VISUAL INSPECTION
Visually inspect all wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections if necessary. Inspect air induction system for possible vacuum leaks.
MECHANICAL INSPECTION
| WARNING | DO NOT use ignition switch during compression tests on fuel injected engines. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking mode, which can create fire hazard and contaminate engine oiling system. |
Note. Ensure battery is fully charged to obtain specified cranking speed.
Note. If cylinder compression in one or more cylinders is low, repeat inspection using a small amount of oil poured into each cylinder. If compression pressure increases, piston rings may be worn or damaged. If compression pressure does not increase, a valve may be sticking or seating improperly. If compression in any 2 adjacent cylinders is low and does not change after oil is added, cylinder head gasket may be leaking.
See also:
• ON-VEHICLE ADJUSTMENTS