KNOVA KN 8056, Manual

Diagnosis of automotive Troubles

(3) Connect the red and black test lead probes in

     parallel to the two ends of the high-voltage

     damper and observe the reading. The normal

     resistance is generally in a range of 3 k

Ω

 to

     50 k

Ω

. In bending the lead, the reading should 

     remain unchanged.

The functions of a magnetic resistance sensor is

similar to those of a Hall sensor and the testing

methods of both sensors are also similar. Their

normal resistance is generally in a range of 150

Ω

 to

1 k

Ω

. Refer to the ranges of resistance in various

kinds of automotive manuals for the details.

3. Hall Switch/Sensor Testing

 (see figure 12)

5. RPMx10 Testing

 (see figure 14)

4. Magnetic Resistance Sensor

 (see figure 13)

figure 12

Red Signal Terminal

Hall Sensor

Iron

Plate

Hall Switch

Hall Switch

Ground

Ground

Black

Ground

Jumper

Ford Motor Fuel Dispenser

Chrysler Motor Fuel Dispenser

V+

V+

V+

Signal 

Terminal

Signal 

Terminal

When the tach and dwell are tested in the computer 

of the automobile, a Hall sensor is used. The Hall

sensor is normally used in the ignition system to

detect the position of the camshaft so that the

computer of the automobile can set the optimal time

for the ignition and the opening of the fuel injector.
(1) Move the Hall sensor out of the automobile and

     see the details of the operation in various kinds

     of automotive manuals.
(2) Connect the positive pole of the 9 V battery to

     the source end of the sensor and the negative

      pole to the ground end of the sensor by referring

     the details to the positions of the source and

     ground ends of the sensor in various kinds of

     automotive manuals.
(3) Set the rotary switch of the meter to 200W. 

      As prompted at the LCD connect terminal, insert

     the red test lead into the W terminal and

     the black one into the COM terminal.
(4) Connect the red and black test lead probes in

      parallel to the signal connect terminal and ground

     end of the sensor and the Meter should display

     a small ohm value.
(5) When a metal plate (blade, steel tape, etc.) is

     inserted into a concave magnetic pole of the

     sensor, the display of the meter will be enlarged

     or overloaded; if the metal plate is moved away,

     the display will become smaller, which proves

     that the sensor is satisfactory.

(1) Set the rotary switch to RPMx10 and select the

     number of cylinders in the automobile to be tested.
(2) As prompted at the LCD connect terminal, insert

     the red test lead into the      terminal and the

     black one into the COM terminal.
(3) Connect the black test lead probe to the ground 

      (i.e. ground strap connection) of the automobile

      and the red one to: the appropriate testing test

      terminal of the computer of the automobile if the

      automobile is in a DIS type (Refer to the

      servicing handbooks of various kinds of

      automotive manuals for the detailed position);

      or the negative pole of the ignition coil if the

      automobile is equipped with a distributor board

      (Refer to the servicing handbooks of various

      kinds of automotive manuals for the detailed

      position).
(4) The normal starting rotation speed of an engine

     is about 50 RPM to 275 RPM. Refer the detailed

     position to the servicing handbooks of various

     kinds of automotive manuals because this value

     relates to the current temperature, engine size,

     battery size, etc.

6. Fuel System Testing

It is necessary to add more accurate engine fuel

control to a low injection automobile. Since 1980,

the automotive manufacturing industry has used

electronically-controlled carburetor and fue

injection so as to achieve lower fuel injection.
(1) GM (General Motor): Testing the dwell of the

     C-3 mixed-control solenoid: Place the solenoid

     in a cylinder, monitoring the ratio between the

     air and the fuel, which should generally be 14.7

     to 1 between the air and the fuel so as to

     reduce  the injection of surplus fuel. The

     testing is used to see if the solenoid is installed

     right in the position and the dwell of the meter

     can also indirectly used for the testing.

figure 13

Magnet

Black

Red

Magnetic Resistance Sensor

Magnetic

Resistance 

Distributor

figure 14

Red

Black

Ground

Ignition

Coil

          • The displayed value of the meter becomes

the actual tach reading only after it is multiplied by

10.

WARNING

10