Going to be used for car maintenance/restoration work and around the house repairs.
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1Very offtopic - suggest migration to electronics.se – Rory Alsop Aug 23 '11 at 11:17
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2I'm asking what multimeter features are relevant to auto maintenance... how is that offtopic at all? – Jeff Swensen Aug 23 '11 at 13:12
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Hmmm - I guess I see your point, however the whole point of a multimeter is it does everything the hobbyist should need. Will add an answer with some specifics. – Rory Alsop Aug 23 '11 at 14:26
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Ummm... Don't most multimeters do the same things? (Volts AC/DC, Amp, Ohm, Conductance, and sometimes Continuity). – Tester101 Aug 23 '11 at 16:26
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Digital automotive multimeter LCD automotive scanner EM133A. Not all multimeters are the same. I have three meters the one listed I use on my cars/engines. – spicetraders Nov 28 '16 at 3:17
Core functionality of a multimeter:
Measures Voltage - the majority will cope here, as you typically are only dealing with 0 - 12 volts across most areas. You aren't going to need it to measure high tension things such as spark plugs, as you can check them using far simpler methods (such as a spark from engine block to removed spark plug)
Measures Current - currents in automotive circuits and audio circuits can be very high (4 or 5 Amps in a headlight circuit, 100s of Amps to the starter), look for a multimeter with high current capability (2 to 10 Amps isn't too hard to find).
Measures Resistance - you'll probably find the most useful part of this is an audible continuity checker for checking cables deep in the bowels of your car
Frequency - less common on multimeters, but can be useful when working out speed/timing issues
Also make sure it is water resistant, and ideally comes in a rubber housing (as per @CodeBlend - Fluke are generally a robust and accurate brand to go for)
Anything more, and you're likely to need a computer with adapter and software to look at your ECU.
answered Aug 23 '11 at 14:32
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I like to have a digital and an analog on hand. Digital is more precise, but analog lets you see trends/changes better. – Brian Knoblauch Aug 23 '11 at 20:55
While I've got quite a bit of electronics and mains test gear, I just got what I missed for automotive use - a multimeter with a clip on DC amp function. On vehicles currents are often quite high and it's nearly always very difficult to insert a meter into wires. Fluke would be nice but are expensive, so I got a small Uni-T model. Seems to do the job.
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Many clamp on amp probes output either a scaled current or a voltage, and so can be used with any meter. I've gotten some very good deals on used Fluke meters on e-bay. – dlu Nov 28 '16 at 11:50
Ohm per volt rating the higher the better, Digital are minimum 1 M ohm per volt -Maximum 10 M ohm per volt. Analogs are in range of k ohm per volt- more loading of the circuit resulting in a lower than actual value. The frequency function probably would be worth not much as tach signal are pulses and would be read better with a scan tool. The frequency function might be good for audio or steady sine wave. AC and DC function for current and voltage. An Ampclamp (essentially a current transformer) would be on my wish list.
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Hmm, a current transformer type ampclamp will work with AC only. Since there's not much AC in a car, put a more expensive/complex DC ampclamp on your list ;-) – sweber Nov 28 '16 at 8:37
I know a couple of bits and pieces but not enough to recomend, here is a forum with some people that sound like they know thier stuf;
I hear Fluke meters are the business. But for 90% of people just go and drop $50 or something at a decent tool store.
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2Given the choice between a 5 year old fluke off eBay and a new cheap unbranded DMM with the same features, I would take the fluke every time. They stay in calibration for decades and can take some serious abuse. Few other DMMs will survive being thrown around a workshop as well as your average fluke. – Mark Booth Sep 7 '11 at 17:39
A couple of other features worth having are duty cycle measurement and a diode test function. The Fluke 87/88 meters have this and have been around long enough that you can often find good deals on them used.
