Contents: Minimum settings ↡ General settings ↡
The term "tuning" is used in this manual to refer to a set of procedures rather than a single procedure.
If the routine maintenance schedule is strictly followed from the date of purchase, with frequent checks of fluid levels and condition of high wear components as suggested in this manual, the engine will remain in good working order for a long time and the need for any additional work will be kept to a minimum.
More often, however, the engine is not running efficiently due to neglect of regular maintenance. This happens even more often when buying a used car, the owners of which did not bother with frequent and regular checks and maintenance. In this case, in addition to the usual routine maintenance procedures, it will be necessary to tune the engine.
The first step in any tuning or diagnostic procedure to improve engine performance is to check the compression ratio in the cylinders. Checking the compression (refer to Chapter Engine) will help determine the condition of the internal engine components and should serve as a guide when performing tune-ups and repairs. If, for example, a compression ratio check indicates severe internal engine wear, a simple tune-up will not improve its performance and will be a waste of time and money. Since the compression ratio check procedure is so important, it should be performed by a specialist who has the equipment specifically designed for this purpose.
To bring the engine into good working order, the following procedures are most often required:
Minimum settings
- Checking the level and condition of all fluids associated with engine operation (see Section Checking fluid levels, leak monitoring).
- Checking the condition of all hoses in the engine compartment (see Section Checking the condition and replacing engine compartment hoses, localizing leaks).
- Checking the condition and adjusting the tension of the accessory drive belts (see Section Checking the condition of multi-rib belts for auxiliary drive units and the Head Engine).
- Cleaning, inspection and checking the battery charge level (see Section Checking battery condition, care and charging).
- Replacing spark plugs (petrol models - see Section Checking and replacing spark plugs, checking the condition of high-voltage wires (petrol models))/glow (diesel models - see Section Replacing glow plugs (diesel models)).
- Inspection of high-voltage electrical wiring (see Section Checking and replacing spark plugs, checking the condition of high-voltage wires (petrol models)).
- Checking the condition of the air cleaner filter element (see Chapter Fuel and exhaust systems).
- Checking the condition of the cooling system components (see Sections Checking the condition and replacing engine compartment hoses, localizing leaks and Checking the functioning of the cooling system and frost resistance of the coolant, replacing the liquid).
General settings
In addition to the settings listed in the previous list:
- Checking the condition of ignition system components (petrol models)/preheating (diesel models) (See Chapter Engine electrical systems).
- Checking the condition of the charging system components (see Chapter Engine electrical systems).
- Checking the condition of the power supply system components (see Chapter Fuel and exhaust systems).
- Replacement of high voltage electrical wiring.