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DoubleVision 03-01-2012 05:26 PM

Plug Wire resistance.
 
I was just checking my MSD Super Conductor 8.5mm wires. Had these since about 2006 but they only have 30,000 miles on them.
To get the reading I have to put the ohms on 200K which is 200,000.
My meter says the wire is 115.2 and I'm thinking either I'm reading it wrong or this can't be right, if the resistance on the wire is that high I can't see how it ran at all, whats going on here? MSD says the resistance of these wires is about 50 ohms a foot, so am I doing something wrong here or is there another way to test it?

LATECH 03-01-2012 06:44 PM

Quote:

Originally Posted by DoubleVision
I was just checking my MSD Super Conductor 8.5mm wires. Had these since about 2006 but they only have 30,000 miles on them.
To get the reading I have to put the ohms on 200K which is 200,000.
My meter says the wire is 115.2 and I'm thinking either I'm reading it wrong or this can't be right, if the resistance on the wire is that high I can't see how it ran at all, whats going on here? MSD says the resistance of these wires is about 50 ohms a foot, so am I doing something wrong here or is there another way to test it?

Nothing wrong at all. You could use a lower scale on the ohmeter, but it isnt that critical.
If you use a 1000 ohm scale, the wire would still read 115.2 or close to it.
115.2 Ohms is probably correct. 50 ohms per foot means the wire must be about 2 foot 3 inches long.
using a different scale is like changing the scale on a gauge.you wouldnt use a 0-1000 pound gauge to check the fuel pressure on a carbed engine that runs 7 pounds,it would be hard to get definative results.you would use a smaller scale gauge, say one with a 20-25 psi range.Making it easy to measure small differences in the actual value.Using a scale closer to the value you are looking to measure ensures a better accuracy of measurment.
I think your just confused about the scale thing,confusing the reading you are getting.

DoubleVision 03-01-2012 06:57 PM

Thanks Tech, however, if I place it on a lower scale I get no reading. I rolled the dial and tried them all and the only ones I get a reading on is 200,000 ohms and higher. I have another set of plug wires that I tested as well, they are moroso Blue Max wires, 800 ohms per foot, and they read lower on the scale, I get a reading with them with it set on 20,000 ohms.

LATECH 03-01-2012 07:03 PM

??? what brand is the meter. Are the batteries in it any good?? Sounds like the meter or batteries arent quite cutting it.

DoubleVision 03-01-2012 08:20 PM

It's a Etek model 10709 fully digital. The batterys are fresh, Just installed them last week. However I have another meter Identical to it that I keep out in the shed. I just went and got it and I'm gonna test the wires with it to see what reading I get.

DoubleVision 03-01-2012 08:27 PM

Okay just finished rechecking. With my other unit they tested 101.4 ohms, this was with ohms set on 200. Something is obviously wrong with my other tester so I'll mark it and only keep it around in the house as a battery tester. My good one I'll leave in the shed as my automotive tester.

LATECH 03-02-2012 05:11 PM

Cool Beans.. :thumbup:

1971BB427 03-02-2012 05:25 PM

Always check your meter for zero before you start testing anything. Need to set it on x1 setting and hold the leads together. If it is more than .3 to .5 ohms it's got a problem with the leads. If the leads are going bad, then don't use it for batteries either, or you'll get low readings there too.

F-BIRD'88 03-02-2012 05:40 PM

The scale selector switch contacts on your DVM probabily need to be cleaned.
Use old school rotary TV tuner contact cleaner or Electric contact cleaner (LPS)
and replace the battery.

These switch contacts corrode over time.


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