Note. Before performing any operation that requires the battery to be disconnected on vehicles equipped with a Delco Loc II audio system, verify that the lockout feature is disabled.
Term "adjustment" in this case it is used to refer to a combination of separate operations, and not to any one particular procedure. If, while the vehicle is still new, the maintenance schedule is carefully followed and proper checks are performed frequently, as suggested in this manual, the engine will be kept in good condition and the need for additional adjustments will be minimal.
When operating a used car, in addition to the indicated intervals for regular maintenance, it is likely that there will be a need for additional operations to adjust the engine.
The first step in any adjustment or diagnostic procedure is to check the compression in the cylinders (see chapter 2), which will help determine the condition of the internal parts of the engine. It requires special equipment to carry it out. If, for example, a compression test shows serious internal wear on the engine, a simple adjustment will not improve its performance.
Below is a list of procedures that are most often needed to bring a badly running engine back to normal.
Preliminary adjustment
- Check all fluids related to the engine (section 4)
- Clean, inspect and test the battery (section 8)
- Check and adjust the tension of the drive belts (section 21)
- Replace spark plugs (section 32)
- Check the wires going to the spark plugs (section 33)
- Check crankcase ventilation valve (section 30)
- Check the air filter (section 19)
- Check the engine cooling system (section 9)
- Check all underhood hoses (section 10)
Basic adjustment
Complete all of the above, plus:
- Check the exhaust gas recirculation system (chapter 6)
- Check ignition timing (section 34)
- Check battery charging circuit (chapter 5)
- Check the fuel system (section 18)
- Replace air filter (section 19)
- Replace wires to spark plugs (section 33)