Mechanical Inspection: Compression

WARNING: Fuel injectors are triggered by ignition switch during cranking mode. DO NOT use ignition switch during compression tests. Use remote starter switch to crank engine to prevent fire hazard or contamination to engine's oiling system.

Check engine mechanical condition with compression gauge, vacuum gauge, or engine analyzer. See engine analyzer manual for specific instructions. For compression specifications, see ENGINE COMPRESSION under MECHANICAL CHECKS in SERVICE & ADJUSTMENT SPECIFICATIONS - TRUCKS article.