How it works

What can EGT tell you? EGT gives you an excellent picture of the health of your engine. Here is a brief summary of some of the problems it can detect.

Condition	Typical Problem
EGT rises more than 100 degrees	Pre-ignition -
EGT increase in one cylinder by 50-100 degrees F	Fouled spark plug or faulty ignition Intake manifold leak
EGT increase in all cylinders	Magneto failure or incorrect (overly retarded) ignition timing.
EGT decrease in all cylinders	Air filter restriction Carburetor ice Overly advance ignition timing
EGT decrease in one cylinder	Intake valve low compression
Loss of EGT in one cylinder during Magneto Check	Fouled spark plug or faulty ignition
Hard to find peak EGT	Detonation due to low fuel octane Low energy ignition or wrong spark plugs or gap