If any faults are found, you should first check the electrical wires and their connections, and then check the corresponding element.
Checking system elements
The element being tested | Measuring between contacts | Ignition | Meaning | Notes |
| Connection of the electronic control unit EEC IV to ground | 20" and mass "40" and mass "60" and mass | Off | 0 – 2.5 Ohm | |
| Octane number corrector | "5" and "40" "23" and "40" "24" and "40" | Off | The resistance is infinitely large | Before checking, disconnect the connector from the electronic control unit |
| Diagnostic connector input | "17" and "40" | Off | The resistance is infinitely large | |
| Diagnostic connector output | "48" and "40" | Off | The resistance is infinitely large | |
| Module power cable | "37" and "57" | Off | 0 – 2.5 Ohm | |
| Injectors N1 and 2 | "37" and "58" | Off | 6 – 9 Ohm | |
| Nozzles N 3 and 4 | "37" and "59" | Off | 6 – 9 Ohm | |
| Injector relay | "37" and "22" | Off | 50 – 120 Ohm | |
| Idle speed control valve | "37" and "21" | Off | The resistance is infinitely large | Disconnect the valve before testing |
| Valve diode | "21" and "37" | Off | 0 – 2 Ohm | Disconnect the valve before testing |
| Coolant temperature sensor | "7" and "46" | Off | 20 – 100 kOhm | Coolant temperature 20°C |
| Incoming air temperature sensor | "25" and "46" | Off | 15 – 40 kOhm | Temperature 20° – 40°C |
| Throttle Position Sensor | "47" and "46" "47" and "26" | Off | 1.2 – 2 kOhm 3.3 – 5.5 kOhm | |
| TFI Ignition Booster Module IV | "36" and "40" | Off | 2 – 5.5 kOhm | |
| Connecting the TFI IV Ignition Booster Module to Ground | "16" and "40" | Off | 0 – 2.5 kOhm | |
| Power Supply for TFI Ignition Enhancement Module IV | "37" and "40" | Included | 10 – 14 V | |
| Power supply for fuel injectors N1 and 2 | "58" and "40" | Included | 10 – 14 V | |
| Power supply for fuel injectors N 3 and 4 | "59" and "40" | Included | 10 – 14 V | |
| Fuel pump relay | "22" and "40" | Included | 10 – 14 V | |
| Power supply for the memory of the electronic control device EEC IV | "1" and "20" | Included | 10 – 14 V | |
| Crankshaft position sensor | "55" and "56" | Included | 200 – 450 Ohm | |
Speed sensor | "4" and "40" | Included | 0 – 12 V (variable) | Spin the rear wheel |
Checking and adjusting idle speed
Initial conditions
The engine must be warmed up to normal operating temperature. To do this, increase its speed to 2000 rpm and wait for the thermostat valve to open. Do not warm up the engine at idle speed, since during prolonged operation under these conditions the CO content in the exhaust gases will differ from the CO content under normal vehicle operating conditions.
The air filter must be installed and its replacement element must not be too dirty.
The ignition system must be in good technical condition.
Additional air must not enter the engine intake system through leaky connections, damaged vacuum lines, etc.
The engine exhaust system must be sealed.
None of the electrical consumers (headlights, fan motor, rear window heating, etc.) should be switched on.
Checking the number of revolutions
The idle speed in engines equipped with the EEC IV system is controlled by the EEC IV electronic control device and there is no possibility of manual control. For the DOHC engine type N9A, the idle speed should be 875±25 rpm.
Adjustment of CO content
1. Connect the exhaust gas analyzer.
2. Check the CO content at idle, which for a DOHC engine type N9A should be 1.0–1.5%.
3. If necessary, adjust the CO content at idle speed using the CO content adjustment potentiometer.