Urrea UD226 Manual De Usuario Y Garantía página 41

• Red test probe to a good ground or the
negative (–) vehicle battery post.
• Black test probe to the wire that connects
to the breaker points.
Press the CYL (RANGE) button repeatedly
to select the required number of cylinders.
Start the engine and observe the reading.
Adjust trigger level pressing the ± TRIG
button repeatedly, if the reading is too
high or unstable.
Duty Cycle Measurements.
Duty Cycle is the percentage (%) of time
that voltage is positive compared to
negative: On compared to Off.
There are many signals on a vehicle
where you might be required to measure
duty cycle. Signals from Mixture Control
Solenoid of a feedback carburetor, signals
from Cam or Crank sensors and the
control signals for fuel injectors are good
examples.
This exercise shows how to measure duty
cycle on the signal for the mixture control
solenoid of a feedback carburetor using
the Meter.
RED (+)
BLACK (-)
JUMPER LEADS FROM
FEEDBACK SOLENOID
GOOD
GROUND
To measure duty cycle (%):
• Select the mS-Pulse range with the rotary
switch.
• Press the HOLD (Duty %) button until %
appears on the right side of the display.
Insert:
• Black lead in COM jack.
• Red lead in RPM, V, Ω jack.
Connect:
• Black test probe to a good ground at
the carburetor or the negative (–) vehicle
battery post.
• Red test probe to the solenoid signal.
Start the engine. A duty cycle of
approximately 50% should be read.
Adjust the trigger level pressing the ± TRIG
button repeatedly if reading is too high or
unstable.
Most car have the points of the solenoid
closed for a duty cycle between 50 ~ 70%.
Start the engine. A duty cycle of
approximately 50% should be read.
Adjust the trigger level pressing the ± TRIG
button repeatedly if reading is too high or
unstable.
Most car have the points of the solenoid
closed for a duty cycle between 50 ~ 70%.
Once the engine warms up and goes into
open loop, the duty cycle should fluctuate.
NOTE: Consult the car's service manual to
verify slope assigned to position for each
component.
Frequency (Automotive Hz)
Measurements
Frequency (Hz) is the number of times a
voltage pattern repeats positive compared
to negative, On Compared to Off, during
1 second of time. There are many sensors
E N G L I S H
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