ENGINE TUNE-UP

An engine tune-up is a series of procedures that restore optimum en-gine performance, reduce exhaust emissions, increase fuel mileage, and prolong the useful life of the engine. It can save you a long walk home or an expensive tow job.

Since an engine tune-up is one of the most important elements of proper car care, it should be performed at regular intervals rather than after a failure occurs. If you are an average driver, every 10,000 miles is a good rule-of-thumb schedule for periodic engine tune-ups. If your car is used less frequently, 4,000-5,000 miles a year, then you must use a different schedule for tune-ups;one based on time rather than miles. In this case, a tune-up once a year will keep your car running at peak efficiency. If you put extremely high mileage on your car 10,000 or 50,000 miles a year;your tune-up schedule should be every 15,000 miles or so.

If one of the following warning signs is present, your engine probably needs a tune-up: 1. Engine performance is noticeably sluggish. 2. The engine consistently stalls. 3. The engine is hard to start. 4. The engine misfires. 5. Engine hesitation or surge is noticeable, especially in high gear at highway speeds.

Before beginning any tune-up, it is recommended that you care-fully read through the instructions and study the diagrams in this chapter at least once and preferably twice to get an overview of what you will be doing and what you can expect next as you proceed from step to step. And since on most modern cars the emission control system is directly related to the engine tune-up, you should read the chapter on emission control before attempting to tune up your engine.

Also, be sure to read the paragraphs on parts and equipment be-fore beginning. Have the right tools, equipment, and parts on hand before you begin. There is nothing more frustrating than beginning a job and then finding out that you do not have everything you need.

Engine tune-up steps

Before getting into any of the spe-cific operations, it will be helpful for you to know all the steps involved in a complete basic engine tune-up. The following list is just that-a list. No explanatory steps are included here because each will be thoroughly described in detail on subsequent pages of this chapter, as indicated. Carry out the first eight steps in the order indicated. The order of the remaining operations may be varied.

Note: Before you begin any tune-up, you must determine whether your car's engine is equipped with a conventional or an electronic igni-that the electronic ignition system denser. Therefore, if your car has dwell. All the other service pro- A basic engine tune-up consists of the following steps:

1.Remove the spark plugs.
2.Perform a compression test.
3.Service the spark plugs.
4.Replace the distributor cap and rotor.
5.Service the distributor.
6.Check the ignition wires with an ohmmeter.
7.Replace the ignition points and condenser.
8.Service the battery and battery cables (see Chapter 3 for detailed instructions).
9.Service the carburetor, choke, and linkages.
10.Replace the fuel filter.
11.Replace the air filter and crankcase filter.
12.Service the emission controls, manifold heat control valve, positive crankcase ventilation (PCV) valve, and exhaust gas re-circulation (EGR) valve.
13.Check all the vacuum lines and hoses.

Safety precautions

Before starting the tune-up, be sure to observe the following precautions, both for your own safety and that of your vehicle:
1. Park your car on level ground.
2. Place the shift lever in the Park position on automatic transmission-equipped vehicles, or in Neutral for manual shift cars.
3. Apply the parking brake. Caution: When doing a tune-up, never run your engine in an en-closed, poorly ventilated area, because of the danger of carbon monoxide fumes.

Tools and equipment:

1. Droplight.
2. Screwdriver set, 4-inch, 8-inch, and 12-inch.
3. Pliers.
4. Spark plug socket and ratchet, with 3/8-inch drive and 1-inch, 3-inch, and 6-inch extensions.
5. Compression testing gauge.
6. Remote starter switch.
7. Feeler gauges-flat type for ig­nition point gap settings, wire type for spark plug gap.
8. Allen wrench set.
9. Distributor wrench or appropri­ate socket with long extension and swivel joint.
10. Ignition wrench.
11. Torque wrench.
12. Tach-dwell meter.
13. Ohmmeter and voltmeter.
14. Timing light.
15. Hand cloths.
16. Fender covers.
17. Breaker cam lube.
18. Combination wrenches.
19. Goggles.
20. Hand vacuum pump.
21. Length of 1/4-inch hose.
22. 14-inch jumper wire with alliga­tor clips.
23. Masking tape.
24. Spark plug wire remover.
25. Hand oil squirt can.
26. Wire hand brush.
    27.Piece of chalk or scribe.

Parts you may need:
To make certain you get the right parts for your particular engine, consult your owner's manual, or the manufacturer's information plate or decal located under the hood or on the firewall. Your neighborhood auto parts supply store can also usually help you.
You will need the following parts to tune up your car:

1. Spark plugs.
2. Ignition breaker point assembly.
3. Condenser.
4. Fuel filter.
5. Air filter.
6. Positive crankcase ventilation (PCV) valve.
7. Crankcase filter (if required).
8. Distributor cap and rotor (if re­quired).
9. Ignition wires (if worn).