Electrode Gap Bridging

Electrode gap bridging may be traced to loose deposits in the combustion chamber. These deposits accumulate on the spark plugs during continuous stop-and-go driving. When the engine is suddenly subjected to a high torque load, deposits partially liquefy and bridge the gap between electrodes. See Fig 1. This short circuits the electrodes. Spark plugs with electrode gap bridging can be cleaned using standard procedures.

Fig 1: Electrode Gap Bridging

Courtesy of DAIMLERCHRYSLER CORP.