Gauging use of Glow Plugs

• Wire and surrounding bottom of plug wet, with like new shiny wire = rich side of optimum power 85%
• Wire and surrounding bottom of plug starting to dry and wire starting to gray = Very close to optimum power 95%
• Wire and surrounding bottom of plug dry, wire totally gray but not distorted optimum power 100%
• Wire and surrounding bottom of plug dry, wire distorted = slightly lean DANGER!
• Wire and surrounding bottom of plug dry, wire broken and distorted or burnt up = extremely lean possible engine damage!