Automotive Tips

Check/Adjust Basic Engine Timing
Correct timing is essential to maintain top performance. Timing refers to when the engine tells each spark plug to fire. A chart under the hood of most cars shows what the timing should be at various RPM levels. Use a timing light to set the timing on any engine (computer-controlled or not) that has a conventional distributor ignition system. Timing cannot be manually adjusted on cars with distributorless ignition systems, but it is important to check computer timing to see if it might be the cause of engine problems. Use an advance timing light such as the Timing Advance Analyzer CP7519 to check whether the computer is "advancing the spark" according to spec as engine speed increases.

Vacuum Leak Test
Leaky vacuum lines can cause problems for any engine. A vacuum pump can be used to check vacuum lines as well as vacuum-operated solenoids and switches.

Engine Vacuum
Use a vacuum gauge to test for proper intake manifold vacuum at idle. Improper vacuum can mean problems with ignition timing, piston rings, valves, valve timing, valve springs, valve guides, manifold leaks and some carburetor adjustments. Even small vacuum leaks can cause hard starting, stalls, and poor engine performance.

Basic Tests
The basic engine has not changed and the computer does not control everything! Compression Test. Use a compression gauge to test for proper compression in each cylinder. Improper compression can cause rough idling or running, backfiring and poor fuel economy. Can also be used to test valve problems, piston rings and timing chain.

Ignition Module Test
Faulty ignition modules can cause no-start problems. Check modules for proper operation.

Battery Voltage Test
Low batteries can cause intermittent problems well before the battery completely dies. Battery voltage should be at least 12.4 volts. Use a voltmeter or battery load tester to check.

Pass Emission Tests
Poorly tuned vehicles may fail state emission testing, requiring costly repairs.

Compression Test
Use a compression gauge to test for proper compression in each cylinder. Improper compression can cause rough idling or running, backfiring and poor fuel economy. Can also be used to test valve problems, piston rings and timing chain.

Cranking System Voltage Test
The cranking system requires at least 8-1/2 to 9 volts to start the engine. Use a voltmeter to test cranking system voltage.

Lighting System Voltage Test
Use a voltmeter to test lighting systems.

Engine rebuilding tips

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