If the owner of a new car has strictly adhered to the schedule of routine maintenance procedures since the day of its purchase, has performed critical parameter checks frequently enough, and has maintained the required level of lubricating fluids, the engine will very rarely require additional maintenance and repairs (beyond the replacement of components and consumables subject to increased wear).
On the other hand, if regular maintenance procedures are performed carelessly and the established inspection schedules are frequently violated, the engine's efficiency will sooner or later inevitably decrease. The likelihood of such a situation occurring is especially high when purchasing a used car. In such cases, it becomes necessary to perform a set of powertrain adjustments beyond the scope of work on the car's current maintenance.
The first step in tuning or diagnosing a poorly performing engine is always to check the cylinder compression pressure (see Chapter Engine), the analysis of the results of which allows you to assess the general condition of the internal components of the engine and outline a plan for upcoming adjustment and / or restoration work. For example, if a compression pressure check reveals signs of serious internal engine wear, a regular set of adjustments will not be enough to correct the situation, and its implementation will be a waste of time and money. In view of the value of the information obtained as a result of checking the compression pressure, its implementation should be entrusted to a sufficiently experienced and qualified mechanic who has the necessary diagnostic tools.
Below are lists of basic tuning procedures that will restore the efficiency of an engine that is in good mechanical condition.
List of minimum checks and adjustments
- Check the levels of all fluids related to engine operation (see Section Checking fluid levels).
- Clean and check the battery condition (see Section Checking, servicing and charging the battery).
- Check the condition and tension of the drive belts and make adjustments if necessary (see Section Checking the condition, adjusting the tension force and replacing the drive belts).
- Check the condition of all hoses located in the engine compartment (see Section Checking the condition and replacing the hoses located in the engine compartment).
- Check the condition and service the cooling system components (see Section Checking the condition of the cooling system components).
- Check the condition of the air cleaner filter element (see Section Replacing the air cleaner filter element).
- Check the condition of the spark plug wires, cap and distributor rotor (see Section Checking the condition and replacing the spark plug wires, cover and distributor rotor).
- Check the idle speed setting and make the appropriate adjustments if necessary (see Section Replacing air conditioning system filters).
List of the full range of checks and adjustments
In addition to the checks listed above:
- Replace the spark plugs (see Section Checking the condition and replacing spark plugs).
- Check the idle speed adjustment (see Section Checking and adjusting idle speed).
- Replace the air cleaner filter element (see Section Replacing the air cleaner filter element).
- Replace the distributor cap and rotor (see Section Checking the condition and replacing the spark plug wires, cover and distributor rotor).
- Replace the spark plug wires (see Section Checking the condition and replacing the spark plug wires, cover and distributor rotor).
- Check the proper functioning and condition of the power supply system components (See Section Checking the transmission oil level of the manual transmission).