System Testing

Following VOLTAGE CHECKS and RESISTANCE CHECKS charts show procedure for checking CIS-E system components from ECU connector. ECU connector terminal numbers are called out in testing procedures. Ignition MUST be off whenever ECU connector is disconnected or reconnected. Use care to avoid any terminal damage when testing, removing or attaching connectors.

Always check all connections used in test procedure. If readings are incorrect, disconnect terminals and determine if wiring or components are at fault. High tension lead should be disconnected at ignition distributor end and connected to ground. Use Digital Multimeter (US 1119 ).

THERMO-TIME SWITCH - OPERATIONAL TIME

Temperature	Seconds
-4°F (-20°C)	5-11
14°F (-10°C)	4-9
32°F (0°C)	3-7.5
50°F (10°C)	2-6.5
68°F (20°C)	1-4
86°F (30°C)	0-2
104°F (40°C)	0

Fig 1: ECU Connector - Terminal PIN Numbering

4000S 4-CYLINDER RESISTANCE CHECKS ⁽¹⁾

Terminal Nos.

Components Checked

Specifications

7 & 8

O2 Sensor Wire Shield

Reading should be infinity ohms. If not, check shielding for short.

8 & 2

O2 Sensor & Wiring

Reading should be zero ohms with Green O2 sensor lead unplugged and grounded. If not, check Green wire for open. Reading should be infinity ohms with O2 sensor lead connected. If not, O2 sensor is defective and should be replaced.

10 & 12

Differential Pressure Reg. & Wiring

Reading should be 17.5-21.5 ohms. If not, check wires 10 and 12. If wiring is good, differential pressure regulator is defective and should be replaced.

14 & 17

Potentiometer & Wiring ⁽²⁾

Reading of less than 1000 or more than 4 k/ohms with airflow sensor plate in rest position. If not, check wires 14, 17 and 18 for open. If wires are good, adjust or replace potentiometer.

17 & 18

Potentiometer & Wiring ⁽²⁾

Reading of less than 1000 or more than 4 k/ohms with airflow sensor plate in rest position. If not, check wires 14, 17 and 18 for open. If wires are good, adjust or replace potentiometer.

21 & 2

Temperature Sensor & Wiring

Reading of 2.5 k/ohms at 68°F (20°C). Resistance reading should be higher at lower temperatures (about 600 ohms with engine warmed up). If not, check for open circuit in wiring. If wiring is good, replace temperature sensor.

⁽¹⁾	TESTING CONDITIONS: Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20k ohm scale. Prevent ohmmeter damage by checking ONLY terminals listed.

⁽²⁾	Potentiometer terminals 1, 2 and 3 are connected respectively to terminals 18, 17 and 14 on ECU connector.

4000S 4-CYLINDER VOLTAGE CHECKS ⁽¹⁾

Terminal Nos.

Components Checked

Specifications

1 & 2

Voltage Supply To ECU

Battery voltage with ignition on. If not, check fuse 24. If fuse good, check open circuit in wiring. Check ground connection on cold start valve.

1 & 15

Ground Connection 2/15

Battery voltage with ignition on. If not, check ground connection bridge in multipoint connector.

1 & 9 ⁽²⁾

Ground Connection 15/9

Battery voltage with ignition on. If not, check ground connection bridge in multipoint connector.

1 & 22 ⁽³⁾

Ground Connection 15/22

Battery voltage with ignition on. If not, check ground connection bridge in multipoint connector.

2 & 24

Wiring Between Starter & ECU

Minimum 8 volts with starter cranking.If not, check wiring for open.

⁽¹⁾	TESTING CONDITIONS: Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector within ignition off. Set multimeter to 20-volt DC scale.

⁽²⁾	On manual transmissions only.

⁽³⁾	On automatic transmissions only.

5000S 5-CYLINDER RESISTANCE CHECKS ⁽¹⁾

Terminal Nos.

Components Checked

Specifications

2 & 22

Ground Bridge

Reading of zero ohms. If not, check for open in bridge across terminals.

2 & 15

Ground Bridge

Reading of zero ohms. If not, check for open in bridge across terminals.

7 & 8

O2 Sensor Wire

Reading of infinity ohms. If not, check for open circuit in O2 sensor lead.

2 & 8

O2 Sensor Wiring

Reading of zero ohms with Green O2 sensor lead unplugged and grounded. If not, check for open in circuit in Green O2 sensor lead.

10 & 12

Differential Pressure Reg. & Wiring

Reading of 17.5-21.5 ohms. If not, check for open in circuit between regulator and ECU. If wiring is good, replace differential pressure regulator.

14 & 17

Potentiometer & Wiring

Reading below 12 k/ohms with airflow sensor plate in rest position and altitude sensor unplugged. If not, check wiring to terminals 14 and 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.

17 & 18

Potentiometer & Wiring

Reading above 35 k/0hms with airflow sensor plate in rest position and altitude sensor unplugged. If not, check wiring to terminals 14 and 17 for opens. If wiring is good, adjust or replace airflow sensor plate potentiometer.

18 & 14

Altitude Sensor

Reading of 21-26 k/ohms with potentiometer unplugged. If not, check for open circuit in wiring. If wiring is good, replace altitude sensor.

11 & 14

Altitude Sensor

Reading of 200-38,000 ohms with potentiometer unplugged. If not, check for open circuit in wiring. If wiring is good, replace altitude sensor.

21 & 2

Temperature Sensor

Reading of 2.5 k/ohms at 68°F (20°C). Resistance reading should be higher at lower temperatures and lower at higher temperatures. If not, check for open circuit in wiring. If wiring is good, replace temperature sensor.

1 & 5

Full Throttle Switch

Reading of zero ohms with switch in full throttle position. Reading of infinity with full throttle switch in closed position. If not, check wiring for open circuit. If wiring is good, adjust or replace full throttle switch.

1 & 13

Idle Switch

Reading of zero ohms with switch in idle position. Reading of infinity with switch in any open throttle position. If not, check wiring for open circuit. If wiring is good, adjust or replace idle switch.

⁽¹⁾	Testing conditions: Disconnect and ground high tension lead at ignition distributor end. Unplug ECU connector with ignition off. Set multimeter to 20-k/ohm scale. Prevent ohmmeter damage by checking ONLY terminals listed.