Neither tune-up nor troubleshooting can be considered independently since each has direct bearing on the other.
An engine tune-up is a service designed to restore the maximum capability of power, performance, economy and reliability in an engine, and, at the same time, assure the owner of a complete check and more lasting results in efficiency and trouble-free performance. Engine tune-up becomes increasingly important each year, to ensure that pollutant levels are in compliance with federal emissions standards.
A complete tune-up should be performed every 12,000 miles or twelve months, whichever comes first. This interval should be halved if the vehicle is operated under severe conditions, such as trailer towing, prolonged idling, continual stop and start driving, or if starting or running problems are noticed. It is assumed that the routine maintenance described in Section 1 has been kept up, as this will have a decided effect on the results of a tune-up. All of the applicable steps of a tune-up should be followed in order, as the result is a cumulative one.
If the specifications on the tune-up sticker in the engine compartment disagree with the Tune-Up Specifications chart in this section, the figures on the sticker must be used. The sticker often reflects changes made during the production run.
It is advisable to follow a definite and thorough tune-up procedure. Tune-up consists of three separate steps: Analysis, the process of determining whether normal wear is responsible for performance loss, and whether parts require replacement or service; Parts Replacement or Service; and Adjustment, where engine adjustments are returned to the original factory specifications.
The extent of an engine tune-up is usually determined by the length of time since the previous service, although the type of driving and the general mechanical condition of the engine must be considered. Specific maintenance should also be performed at regular intervals, depending on operating conditions.
It is advisable to read the entire section before beginning a tune-up, although those who are more familiar with tune-up procedures may wish to go directly to the instructions.
Tune up time is also a good time to look around the engine compartment for potential problems, such as fuel and oil leaks, cracking or hard radiator or heater hoses, loose or frayed belts, loose wire connections, etc.
CAUTION
When working around a running engine, always be certain there is plenty of ventilation.
Make sure the transmission is in Neutral (unless otherwise specified) and the
parking brake is fully applied. Always keep hands, hair, and clothing away from
the fan, hot manifolds and radiator. Remove any jewelry or neckties. When the
engine is running, do not grasp the spark plug wires, distributor cap or coil
wire, as a shock in excess of 20,000 volts may result. Whenever working around
the distributor, even if the engine is not running, make sure that the ignition
is switched off. Removing or disturbing the distributor cap on an electronic
ignition system with the ignition switch ``on'' can often cause the system to
fire.