How to use a multi-meter
10-18-07, 11:25 PM
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How to use a multi-meter
I did a search but turned up nothing. Iam having electrical problems with my car so I went out and bought a multi-meter. Problem is I really dont understand how to use it. What setting should it be on and what should I be doing to track down my electrical gremlins? Thanks in advance
10-18-07, 11:44 PM
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^.^;; Yeah, I can't help you without what kind of multimeter it is and what your problem is. I'm taking an Auto electrics course so I could tell you how we use them in our class. XD
10-19-07, 01:38 AM
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The car died on my gf she had it towed home, everytime i tried staring it all i got was a click. I took my starter to autozone they tested it, they said it was bad so i replaced it. When i tried starting the car i got smoke from my altenator and my fusible links. I replaced the fuses and the altenator but I havent tried starting the car since i've been worried about frying it so I bought the multi-meter it a cheap one they carry at autozone.
10-19-07, 01:38 AM
#5
When you look at your digital multi meter (DMM), to check any kind of voltage all your voltage is direct current (DC) on the DMM they are usually represented by a dash, with 3 dots underneath it. Also make sure its the one that says (V) and not (A). The A checks for amperage. When you look at the numbers on there, it if it says for example 2, the maximum range for displaying on the voltmeter is 2 volts, but for most car applications you want it around the 20V setting. On most voltmeters about the positive and negative leads, if its digital multimeter, it won't matter how you connect it it would just show a negative sign infront of the number, you just have to remember to ignore that for most applications.
Now for checking for broken wires or loose connections, the setting you want to use is usually in either the ohm section (looks like a horse shoe) or just a section of its own. The symbol for that looks like either a circle with like 3 waves coming out of it or an arrow pointing to the right, with a line cossing perpendicular to that. Another way of testing that is touching the 2 leads together and you will usually hear a beeping noise.
Now if you're testing equipment as in the range its working at and they tell you it should work at this many ohms, or turns on and off at this many ohms, what you want is stay in that horse shoe area, What you normally want to do is start from bigger to smaller, to say you start at like 20M or 2M (varies for everymeter what its highest point is) and then go smaller, the smaller you go the more accurate of a reading you get so say you read like 2ohms in the 2M range, when you go smaller on the meter itself, you will start to see a decimal number associated with it, and find out it might really be like 1.876ohms on some application you need that accuracy on others you don't but its there.
For other things if you're checking voltage inside the house, that is AC voltage, so you will need to switch the meter to the one that says V with a sine wave beside it (its like a wiggly line)
And thats my course for today
Now for checking for broken wires or loose connections, the setting you want to use is usually in either the ohm section (looks like a horse shoe) or just a section of its own. The symbol for that looks like either a circle with like 3 waves coming out of it or an arrow pointing to the right, with a line cossing perpendicular to that. Another way of testing that is touching the 2 leads together and you will usually hear a beeping noise.
Now if you're testing equipment as in the range its working at and they tell you it should work at this many ohms, or turns on and off at this many ohms, what you want is stay in that horse shoe area, What you normally want to do is start from bigger to smaller, to say you start at like 20M or 2M (varies for everymeter what its highest point is) and then go smaller, the smaller you go the more accurate of a reading you get so say you read like 2ohms in the 2M range, when you go smaller on the meter itself, you will start to see a decimal number associated with it, and find out it might really be like 1.876ohms on some application you need that accuracy on others you don't but its there.
For other things if you're checking voltage inside the house, that is AC voltage, so you will need to switch the meter to the one that says V with a sine wave beside it (its like a wiggly line)
And thats my course for today
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10-19-07, 11:08 AM
#9
The car died on my gf she had it towed home, everytime i tried staring it all i got was a click. I took my starter to autozone they tested it, they said it was bad so i replaced it. When i tried starting the car i got smoke from my altenator and my fusible links. I replaced the fuses and the altenator but I havent tried starting the car since i've been worried about frying it so I bought the multi-meter it a cheap one they carry at autozone.
This "Smoke". Did this happen after you installed the starter?
10-19-07, 11:13 AM
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Yea i installed the starter and when i tried cranking it POFF! my alt and my fusible links smoked. I read the wiring diagram for the 79 and I re-did my wiring per factory specs. I replaced my fusible links with box style fuses. Iam trying to get my hands on an electronic dizzy I discovered the previous owner installed a points style dizzy in the 13b. Thanks
10-19-07, 11:18 AM
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Yea i installed the starter and when i tried cranking it POFF! my alt and my fusible links smoked. I read the wiring diagram for the 79 and I re-did my wiring per factory specs. I replaced my fusible links with box style fuses. Iam trying to get my hands on an electronic dizzy I discovered the previous owner installed a points style dizzy in the 13b. Thanks
There's no way in hell you're getting a brand new distributor. Even if it is new in box, how would you know if it wasn't defective from the factory...
The worst thing ever is trying to track down more than one problem...
As far as smoke from the alt and fusible links... You took the battery out when you replaced the starter, right? Look at the connections again. Sure that battery is in properly? That's the most common cause.
10-19-07, 11:39 AM
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Now for checking for broken wires or loose connections, the setting you want to use is usually in either the ohm section (looks like a horse shoe) or just a section of its own. The symbol for that looks like either a circle with like 3 waves coming out of it or an arrow pointing to the right, with a line cossing perpendicular to that. Another way of testing that is touching the 2 leads together and you will usually hear a beeping noise.
10-19-07, 05:23 PM
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10-19-07, 05:31 PM
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Yeah I disconnected the battery when I replaced the starter at one point I said **** it went to sears bought a new battery and ordered new battery cables hook them up and still no dice. I hate electrical problems!
10-19-07, 05:38 PM
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its one of three things, the battery is backwards, the starter is wired wrong, or the charge wire going to the alt is shorting to ground. to check for short to ground put the dmm on continuity check or ohms. touch one lead to the charge post on the back of the alt, that will be the big single wire. the other lead to chassis ground. if it beeps or you have 0-15 ohms of resistance you have a problem. since the charge wire goes to the +side of the battery dissconect the charge wire from the alt and recheck for ohms or beep.if it beeps the problem is not with the alt.remove the positive wire at the starter and recheck. if it beeps the problem is not with the starter.which means you have a short to ground somewhere in the wiring harness. check for bare wire or wires touching bare metal.
10-19-07, 05:42 PM
#19
Yankle My Wankel
I'd suggest learning a little more about electrical troubleshooting before you get elbows deep in this, becuase by the looks of it, you don't even know what an ohm is, or what an amp is. But judging by the looks of your problems, you have a shorted starter curcuit, and when all that magic smoke came out, your fired alot more than just your starter. Take it to a mechanic and get it done right, unless your hell bent on doing it yourself. Then get reading up on automotive electrical on the internet.
10-19-07, 06:31 PM
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I hear you Iam not going to lie I haven't really dealt with automotive electrical, but I refuse to take the car to a mechanic. The last "rotary mechanic" that worked on my car dissapeared with my cash and stripped my car. Never again will I fork over cash or my car to anybody. Iam going to re-check everything I will let you guys know what I come across.
10-25-07, 06:53 PM
#24
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you get it from somewhere or just something you came up with?
