Contents: Checking the fuel pressure in the…↓ Checking the throttle position sensor ↓ Checking the coolant temperature…↓ Checking the intake air temperature…↓ Checking the resistance of the…↓ Checking the idle speed control valve ↓ Checking and adjusting the throttle…↓ Self-diagnosis ↓
Fig. 15. Placement of elements of the fuel injection control subsystem KSUD "Motronic" on the vehicle "Passat 2,8 VR6": 1 - mass air flow meter; 2 — throttle body; 3 — controller; 4 — intake air temperature sensor; 5 - idle speed controller; 6 — nozzle; 7 - exhaust gas oxygen sensor; 8 — throttle position sensor; 9 — electromagnetic valve of the adsorber.
Before checking the engine idle speed, perform the following operations:
- warm up the engine to an oil temperature of at least 80°C;
- check the correct adjustment of the gap between the spark plug electrodes and the ignition timing;
- make sure the air filter element is in good condition;
- turn off all auxiliary electrical equipment and air conditioning;
- make sure the exhaust system is tight.
Connect the control tachometer according to the operating instructions, start the engine and check the crankshaft speed at idle, which should be within 650-750 rpm.
The crankshaft speed at idle is automatically regulated by the idle speed regulator based on signals from the controller and cannot be adjusted manually.
Connect the gas analyzer according to the operating instructions and check the CO content in the exhaust gases, which should be within 0.3-1.2%.
The CO content in the exhaust gases is regulated automatically by the controller based on signals from the oxygen content sensor in the exhaust gases and is not subject to manual adjustment.
NOTE: The throttle opening is set at the factory and cannot be adjusted during operation.
Checking the fuel pressure in the system
Self-diagnosis code: 2-4-1-3.
Turn off the ignition.
Connect the pressure gauge to the system's measuring pipe (Fig. 12).
Start the engine at idle speed and check the regulated fuel pressure, which should be about 3.5 kgf/cm². Disconnect the vacuum hose from the fuel pressure regulator and check the fuel pressure in the system using a pressure gauge, which should be about 4.0 kgf/cm².
Connect a vacuum hose to the fuel pressure regulator. Turn off the ignition and after 10 minutes check the residual fuel pressure, which should be at least 2.5 kgf/cm².
Checking the throttle position sensor
Self-diagnosis code: 2-2-1-2.
Turn off the ignition.
Disconnect the throttle position sensor connector, connect an ohmmeter to terminals "1" and "2" of the sensor block (Fig. 13) and check the ohmmeter readings, which should be within 1.13-1.15 kOhm.
Slowly open the throttle valve. The resistance on the ohmmeter should increase smoothly.
Connect an ohmmeter to terminals "2" and "3" of the sensor block and check its readings, which should be within 2.68-2.72 kOhm.
Slowly open the throttle valve. The resistance on the ohmmeter should decrease smoothly.
Connect an ohmmeter to terminals "1" and "3" of the sensor block and check its readings, which should be within 1.98-2.02 kOhm.
Checking the coolant temperature sensor
Self-diagnosis code: 2-3-1-2.
Turn off the ignition.
Disconnect the blue connector from the coolant temperature sensor.
Remove the sensor from the engine and immerse it in a container with coolant.
Connect an ohmmeter to the sensor terminals (Fig. 14) and check the sensor resistance, which at a coolant temperature of 20°C should be 2.5 kOhm; at 40°C - 1.25; at 60°C - 0.6 and at 80°C - 0.325 kOhm.
The coolant temperature sensor can be checked without removing it from the engine.
Checking the intake air temperature sensor
Turn off the ignition.
Disconnect the intake air temperature sensor connector and connect an ohmmeter to the sensor terminals (Fig. 16). Measure the sensor resistance, which at an ambient air temperature of 10°C should be 3.5 kOhm; at 20°C - 2.5; at 40°C - 1.25; at 60°C - 0.6 and at 80°C - 0.325 kOhm.
Checking the resistance of the injector windings
Turn off the ignition.
Disconnect the injector connector, connect an ohmmeter to its terminals (Fig. 17) and check its readings, which should be within 15.0-21.4 Ohms.
Checking the idle speed control valve
Turn off the ignition.
Disconnect the idle speed control connector, connect an ohmmeter to its terminals (Fig. 18) and check its readings, which should be within 10-20 Ohms.
Checking and adjusting the throttle damper
Open the throttle valve, then close it until pusher 2 (Fig. 19) touches roller 3.
In this position, using a 3 mm diameter drill, check the gap between stop screw 4 and lever 1.
If it is necessary to adjust the clearance, clamp the drill between the screw and the roller, loosen the lock nut of the stop screw and adjust the position of the damper so that the pusher 2 only slightly touches the roller 3.
Tighten the stop screw lock nut.
Self-diagnosis
Self-diagnosis of the system is performed as specified in the subsection "Self-diagnosis" for KSUD "KE-Motronic", described in the section "16-valve engines", using a controller, in the memory device of which fault codes are written. read using the appropriate equipment Before proceeding with the ROM interrogation. make sure that fuses No.18 and No.21 are intact.
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