Engine Starting — Checks (Hyundai Tucson LM)

The engine started and works properly

1. Before starting the engine, it is necessary to set the gearbox selector lever (automatic transmission) to the "P" position, or to the "N" position if the transmission is manual.

2. It is necessary to check the operability of the brake system vacuum booster. To do this, press the brake pedal and start the engine, while the brake pedal should move a little due to the force of the foot, in this case the vacuum booster functions normally. If the brake pedal does not move when starting, it is recommended to contact a service station for a more detailed diagnosis of the car.

3. Modern cars are equipped with electronic control units (ECU), so there is no need to hold the accelerator pedal down when starting. The electronics will automatically increase the engine speed for faster warm-up, then reduce it to normal idle speed.

4. When starting, some indicators of individual vehicle systems light up, at this moment self-diagnostics of these systems are performed, after a few seconds the indicators should go out. If any of the indicators do not go out, you should refer to the section "Operation of the vehicle" in this manual or to a service station.

5. In winter, for cars with a manual transmission, to simplify starting the engine, before starting it is necessary to press the clutch pedal. If a diesel engine is installed, the car may be equipped with a pre-heating system, which is turned on automatically before starting, and a special indicator lights up, after which you can start the engine.



6. It is advisable, after the engine has started successfully, to open the hood and inspect all the main engine components to ensure there are no leaks (at the main mating points: the cylinder head to the cylinder block, the oil pan to the cylinder block, the gearbox to the engine). Also check the coolant and brake fluid levels in the expansion tanks. If necessary, top up to the required level.

7. Check the operation of all elements of the lighting system. If any faults are detected, see the chapter "Electrical equipment" or contact a service station. You should check:

• a) Headlights (low/high beam headlights/fog lights).
• b) Direction indicators and indicator repeaters (front and rear).
• c) Rear brake lights, rear fog light and reversing light of the vehicle.

The engine does not start, the crankshaft does not turn

1. Check the battery charge level.

2. Check and ensure that the electrical wiring terminals are properly connected to the battery (see the chapter "Operating the vehicle"). Also check the electrical wiring terminals for oxidation (clean the terminals if necessary).

3. Make sure the spark plug high-voltage wires are connected correctly. Also check the ignition coil wire(s).

4. Check the starting system fuses (see below "Actions in an emergency").

5. Check that the electrical wiring is connected correctly to the starter of the starting system.

6. Check the technical condition of the spark plugs (see figure below).

7. Check the ignition system fuses (see below "Actions in an emergency").



8. Using a hydrometer, measure the density of the electrolyte in each cell of the battery (see the chapter "Engine electrical equipment").

9. Using a voltmeter, measure the voltage at the battery terminals.

10. Check the technical condition of the starter (see chapter "Engine electrical equipment").

The engine does not start, the crankshaft turns

1. Check the fuel level in the fuel tank. Be careful and cautious, as some models are equipped with electric fuel pumps that are lubricated by the fuel itself, so if the fuel is completely consumed, the pump will run "dry", which can lead to its failure. It should also be taken into account that the low fuel indicator lamp lights up if there is 5-8 liters of fuel left in the tank.

2. Check and make sure that the electrical wiring terminals are connected to the battery properly (see the chapter "Operating the vehicle"). Also check the electrical wiring terminals for oxidation (clean the terminals if necessary). If the terminals are oxidized, the crankshaft may turn very slowly and stop.

3. Alternatively, a situation may arise when the engine "picks up" (starts, turns over a few revolutions and stalls), but does not start. The reason may be an air leak in one of the intake system elements (see the chapter "Intake and exhaust system"). Air leakage is possible from the following points where the intake system elements are connected:

• a) The place where the throttle body is attached to the air duct (towards the intake manifold).
• b) The place where the air duct is attached to the intake manifold.
• c) Connection of the intake manifold to the cylinder head.
• d) Also, on some vehicles, there may be a leak due to a loose intake air temperature sensor.

4. Check the engine management system sensors.



Modern engine management systems use many sensors that read information about certain parameters of a mechanism or system and send signals to the electronic control unit (ECU/ECM/PCM), all this is done to optimize and improve engine operating processes. However, there are sensors that, if they fail, will indirectly affect operation, while the engine will continue to operate (fuel consumption will change and/or power will decrease, some interruptions in operation are possible), and the "CHECK ENGINE" indicator will light up on the instrument panel . There are also several main sensors, if they fail, the engine will not start, namely:

• a) Oxygen excess sensor (lambda probe). On modern cars it is installed before and after the catalytic converter (see the chapter "Engine management system").
• b) Crankshaft position sensor (see chapter "Engine mechanical part"). It is installed either above the flywheel at the rear of the engine or at the front of the engine.
• c) Mass air flow sensor. It is installed in the air duct of the intake system, before the throttle valve (see the chapter "Engine management system").

