What resistance should HT leads be?
The Society of Automotive Engineers suggests the maximum resistance should be 12,000 ohms-per-foot.
What is the resistance of a suppressed HT lead?
Some leads have a copper core with small resistance. Interference is suppressed by plug caps with 5,000 – 10,000 ohms resistance.
What do performance HT leads do?
Performance HT Leads are Worth it As soon as the flow is interrupted, the magnetic field collapses, creating or inducing a higher voltage in the secondary set. This is the current that then gets directed to the spark plugs. They are also known as high tension (HT) leads, the tension in this case referring to voltage.
Why do high tension leads have high resistance?
The high resistance reduces the radio interference from the spark this prevents it from interfering with radios and TVs. It also reduces the Electromagnetic interference, which in a modern car can play havoc with the electronic engine management system.
What causes weak spark?
If the spark is still weak after replacing the whole ignition system, then the normal size wiring or connector to the coil may be corroded or damaged somehow. The other real longshot is that the grounding strap between the engine/trans, body, and negative battery terminal is corroded/worn/damaged.
How many ohms should a spark plug have?
Serviceable Spark Plug Resistance To help assure reliable and trouble free operations, Tempest recommends replacing spark plugs in service having a resistance value of more than 5000 ohms (5k ohms) or less than 500 (0.5k ohms). For new plugs, we recommend 4000 ohms as the maximum acceptable value.
Why do ignition leads have resistance?
The resistance of many wires is measured in ohms per foot. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. That hotter spark can create a more even burn of the fuel/air mixture in the cylinder, and thus, more power output from the engine.
How do you test for lead resistance?
To check resistance of a standard lead using a multimeter, set the multimeter to the 20K Ohms (=20,000) range and measure the resistance of the cable (i.e. terminal to terminal). The result will be displayed in K Ohms, which means that the actual resistance of the cable is the figure displayed multiplied by 1,000.
How long do HT leads last?
The ignition cables on a car are made to last about 60,000 miles before they have to be replaced. In some cases, the wires will need to be replaced due to the rubber boots on the end getting damaged and now allowing for a good connection with the spark plugs.
