Twin Cam Engine — Control Operations (Hyundai Sonata Y3)

Contents: Checking the idle speed ⇓ Cleaning the throttle valve surface…⇓ Checking the fuel pump ⇓ Checking fuel pressure ⇓

Checking the idle speed

Verification conditions

The engine coolant temperature should be 80-95°C
Lights, electric cooling fan and all auxiliary devices are switched off
The gear shift lever (or selector) is in neutral position ("P" or "N" for A/T vehicles)
The steering wheel is in the straight-ahead position (power steering).

1. Install a tachometer or connect a scan tool to the data acquisition line in the fuse box.

2. Ground the spark advance terminal.

3. Start the engine and let it idle.

4. Check the ignition timing and adjust it if necessary.

Setting the ignition timing - 5°±2° before TDC (idle)

5. Disconnect the ground wire.

6. Wait 2 minutes for the engine to idle.

7. Check the idle speed.

Idle speed: 750±100 rpm.

Note: Idle speed control is not usually required since the system controls the idle speed.

8. If the idle speed is out of range, adjust it with the adjusting screw (BP) to the standard value.

Note: If the engine stalls, it may be due to deposits on the throttle surface.

Note: If the engine stalls, it may be due to deposits on the throttle surface.

9. Turn the ignition switch to the "OFF" position.

10. If the scanning device is not used, disconnect the data line connector.

Cleaning the throttle valve surface from sediment

1. Warm up the engine and then turn it off.

2. Remove the air intake hose from the throttle body.

3. Close the bypass channel inlet hole in the valve body with a plug.

3. Close the bypass channel inlet hole in the valve body with a plug.

4. Spray cleaning solvent onto the throttle body through the inlet and allow to soak for approximately 5 minutes.

5. Start the engine and let it idle, increasing its speed several times.

6. Repeat the procedures specified in points 4 and 5.

7. Remove the plug in the bypass channel.

8. Connect the air inlet hose.

9. Disconnect the wire connecting the battery to the ground for more than 10 seconds.

10. Adjust the idle speed (using the adjustment screw).

10. Adjust the idle speed (using the adjustment screw).

Checking the fuel pump

1. Turn the ignition switch to the "OFF" position.

2. Apply battery voltage to the fuel pump drive to check if the pump is working.

Note: The fuel pump is located in the tank and therefore its noise is difficult to hear unless the fuel filler cap is removed.

3. Pinch the hose with your fingers to feel the presence of fuel pressure.

Checking fuel pressure

1. Reduce the pressure in the fuel supply line and hoses as follows.

(The original text is available on the website: «HyundaiBook»)

Disconnect the fuel pump wiring harness.
Start the engine and after it stops by itself, turn the ignition switch to the "OFF" position
Disconnect the negative battery terminal
Connect the fuel pump wiring harness.

2. Disconnect the high pressure hose from the fuel supply side.

Caution: Close the pipe connections to prevent fuel splashing caused by residual pressure in the fuel supply line.

3. Using the adapter, install the fuel pressure measuring device and connect it to the high pressure hose.

4. Connect the negative (-) battery terminal.

5. Apply battery voltage to the fuel pump drive and turn off the pump. After fuel pressure is created, check for leaks from the device.

6. Disconnect the vacuum hose from the pressure regulator and plug the end of the hose. Measure the fuel pressure at idle.

Standard value is 320-340 kPa

7. Measure the fuel pressure while the vacuum hose is connected to the pressure regulator.

The standard value is approximately 270 kPa

8. If the measurement results are not within the standard value, take corrective measures based on the following table.

9. Turn off the engine and check for a change in the fuel pressure gauge reading, which should be maintained for approximately 5 minutes. If the reading drops, note the degree of decrease. Determine and correct the cause according to the table below.