I have 2 plugs that get black and crusty fast. There IS spark going to them, but maybe not enough. What is the procedure to check the resistance of plug wires? If I can find that they are faulty I can get replacements and it will take a load off my mind. Thank you.

 

no one knows?

 

no one knows

 

no one knows

 

The most common way to check for resistance is to use an ohmmeter. Dital Multi-Meters(DMM) are generally the most accurate.

Remove both ends of a spark plug wire and connect one end to one of the ohmmeter's leads and the other end to the other test lead. Read resistance.

Resistance will vary depending upon wire type and length. Measure all of the leads and see if it's close to the other's.

I have a suspicion that if you had an ohmmeter (or DMM) you wouldn't be asking this question.

 

I have one but it's the first one I've ever had and I just didn't know the correct procedure to get a true reading. I actually have done what you have described and it reads zero every time. From the other readings people say they get, mine don't make sense. I put the dial on 20M (what ever that is) in the ohm section and with one test lead in the common jack and the other in the V,ohm,mA jack, I put a lead at each end of the plug wire. Am I missing something?

The only other jack has "10A" by it and the other sections of the dial are
V~
V-(with 3 dots under the slash)
mA
and finally hFE with PNP and NPN settings

 

Yes, the "20M" is the 20 meg-ohm reading, or the highest reading. You want to adjust the reading closest to the range that you are reading. The resistance selector is typically:

200 (ohm)
2K (2,000 ohm)
20K (20,000 ohm)
200K (200,000 ohm)
2M (2,000,000 ohm)
20M (20,000,000 ohm)

If you're reading something that is very low resistance, like a light bulb or a piece of wire, select the lowest (200 ohm). You'll probably get something close to zero (0) ohms for a wire, a little higher for a light bulb (measuring the filament).

The higher scales are for measuring things that have a higher resistance. You can measure the resistance of your skin between two points on your finger. Use the highest scale (20M) becuase there is a lot of resistance there. 3-12 meg-ohms is typical, and will be higher if you use points farther away because there'll be more resistance.

Measuring spark plug wires, use the lowest scale to get a reading. If you use too low a scale, you will get an "over-range" indication (if it's digital, or DMM). If it's analog (needle), it'll just read full scale. Use the lowest scale that gives a reading. 8-15K (8,000 - 15,000) will be typical, depending upon length and type of the wire, but could be as low as a few hundred ohms per foot, or even lower. Then you'd use the 2K or 20K scale.