Neither tune-up nor troubleshooting can be considered independently, since each has a direct bearing on the other.
In order to extract the full measure of performance and economy from your engine it is essential that it be properly tuned at regular intervals. A regular tune-up will keep your vehicle's engine running smoothly and will prevent the annoying minor breakdowns and poor performance associated with an untuned engine.
A complete tune-up should be performed every 30,000 miles or two years, whichever comes first. A tune-up check should be performed every 12,000 miles or twelve months. These intervals 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 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.
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.
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; adjustment, where engine adjustments are returned to the original factory specifications.
Troubleshooting is a logical sequence of procedures designed to lead the owner or service man to the particular cause of trouble. The troubleshooting charts in this guide is general in nature, yet specific enough to locate the problem. Service usually comprises two areas: diagnosis, and repair. While the apparent cause of trouble, in many cases, is worn or damaged parts, performance problems are less obvious. The first job is to locate the problem and cause. Once the problem has been isolated, refer to the appropriate section for repair, removal or adjustment procedures.
It is advisable to read the entire chapter before beginning a tune-up, although those who are more familiar with tune-up procedures may wish to go directly to the instructions.