Components, Wiring

Remove the panels beneath the dashboard to left and right as well as footwell panels.
Remove the glove compartment.

Check The Ground Connections At Control Unit.





Make sure that the wiring is securely connected.

IMPORTANT: Ignition must be off when disconnecting/connecting connector.

Turn Off Ignition. Disconnect Connector From Control Unit.





Lift catch upwards and swing connector downwards.

Remove Protective Cover From Connector.

Removing Protective Cover:

IMPORTANT:
- Never insert instrument probes into front of connectors. Experience has shown that this can cause damage and give rise to faults.
- Check terminals through the holes at the side of the connector. Only use sufficient pressure to make good electrical contact.
- The terminal numbers are stamped on side of connector.

Check Ground Connections





Connect an ohmmeter between ground and:
- terminal 5 (F-engine)
- terminal 11
- terminal 19
- terminal 25
Resistance should be 0 in all cases.
The wires are grounded via the intake manifold.

Check Lambda Sond Shielding Wire (F-Engine)
Check that the wire is connected to terminal "5".

Check That The Test Points Are Not Grounded





Connect an ohmmeter between ground and:
- terminal 12
To obtain a true reading at terminal 12, also remove the connector for the ignition system control unit to the left-hand side of the pedals. If this is connected a resistance will be indicated.
- terminal 22 (F-engine)
Resistance should be infinite Y) in both cases.

Constant idling speed system (CIS) = red/white (1)
Lambda sond system = green/white (2)

Check Engine Speed Signal From Ignition System Control Unit





Connect a voltmeter between ground and terminal 1.
Operate starter motor. Voltmeter should register (indicate a voltage present).

Check Current Supply.





Turn on ignition.
Connect a voltmeter between ground and terminal 18.
Voltmeter should show battery voltage.
Check for voltage when operating starter motor.
Turn off ignition.

Check Fuel Injection Relay





Connect a voltmeter between earth and control unit terminal "9".
Ground terminal "21".
Relay should complete circuit and meter show battery voltage.

Check Pump Relay





Ground terminal "21" so that main relay is closed.
Ground terminal "17". The pump relay should now close and the fuel pumps start.
Connect a voltmeter between ground and terminal "8" and the 25 pole connector to right of A-post.
Voltmeter should show battery voltage.
Remove ground wire on terminal "17".

Check Air Mass Meter





Ground control unit terminal "21".
The fuel injection relay should switch on.







Remove rubber cover from air mass meter connector so that the wires are exposed.

Connect Voltmeter.





Connect voltmeter between ground and air mass meter terminal "+5", and between terminal "1".
In both cases the voltmeter should show battery voltage.
Remove the link between terminal 21 and ground.

Check Air Mass Meter.





Connect ohmmeter between terminals "6" and "7".
Resistance should be approx. 3 - 4 ohms.
Connect ohmmeter between terminals "6" and "14".
Resistance should be between 0 and 1,000 ohms depending on the position of CO adjustment screw.







Connect a bridge wire from BL-Y to GN-R

CHECK INJECTORS
Connect an ohmmeter between terminal "13" on control unit and terminal "9" on 25-pole connector.
Resistance should be approx. 2.6 - 2.7 ohms.





If resistance is:
- approx. 3.2 ohms (one injector or lead is defective).
- approx. 4.0 ohms (two injectors or leads are defective).
- approx. 5.3 ohms (three injectors or leads are defective).
- approx. 8.0 ohms (four injectors or leads are defective).
- approx. 16.0 ohms (five injectors or leads are defective).

If injectors are defective:
Remove connector from each injector and test separately.
The resistance for each injector should be 16 ohms. Leave bridge wire in place.

Check Air Control Valve





Connect ohmmeter between terminal "9" on the 25 pole connector and terminals "23" and "10" respectively on the control unit.
Resistance in both cases should be approx. 20 ohms at 20°C (68°F)
Remove bridge wire.

Check Preheating Resistor In Lambda Sond (F-Engine).





Connect ohmmeter between ground and terminal "8" of 25 pole connector.
Resistance of cold Lambda sond (20°C =68°F) should be 3 ohms.
Resistance of warm Lambda sond (over 350°C =662°F) should be 13 ohms.

Check Coolant Temperature Sensor





Connect ohmmeter between ground and terminal "2".
Resistance is temperature-dependant, see below.

Resistance at:
-10°C(14°F) 8260-10560 ohms
+2O°C(68°F) 2280-2720 ohms
+80°C(176°F) 290-364 ohms

If incorrect:
- Check resistance at sensor to see if fault is due to sensor or wiring.
- Check ground wire connected to intake manifold.

Check Throttle Switches





Connect ohmmeter between ground and terminal 3 to check idling position switch.
Resistance should be 0 ohms.
Depress accelerator pedal slightly. Resistance should then be infinite (switch opens).
Connect an ohmmeter between ground and terminal 12 to check full throttle switch. Ohmmeter should show infinite resistance, switch is opened. F-engine shows resistance on account of connection to the ignition system. (Over 1000 ohms).
Depress accelerator pedal as far as possible. Resistance should be 0 ohms.

If incorrect:
- Measure resistance at switch to see if fault is due to the switch or wiring.
- Check ground wire, connected to inlet manifold.

Assemble Connector. Connect Connector To Control Unit





IMPORTANT: Make sure that rubber connector cover is replaced prior to connection to the control unit.

IMPORTANT: Ignition must be off when connecting/disconnecting connector.

Start engine
If engine does not start, test with a new control unit.

Connect Co Meter (F-Engine)





Connect CO-meter using 5151 to outlet in front of catalytic converter.

Warm Up Engine

Check Lambda Sond (F-Engine)





Disassemble Lambda sond connector. Ground the wire leading to control unit. CO content should increase to show that the control unit and wiring are fault-free.
Connect voltmeter to Lambda sond. Voltmeter should deflect, showing that the Lambda sond is functioning. At the specified CO content the voltage should be approx. 0.5 Volts.
Assemble Lambda sond connector.

Check Burn-off Current Of Air Mass Meter





NOTE: Engine must be warm. Coolant temperature greater than 60°C (140°F).

Remove rubber cover from air mass meter connector (connector should be connected to air mass meter).
Connect voltmeter between terminals "1" and "4".
Increase engine speed to over 35 r/s (2.100rpm). Turn off engine. After approx. 4 seconds the meter should deflect for approx. one second (=burn off).
Disconnect voltmeter.
Install rubber cover.

Check/adjust Co-content.
If No Faults Are Found During Fault Tracing (all Faults Discovered Having Been Remedied) And Engine Still Runs Unevenly.





Install a new control unit.
Remove test equipment.
Replace central electrical unit, control unit, panels etc.