Troubleshooting Electrical System

Troubleshooting Electrical System





CONNECT AN OHMMETER TO TERMINAL: # 2 and # 4

Specifications:
With oxygen sensor disconnected Infinite ohms

Checks:
Shielding of oxygen sensor wire.

Possible cause of Problem:
Shorted wire between terminal # 2 and # 4.

CONNECT AN OHMMETER TO TERMINAL: # 2 and Ground

Specifications
With wire to oxygen sensor grounded 0 ohms

Checks:
Wire from control unit to oxygen sensor.

Possible cause of Problem:
Broken wire from terminal # 2 to oxygen sensor.





CONNECT AN OHMMETER TO TERMINAL: # 5 and Ground

Specifications:
0 ohms

Checks:
Ground circuit.

Possible cause of Problem:
Loose or corroded ground connection.





CONNECT AN OHMMETER TO TERMINAL: # 7 and Ground

4 Cylinder Engine (1979 5 cyl.)

Specifications:
Below 68° F 0 ohms
Above 77° F infinite ohms

Checks:
Temperature switch for cold enrichment.

Possible cause of Problem:
Defective temperature switch, loose or corroded ground.

5 Cylinder Engine

Specifications:
Below 86° F 0 ohms
Engine above 104° F Infinite ohms

Checks:
Temperature switch for cold enrichment.

Possible cause of Problem:
Defective temperature switch, loose or corroded ground.

Specifications:
Accelerator pedal pressed to floor,
Temperature switch disconnected 0 ohms

Checks:
Full throttle enrichment switch.

Possible cause of Problem:
Misadjusted throttle switch or accelerator cable.

5 Cylinder Turbo

Specifications:
With accelerator pressed to floor 0 ohms

Checks:
Full throttle enrichment switch.

Possible cause of Problem:
Misadjusted throttle switch or accelerator cable.





CONNECT AN OHMMETER TO TERMINAL: # 12 and Ground

All 5 Cylinder Engine (except 1979)

Specifications:
Engine below 68° F 0 ohms
Engine above 77° F Infinite ohms

Checks:
Temperature switch for cold enrichment.

Possible cause of Problem:
Defective temperature switch, loose or corroded ground.

Specifications:
Cranking and temperature switches disconnected 0 ohms

Checks:
Start enrichment relay.

Possible cause of Problem:
Defective enrichment relay.





CONNECT AN OHMMETER TO TERMINAL: # 16 and Ground

Specifications:
0 ohms

Checks:
Ground circuit.

Possible cause of Problem:
Loose or corroded ground connection.





CONNECT AN OHMMETER TO TERMINAL: # 8 and Ground

Specifications:
Engine running approximately 12 volts

Checks:
Voltage supply to control unit.

Possible cause of Problem:
Defective voltage supply relay.





CONNECT AN OHMMETER TO TERMINAL: # 15 and Ground

Specifications:
Engine running approximately 12 volts

Checks:
Frequency valve circuit.

Possible cause of Problem:
Defective voltage supply relay, electrical defect in frequency valve.