Checks when starting the engine (Skoda Rapid NH1)

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 make it easier to start the engine, you must press the clutch pedal before starting. If a diesel engine is installed, the car may be equipped with a pre-heating system, which turns on automatically before starting, and a special indicator lights up, after which you can start the engine.



6. It is advisable to open the hood after the engine has started successfully and inspect all the main components of the engine to ensure that there are no leaks (at the main mating points: cylinder head to cylinder block, oil pan to cylinder block, gearbox to 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) Headlamps (low/high beam headlights/fog lights).
• b) Direction indicators and indicator repeaters (front and back).
• 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 connected to the battery properly (see chapter "Operation of the vehicle"). Also check the wiring terminals for oxidation (clean terminals if necessary).

3. Make sure that the high-voltage spark plug wires are connected correctly. Also check the wire / coil wires/ignition coils.

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 below picture).

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 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, therefore, if the fuel is completely consumed, the pump will run "dry", which can lead to its breakdown. 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 terminals if necessary). If the terminals are corroded, the crankshaft may turn very slowly and stall.

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

• 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 sensors of the engine management system. 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/ESM/RSM), all this is done to optimize and improve the engine's operating processes. But, there are sensors that, if they fail, will indirectly affect the 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 indicator on the instrument panel will light up "CHECK ENGINE". 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 chapter "Engine management system").
• b) Crankshaft position sensor (see chapter "Mechanical part of the engine"). It is installed either above the flywheel from the rear of the engine, or from the front of the engine.
• c) Mass air flow sensor. It is installed in the air duct of the intake system, in front of the throttle valve (see chapter "Engine management system").

5. In winter (at the first morning start after a night in the garage or in the parking lot) it is possible that the crankshaft turns very slowly, not enough to start the engine. The reason may be (provided that all other systems and components 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 causes above. If the car is equipped with a diesel engine, then a possible cause may be the formation of paraffin plugs in the fuel lines and fuel channels (this violation is typical for cars that are left standing 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. Malfunctions in the fuel system (see chapter "Power supply system"). The cause of malfunctions may be a malfunction of the fuel pump (Fuel injection pump for diesel engines), air in fuel lines, contamination of fuel injector nozzles, heavy carbon deposits on injector nozzles (diesel engines). All work related to fuel system components is recommended to be performed at specialized service stations.



2. The cause may be an air leak in one of the elements of the intake system (see the chapter "Intake and exhaust system").

• a) Air leakage is possible from the following points where the intake system elements are connected.
• b) The place where the throttle body is attached to the air duct (towards the intake manifold).
• c) The place where the air duct is attached to the intake manifold. The connection of the intake manifold with the cylinder head.

Malfunctions in the ignition system (only petrol). When atomic work related to ignition system elements is recommended to be performed at specialized service stations. You can independently check the following:

• a) Correct connection of high-voltage wires. The wires must fit tightly on the spark plug tips and on the 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 picture).

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

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

3a. Malfunction of the fuel injection pump (high pressure fuel pump), associated with a shift in the start of injection and fuel injection time. The cause may be a shift in the fuel injection pump drive sprockets (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) Check the quality of the fuel being poured.
• b) When replacing the drive chain / timing belt (gas distribution mechanism) phase shift occurred. Malfunction of the electronic engine control unit (ECU).

5. Incorrect ignition timing. 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 dashboard in the passenger compartment, after starting the engine, will light up indicating that the battery is not charging. In this case, it is necessary to check the wiring connections to the generator. If the wiring is connected properly, it is necessary to contact a 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 of the engine"), which causes carbon deposits to form on pistons, spark plugs and injectors, causing the engine to run intermittently. In this case, you need to contact a service station to have repairs performed.



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 decreased compression in one or more engine cylinders (see chapter "Mechanical part of the engine").