5. In winter (at the first morning start after a night in the garage or in the parking lot), the crankshaft may turn very slowly, insufficient to start the engine. The reason may be (provided that all other systems and elements are in good working order) freezing of the battery. To warm up the battery, turn on the high beam headlights for 1-2 minutes. Then try to start the engine again, if the engine does not start, see the possible reasons above. If the car is equipped with a diesel engine, a possible reason may be the formation of paraffin plugs in the fuel lines and fuel channels (this problem is typical for cars that are idle for a long time in an unheated parking lot).



6. If the car has been parked overnight in an open area in winter, then starting may be difficult due to thickening of the engine and transmission oil.

The engine starts but runs intermittently

1. Malfunction of the fuel system (see the chapter "Fuel system"). Malfunctions may be caused by a faulty fuel pump (high-pressure fuel pump, for diesel engines), air in the fuel lines, contamination of the fuel injector nozzles, heavy carbon deposits on the injector nozzles (diesel engines). All work related to the fuel system components is recommended to be performed at specialized service stations.

2. The cause may be an air leak in one of the intake system elements (see the chapter "Intake and exhaust system"). Air leakage is possible from the following points where the intake system elements are connected:

• a) The place where the throttle body is attached to the air duct (towards the intake manifold).
• b) The place where the air duct is attached to the intake manifold.
• c) Connection of the intake manifold to the cylinder head.

3. Malfunctions in the ignition system (petrol only). In this case, work related to the ignition system elements is recommended to be performed at specialized service stations. You can check the following yourself:

• a) Correct connection of high-voltage wires. Wires should fit tightly on spark plug tips and ignition coils.
• b) Technical condition of spark plugs and compliance of installed spark plugs with technical requirements of the car manufacturer. Also, carbon deposits or deposits on spark plug electrodes can be used to determine what malfunctions have occurred in the engine operation (see figure).

Note: There are two main types of candles: hot and cold.

• c) Check the quality of the fuel being poured.

3a. Malfunction of the high-pressure fuel pump (HPFP) associated with a shift in the start of injection and fuel injection time. The cause may be a shift in the drive sprockets of the HPFP (provided that the pump was removed and installed) relative to the drive chain or belt.

4. Violation of the valve timing. In this case, the engine may continue to operate, but with increased fuel consumption and a large loss of power. There are many reasons that can lead to such a violation, but there are two main ones:

• a) When replacing the timing chain/belt, the phases were displaced.
• b) Malfunctions in the electronic engine control unit (ECU).

Note: It is recommended that the above faults be corrected at a service station.

5. Incorrect ignition timing (see "Explanatory Dictionary"). If the ignition timing has shifted to a later value, then engine misfires may be accompanied by pops in the vehicle's exhaust system, as well as black smoke from the exhaust pipe. In this case, it is necessary to stop the engine as quickly as possible, since unburned fuel in the cylinders will burn out in the catalytic converter, which may lead to its failure. If, during engine misfires at idle, pops are heard in the intake manifold, this indicates that the angle has shifted to an earlier ignition zone. Incorrect ignition timing entails serious consequences that may arise as a result of overloading individual elements, units and systems of the engine.

6. Faults in the charging system. In this case, the indicator on the instrument panel in the passenger compartment will light up after starting the engine, indicating that the battery is not charging . In this case, it is necessary to check the places where the electrical wiring is connected to the generator. If the wiring is connected properly, it is necessary to contact the service station.

7. If blue smoke comes out of the exhaust pipe when the engine is running, the cause may be engine oil getting into the cylinders (through the valve bushings or through the piston rings, see the chapter "Mechanical part: engine"), which causes carbon deposits to form on the pistons, spark plugs and injectors, as a result of which the engine starts to run intermittently. In this case, you need to contact a service station to perform repair work.



For diesel engines:

If black smoke comes out of the exhaust pipe and the engine runs rough, the cause may be a loose valve in the injector nozzle, which leads to fuel leaks into the cylinder.

8. Also, engine performance may be impaired due to reduced compression in one or more engine cylinders (see the chapter "Mechanical part of the engine").