It does this by making an RF impedance mismatch between spark wire (antenna) and free air. I just wanted to get some numerical values in relation to the spark plug resistance comments. The thing these spark plugs had in common were that they were all Champion-brand plugs and they all measured very high resistance or even open-circuit when tested with an ohmmeter. Resistance is added to spark plug wires and spark plugs to greatly reduce RF radiated from spark plug wire. (free air has a RF impedance of 377 ohms). Spark plug wires normally last … Spark ignition is resistive sensitive. 95 nissan Altima. Also be sure you have the correct spark plugs installed. As far as there being more factors than the resistance, I agree. Resistance check shows value from 0.15 - 0.34 kOhm (1,500 - 3,400 ohm). A resistor spark plug will delay the time when the spark jumps. MSD’s 8.5mm Super Conductor Wire will measure about 50-ohms per foot of wire while the Street Fire brand wires have about 500 ohms per foot. To much resistance in the spark plug wires. We also saw a number of cases where high-resistance Champion plugs caused serious internal arc-over damage to Slick magnetos (mostly in Cirrus SR20s). Thinking of replacing spark plug wires (hadnt been done by me since getting the car in 2001). that would have shown as a very high resistance reading and not a low one like you found. Video tutorial on how to test a spark plug wires. You can also measure the resistance of each spark plug wire, but like coils, values may vary between wire brands. Start fresh with a new distributor cap, rotor and spark plug wires. Increasing Resistance : Perhaps the best way to tell if your spark plug wires need to be replaced is to test their resistance. Super Max II spark plug wires have two fiberglass braid layers and an intermediate silicone-EPDM layer for extra insulation, giving them a larger diameter. Voltage builds in a ramp regardless of how the spark is generated. Most wires should have 650-700 Ohms per Foot if they are in good condition. The basic function of a spark plug wire is to conduct spark energy from the ignition source, whether it be a distributor or coil pack, to the spark plugs. The new premium wires from Napa. High resistance in plug wires is generally caused by breaks in the conductor material of the wire and generally when that gap exceeds the gap of the plug then a misfire results. Getting too low with resistance is a problem because the wires are then … The more efficient the wire the more spark energy is transferred to the spark plug. The shortest ignition wire is only 2.85 kohm. Over time spark plug wires will wear out, causing various engine operation issues such as hard starting, misfires, rough idling, poor performance, poor fuel economy, and improper combustion burn. Hmmm, 5 wrong answers, until this post. Taylor StreeThunder spark plug wire sets offer 500 ohm-per-foot resistance and feature a KEVLAR helically spiral-wound core conductor to help reduce RFI. We didn't get into testing ignition coils yet, but that's my next step to see if there's a difference other than the harness plug and the spark plug wire connections. High Performance: High performance doesn’t always mean a long lifespan, and some types of high performing spark plug wires may need relatively frequent replacement (every 30,000 to 40,000 miles). Resistance is not the most important detail to be concerned with when choosing spark plug wires. 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