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Plug
a BNC test lead into channel A on the Scope , place a large black
crocodile clip on the test lead with the black moulding (negative) and
an acupuncture probe onto the test lead with the red moulding
(positive). Plug a BNC test lead into channel B on the PicoScope ,
place an acupuncture probe onto the test lead with the red moulding
(positive). Place the large black crocodile clip onto the battery
negative and probe the sensor with the two acupuncture probes .
The
sensor will have three wires, two of these will display the alternating
current (ac) waveform as illustrated in the example on this page, the
other wire will be an earth.
Fig. 14.1.5
Figure 14.1.5
shows the two acupuncture probes back probing the camshaft sensor
multiplug at the connection within the recess of the cam cover on the
Vauxhall ECO TEC engine.
This type of sensor is used on some of the Vauxhall ECO TEC engines.
This Cylinder Identification (CID) sensor differs in operation from the
other inductive sensors by having an Alternating Current (AC) voltage
supply to the CID sensor.
The Electronic Control Module (ECM)
supplies a very high frequency at around 120 kHz to an exciter coil
that is located in close proximity to a rotating disc. The disc is
located at the end of the camshaft and has a section removed that when
'open' allows the frequency to excite the receptor (through mutual
inductance) and returns the signal to the ECM, indicating the position
of number 1 cylinder.
As
the frequency is so fast, the time scale should be set as fast as
possible so as the oscilloscope can capture the frequency. The CID
sensor is used as a reference for the ECM to determine the camshaft's
position, from which the correct timing for the sequential fuel
injection can be determined. |
