Help measuring resistance with multimeter to diagnose ignition

[frankd]

So I've got this old ATV (2000 Warrior) that started having issues starting. I thought it was fuel related but pretty much ruled that out so I'm going through all of the electrical components and trying to test them to see if they're within spec... but diagnosing electrical issues is not my strong suit and was hoping to get some help.

First of all, the service manual states to set the multimeter at 1k but my multimeter doesn't have a 1k setting. The available settings are 200, 2,000, 20,000, etc). So my first question is, if the manual says that resistance should be .8 ohms at a 1k setting, does that mean that at a 2k setting it should be double that? Or would it still be the same? I'm testing several of the components and nothin seems to be within spec so I'm clearly doing something wrong.

Also, the spark plug cap resistance is supposed to be 10k. When I connect it to the multimeter I'm getting a reading of 1 (regardless of what resistance setting I'm using). I used a continuity tester on the cap and there is no continuity. But the ATV is running and I am getting a spark (but possibly a weak one). I'm assuming there must be some sort of resistor inside the plug cap? perhaps the cap is the problem (or one of them).

 

[tdkkart]

Also, the spark plug cap resistance is supposed to be 10k. When I connect it to the multimeter I'm getting a reading of 1 (regardless of what resistance setting I'm using). I used a continuity tester on the cap and there is no continuity. But the ATV is running and I am getting a spark (but possibly a weak one). I'm assuming there must be some sort of resistor inside the plug cap? perhaps the cap is the problem (or one of them).

"1" is the same reading you get when you're not measuring anything, meaning there's no connection between the leads. So, assuming you're measuring the cap correctly, it's open, or no connection.
Most plug caps can be unscrewed from the plug wire, if you take it off the wire and look inside there will be a screw in the wire end. Put the meter on the 20K range, hold one lead on the screw, the other wire on the plug wire connection and you should get a reading. If you're still seeing a "1" the cap is bad, which would be part of your problem.

 

[Innovate1]

If it says use 1k use the 2k range as it's the closest one. No, you don't double the resistance based on the meter setting. I think the 0.8 on the 1k scale would be 800 ohms (0.8 k ohms).

 

[Mechtech]

The manual was probably written for the older analog meters, they had resistance ranged in 100,1k,and 10k (or similar depending on brand) the newer digital use a 2k or auto-ranged. The reading you're looking for depends on the exact wording, if it says reads .8 on 1k range (0 to 1 scale) your reading should be 800 ohms. If it says .8 ohms then it will be .8 (+/-) regardless of range. If you are reading 1 or open check your leads and meter battery first.

 

[frankd]

"1" is the same reading you get when you're not measuring anything, meaning there's no connection between the leads. So, assuming you're measuring the cap correctly, it's open, or no connection.
Most plug caps can be unscrewed from the plug wire, if you take it off the wire and look inside there will be a screw in the wire end. Put the meter on the 20K range, hold one lead on the screw, the other wire on the plug wire connection and you should get a reading. If you're still seeing a "1" the cap is bad, which would be part of your problem.

Thanks for the reply. My initial measurement of the plug cap is with the cap unscrewed from the wire. Still getting a 1 so I guess the cap is bad. I also put a continuity tester on each side of the cap and getting no continuity. The strange thing is that the spark is getting through the cap and the ATV does start...eventually but doesnt run well.

 

[frankd]

If it says use 1k use the 2k range as it's the closest one. No, you don't double the resistance based on the meter setting. I think the 0.8 on the 1k scale would be 800 ohms (0.8 k ohms).

Got it. Thanks!

 

[Sevenhills1952]

If you want to measure 8 ohms, 200 ohms scale is best for accuracy. You want lowest range for what you're measuring.
If spark plug cap resistance supposed to be 10K ohms, use the 20,000 (20K) scale.
If it measures infinity (no resistance) like when you hold leads apart...cap is bad. It may still run a bit because it's arcing across an open gap.

Sent from my SM-S205DL using Tapatalk

 

[frankd]

If you want to measure 8 ohms, 200 ohms scale is best for accuracy. You want lowest range for what you're measuring.
If spark plug cap resistance supposed to be 10K ohms, use the 20,000 (20K) scale.
If it measures infinity (no resistance) like when you hold leads apart...cap is bad. It may still run a bit because it's arcing across an open gap.

Sent from my SM-S205DL using Tapatalk

Thanks. I'm thinking there has to be some sort of disconnect in the spark plug cap. It's probably one of the cheapest things to change so I'll start there.

 

[Mike Folks]

Get a can of this,and do every electrical switch,lightbulb socket; www.caig.com pricey but a little goes a very long ways. I used in on my 1982 Kawasaki GPz1100 with fuel injection, never had any electrical problems.