4000,S L4-1781cc 1.8L SOHC (MG) (1985)
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Hall Effect Sensor: Testing and Inspection
1.
Ensure that ignition coil is satisfactory.
2.
If vehicle is equipped with an idle stabilizer*, disconnect electrical plugs at idle stabilizer and connect them together.
NOTE: The DIS plugs are a common source of intermittent ignition problems. Before replacing ignition components replace the terminal
connectors and coat them with dielectric grease, then retest the system.
3.
Disconnect electrical connector at Hall control unit.
4.
Connect voltmeter positive lead to terminal 4 and negative lead to terminal 2 of harness plug.
5.
Turn ignition switch ON.
6.
If voltmeter does not read approximately battery voltage, check wiring and repair as necessary.
7.
Turn ignition switch OFF.
8.
Reconnect harness plug to the Hall control unit, and disconnect Hall generator connector at distributor.
10.
Connect voltmeter positive lead to terminal 15 and negative lead to terminal 1 of ignition coil.
11.
Turn ignition switch ON.
12.
If voltmeter does not read at least 2 volts for 1-2 seconds and then drop to zero, replace Hall control unit and ignition coil.
13.
With the ignition OFF, and the distributor connector disconnected, insert a metal pin into center terminal of Hall generator connector and switch
ignition ON.
14.
Briefly touch pin to suitable ground while observing meter, then switch ignition OFF.
15.
If voltage does not momentarily increase to at least 2 volts, check wiring and repair as necessary.
16.
If wiring is satisfactory, replace Hall control unit.
17.
Turn ignition switch OFF.
18.
Connect voltmeter to outer terminals of Hall generator connector.
19.
Turn ignition switch ON and ensure that there is at least 5 volts available.
If readings are within specifications but problem still exists, replace Hall control unit or check wiring between Hall generator connector and
Hall control unit.
20.
Reconnect the idle stabilizer.
* The DIS unit is located on top of the Hall control unit only on some cars with CIS injection.
