So 2,400-3,000 with my 2 foot wires. A shorter wire with a length of 12 inches may test out between 6.00 to 7.00 ohms and a longer wire of 30 inches may measure out between 9.00 and 11.00. However, some OEMs have recommended different maximum resistances. Many things effect spark plug gap settings. 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. also check the sparkplugs for a fouled out condition. You should get a reading between 11.3M (11,300) - 15.3M (15,300) Ω's. Types Of Spark Plug Wires The most popular aftermarket plug-wire construction for street vehicles — and even race cars — are spiral-wound wires. unplug the ignition wire connector from the coil. A quality spark tester, on the other hand, requires tens of thousands of volts to fire. To check, perform the following steps: Remove the spark plug wire from the engine. With the way the 031 is constructed the wire lead to the plug boot is short, and the cover/handle makes it rather challenging to get the plug to the cylinder for grounding while still being able to see the electrode & look for spark. 2) Spark plugs are very inexpensive to replace. I'm fairly certain there is no spark though. A narrower spark plug gap will help high rpm stability. I still have the '95 one here, as well as a spare newer coil pack. If the firing end of a spark plug is brown or light gray, the condition can be judged to be good and the spark plug is functioning optimally. This wire is about 2 feet long so we should be expecting about 1300 to 2500 ohms. Then multiply the Ohms per inch by 12 to get the Ohms per foot. References Take a better look at your meter, no offense intended. RPM: The higher the rpm's the less time the coil has to charge to break over voltage or complete saturation. It is for this reason that most racing plugs are non-resistor types. Its in the many-thousands of ohms. This, in turn, melts the coil’s wire insulation causing the wires to break requiring a new ignition coil. Spark plug wires have become nearly non-existent on many modern vehicles. Technician B says that a defective pickup coil wire can cause an engine miss. I wired in a newer (97, male coil) coil pack onto my car, a '95 that had a female coil stock. We are looking at 940 ohms. New Spark Plug Resistance. Combustion engines -- like the one in your lawn mower -- require a spark to ignite the fuel the engine needs for operation. 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 … Once a plug’s resistance gets higher than that, it’s time for a new plug. Spark plug wires deliver thousands of volts – up to 45.000V, depending on the application – to the spark plugs. Champion Spark Plug Company’s Engineering Manual gives the nominal value for their resistor type of aviation spark plugs as 1000 - 1500 ohms (no +/- value is shown, but minus 400 and plus 1000 probably wouldn’t be … Although there are many different cases, if the insulation resistance between the center electrode and the shell is over 10 ohms, the engine can be started normally. Generally they have positions for different levels of resistance, from 2 ohms to 200k ohms; choosing the right setting will give you a better idea of the right reading, which should be around 2000 ohms. A 24-inch wire may come in between 7.50 and 9.00 ohms. To check the resistance of the wires, use a multi-meter to test the resistance (Ohms) of the leads. Spray some water with a spray bottle as well around the wires to check for arching. So, although you may have spark, it may not be adequate to jump the plug gap with the engine running. 3) If you haven’t changed your spark plugs in 2 years or more, your problem could likely be a bad spark plug. Dry and Wet Fouling. 1-15 in.. 3000/10,000 ohms 15-25 in.. 4000/15,000 ohms 25-35 in.. 6000/20,000 ohms OVER 35 in.. 8000/25,000 ohms Also inspect insulation for any damage. The Society of Automotive Engineers suggests the maximum resistance should be 12,000 ohms-per-foot. Reasons to check your spark plug first: 1) A bad spark plug is the main cause of poor engine performance. Typical secondary coil resistance specifications usually range from _____ ohms. Here is a fast easy method to diagnose if your spark plug is the problem. Chainsaw, lawn mower or weedeater won't start or spark plug has no spark? While this is below the generic range, these are a higher quality wire so the resistance is less, so as mentioned before, check your vehicle’s specifications or the spark plug wire manufacturer specifications. If you have the high-resistance wires, there is a chance your simple tester might not register continuity. Consult a tune-up manual for exact specifications. Not hard to differentiate between the two. Either you will be at one extreme or the other. When to replace spark plug wires. Technician A says that a defective spark plug wire can cause an engine miss. Routine Maintenance: Re: Spark Plug Wire Resistance reading I don't know personally, but zero"ish" for stranded wire and 5k ohms"ish" for resistance wire, obviously length dependent. If we divide 2,000 by 2 — we get 1,000 ohms of resistance per foot. One last check should be to verify that the resistance of the plugs is below 5,000 Ohms. Testing spark plug wires and diagnosing bad spark plug wires. I have been looking everywhere and I keep getting different answers on the internet. 6,000 to 30,000. When removing spark plug wires, do not pull on the wire itself. Again this may vary by a little .. but not too far from that. All of the above readings would put you in a normal range. As an example, if you have 4-feet of Super Stock 5000 or Street Fire wire, you should have an ohm reading of 2,000 ohms. Replace any wires with resistance greater than 30,000 ohms which indicates that the internal conductor is failing. manufacturers' specifications). Important, yet un-sexy. Testing a spark plug wire’s ohm resistance with a multimeter is a good way to verify they are in working condition, and if the wires are capable of delivering the required voltage to the spark plug. Spark Plug Wires. Resistance values differ between manufacturers. 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