Bad spark plug symptoms code#

When this occurs, a plug wire’s insulator will become overly brittle, presenting spark energy with a path to ground. Though spark plug wires are insulated quite heavily, and are designed to withstand extensive heat, their typical location within close proximity to an engine’s exhaust manifold makes them ripe for eventual heat degradation. Spark plug wires can actually fail for one of several different reasons. Luckily, this can prove to be quite a helpful diagnostic aid, as misfire DTCs can often be traced back to a specific cylinder.

Bad spark plug symptoms code#

When this occurs, a corresponding misfire code is logged, and a vehicle’s check engine light is illuminated. In many instances, a misfire caused by a faulty spark plug wire will be recognized by a vehicle’s Engine Control Module (ECM). This backfiring is typically accompanied by a certain level of hesitation or power loss when an engine is under a load. In certain cases, the presence of spark plug wire failure will cause an engine to backfire, as a result of incomplete or inefficient combustion. This condition is often most notable under periods of heavy throttle demand and can be felt as a hesitation, or noticeable reduction in power.Ī misfiring engine also tends to present an audible loping noise when under load as well. #2 – MisfireĪnother symptom of a faulty spark plug wire is a noticeable misfire on at least one cylinder. This poor idle results from a relative imbalance from one respective cylinder to the next. This can often be felt when sitting at a stop light and will make a vehicle feel as if it has a slight shimmy of sorts. One of the most common symptoms of a bad spark plug wire is a rough, irregular, or erratic idle. The following are several of the most common symptoms associated with a bad spark plug wire. Learning to recognize these symptoms can prove quite valuable when attempting to remedy the situation at hand, and return a vehicle to proper operating condition in an expedited fashion. The presence of one or more faulty spark plug wires is often accompanied by a host of secondary symptoms.

Systems of this nature do not feature a standard distributor or plug wires, instead opting for the use of individual, cylinder-specific coils, mounted directly to a spark plug via a unitized boot. Over the past couple of decades, many automakers have begun utilizing coil-on-plug arrangements, rather than traditional distributor-driven ignition systems. While this might seem somewhat contradictory, one needs to look no further than the modern coil-on-plug ignition systems found in many of today’s vehicles for further understanding. However, not all spark plugs require the use of spark plug wires. Do All Vehicles Have Spark Plug Wires?Īll gasoline-powered internal combustion engines rely upon spark as a source of ignition and feature head-mounted spark plugs. The resulting arc is therefore responsible for igniting the volatile air/fuel mixture found within each combustion chamber. This energy then dissipates, as it arcs between a spark plug’s central and side or ground electrodes. Power is discharged through each respective plug wire, before ultimately reaching a spark plug located at each wire’s terminating end. An engine’s distributor is timed to coincide with an engine’s firing order, thereby discharging inlet power via a specified connection point, which is fed by a revolving rotor button and a set of cylinder-specific contacts. Power delivered via an engine’s spark plug wires originates at the ignition coil, before being directed to the vehicle’s distributor cap. An engine featuring a standard distributor-driven ignition system utilizes one spark plug wire for each respective cylinder. Spark plug wires carry moderately high-voltage current from its point of introduction at an engine’s distributor cap, to its terminating destination, the spark plug. Should Spark Plugs Be Replaced At the Same Time?.Are “High Performance” Wires Worth the Money?.