Quantum L4-1715cc 1.7L SOHC (1983)
Oxygen Sensor: Testing and Inspection
1.
Connect a dwell or duty cycle meter (Siemens 451 or equivalent) to oxygen sensor test connection located near the right strut tower in the engine
compartment. Connect the positive lead to the blue/white wire, and the negative lead to ground. When performing test, do not connect any
other test leads to engine.
2.
Disconnect coil wire from distributor cap and connect to ground.
3.
Remove fuel pump relay from fuse panel and install jumper wire (US 4480/3 or equivalent), ensuring that switch is in off position.
4.
Turn jumper wire switch on. If frequency valve makes buzzing sound, proceed to step 12. If not, proceed to step 5.
5.
Disconnect electrical connector at frequency valve.
6.
Check contact pins and socket of frequency valve for proper position and damage, repairing as necessary.
7.
Connect test light across terminals of frequency valve.
8.
If test light does not illuminate, check wiring of frequency valve and voltage supply of oxygen sensor relay and control unit.
9.
If wiring and voltage supply are satisfactory, replace oxygen sensor relay.
10.
If test light still does not illuminate, replace control unit.
11.
Connect ohmmeter across terminals of frequency valve. If ohmmeter does not read 2-3 ohms, replace frequency valve.
12.
Connect jumper wire across terminals of thermo switch electrical connector.
13.
If tester reading is not 78-82% and steady, check wiring and check for improperly connected multi-point connector at control unit.
14.
If wiring is satisfactory, replace control unit.
15.
Remove jumper wire and disconnect electrical connector at thermo switch. Tester must read 48-52% steady.
16.
Connect ohmmeter across terminals of thermo switch. If ohmmeter does not read infinite ohms with thermo switch temperature above 30°C (86°F)
and zero ohms with thermo switch temperature below 20°C ( 68°F), replace thermo switch.
17.
Disconnect electrical connectors at oxygen sensor and ground green wire.
18.
If tester does not read at least 87%, check wiring.
19.
If wiring is satisfactory, replace control unit.
20.
Connect green wire to positive terminal of 1.5 volt "D" battery and connect battery negative terminal to ground.
21.
If tester does not read less than 20%, check wiring.
22.
If wiring is satisfactory, replace control unit.
23.
Disconnect breather hoses at valve cover and position hoses so that fresh air can enter.
24.
Connect electrical connector at oxygen sensor and connect coil wire at distributor cap.
25.
Start engine and run at 2500 RPM for at least 2 minutes.
26.
Check whether tester reading fluctuates at idle speed.
27.
If tester reading is constant at approximately 13% or 87%, adjust CO level to specifications.
28.
If reading is now 50%, still does not fluctuate or is constant at 13% or 87%, and control unit is operating properly, replace oxygen sensor.
29.
Connect electrical connectors at thermo switch, connect breather hoses at valve cover, remove jumper wire and connect connector at control
pressure regulator.
