1.3 Parameters of technical features
This sensor is designed to be mounted on the plane of auto engine intake manifold. The
pressure connecting pipe together with the temperature sensor protrudes inside the intake manifold
and an O gasket is used to enable atmosphere-proof.
If it is mounted on an auto through an appropriate method (picks up pressure from the intake
manifold and the pressure connecting pipe tilts down etc.), it can be ensured that no condensed water
will be formed on the pressure-sensitive element.
Drilling and fixing on the intake manifold must be carried out according to the supply drawing
so as to ensure a long seal and a good tolerance to fretting by agent.
The reliable contact of electric connection of a joint will mainly be affected by the joints of
components and parts, and it is also in relation to the material quality and dimensional precision of
the joint fitted with it on the harness.
1.4 Failure effects and judgment method
l Failure effects: spark extinction and poor idling etc.
l General Failure Reason:
1. Abnormal high voltage or inverse strong current occur during working;
2. The vacuum element is damaged during maintenance.
l Maintenance precautions: during maintenance, impinge using high pressure gas toward the
vacuum element is prohibited; when replacing the sensor after a failure is found, remember to
check if output voltage and current of the generator is normal.
l Simple measurement method:
1.4.1 Temperature sensor:
With the joint removed, turn the digital multimeter to Ohm shift, and then connect the two
meter pens respectively to 1# and 2# pins of the sensor; At 20, the rated resistance should be 2.5 ℃
kΩ±5%, and the other corresponding resistances can be measured out from the characteristic curve
in above chart. Analogue method can also be used when measuring, i.e., use an electric drier to blow
the sensor (be careful not to be too close to the sensor), and then observe the change of the sensor
resistance. At this point, the sensor resistance should fall.
1.4.2 Pressure sensor:
With the joint connected, turn the digital multimeter to DC Voltage shift, and then connect the
black pen to ground while the red pen respectively to 3# and 4# pins. Under idle speed state, 3# pin
should have a 5V reference voltage while the voltage on 4# pin should be around 1.3V (the actual
value depends on the model); Under no load state, when opening the throttle slowly, the voltage on
4# pin may change little; when opening the throttle rapidly, the voltage on 4# pin may reach around
4V instantly (the actual value depends on the model) and then fall to around 1.5V (the actual value
depends on the model).
