revs
2
1 pulse/1 rev
1
3 3 pulses/2 revs
4
2 pulses/ 1 rev
2
5 5 pulses/2 revs
6
3 pulses/1 rev
3
8 4 pulses/1 rev
12 6 pulses/1 rev