Ignition Coil Test (The Short Version)

welcome folks what I have for you today is a short video a very short video on how to test an ignition coil this type of coil here is say an oiled filled ignition coil probably used up until well gentlemen general motors usually use them up until about 1974 and then starting about 1975 they went into the HEI or high-energy ignition system but here's the old old type of coil it could either be triggered with the old ignition points or the transistorized type of advanced ignition control on this that did away with the ignition points so I'm just gonna give you a quick look at it what I've done on top here is I've put some plus and minus indicators here just cut them out of some masking tape just so the video would show it and it's only really important that you hook it up when you wire it into your actual vehicle as for testing these things it doesn't matter which way you unhook up your old meter the red and black lead set is okay so I'm gonna set this thing in a in a vise or to steady it out this is basically what it looks like that's the shape of the thing probably familiar with it if you've worked on the older cars like I say up till about 1974 general ballpark kind of a year and so here we go it's gonna be a short one so I try to orient this right and lock it in the vise so that the coil doesn't decide to take off on us here alright so there's two basic readings that we're after there's gonna be a low ohms reading between these two terminals here that's for your primary coil there's actually two coils that are contained within this canister here and on the the the high side or the secondary side you can go between either terminal on the primary that used for the primary and on to the secondary tower either like that or like this it's not really too fussy but if you really want to pay attention to the polarity read in North America basically means plus and the black is usually minus just in common terms but always check your specifications so here we go I'll turn the meter on and it's very important on the low range not the low range on the meter rather but to calibrate your your multimeter your own meter on the low range because if you're you're out a little bit it can actually show that you're out of specifications for your particular coil so it won't matter on the high reading because you're in thousands of ohms but on the primary side always check your own meter and make sure and calibrate it if it's Kelly you've got a adjustment on it this one this particular one does not have an adjustment so I'll have to do some simple mathematics okay I did check this without the wires and it's the meter that's actually out okay if you have long thin wires that can lead to more resistance okay so he calibrate the meters we're gonna have to subtract 0.3 of an ohm from the reading we're getting yet just on the low side like I say on the secondary or high side you don't have to worry about that small small amount of differential there so we'll go ahead and subtract 0.3 from our reading that we get here so make sure there's no oil on your terminals and also when you test these things don't have any other wires hooked up pretty much have it looking like you have here with no wires on the primary side or anything on the secondary tower so now um on the primary side we're showing a reading of 1.8 ohms now remember we have to subtract decimal 3 ohms because of that this calibration of this meter so 1.8 minus 0.3 is 1.5 1.5 ohms now I've off to the side here I've jotted down on a piece of paper some average kind of readings that they should get for specifications remember always look up the specifications for the coil that you're testing that you have on hand don't go by these figures at all but these are general ballpark ones if you don't find any other specifications for your coil so according to this the primary on this type of coil should be somewhere between 1.4 to 1.8 ohms so now we're getting 1.8 - the 0.3 so or 1 point 5 ohms we fall right in between the 1 point 4 and the 1 point 8 ohms that's on this piece of paper off to the side here so as far as ohms readings go this coil checks out on the primary side okay now to do the secondary side these particular probes here that you can unscrew the alligator clips okay they're little teeth things there grab so you've got your hands-free and we'll just probe the inside it up and remember we're gonna be going up into oh this one calls anywhere between 8,000 to 12,000 ohms okay so we're gonna have to bump this thing up a couple of ranges that other the first range on the primary only went up to 200 ohms so we need to get something that goes up to approximately 20 K or 20,000 ohms so we'll scratch this in here and see if we get a reading okay got to make sure that you really grind these things in there because if you don't have a good connection like you're going through oxidized metal it'll give you a false reading so always make sure you're grinding your connections and there's no oil on those connections otherwise you're gonna get a false reading make sure that the numbers are steady and not jumping all over the place so we got 10.35 and on the twenty twenty k range or twenty thousand ohms range that's on the meter that's basically ten thousand ohms and three hundred and fifty or ten thousand three hundred and fifty ohms so that falls well between the 8,000 to 12,000 homes that I was telling you about so the secondary side checks out and just quickly I can show you that it does the same thing also with the other polarity here they're interconnected inside the coil and they share a common connection point I would assume I've never opened one of these things up so I can't really guarantee that but you can see there are the the readout is pretty much the same and just quickly I'll just reattach this some alligator clip and we'll reverse polarity on here and take her down to the 200 ohms again and we should get that same 1.8 now it's my sometimes it moves a little bit I don't know whether is a the meter or something to do with whatever is going on but it's usually pretty close so you grind them in there make sure last time it showed 1.8 so in 1.9 there it's going back to the 1.8 now so minus that point 3 on the low side only see it's dancing between the two a can't make its mind up we're still at 1 point 5 ohms on the low side and like us mentioning before 1.4 to 1.8 ohms is good for the primary side where these do terminals here okay so and enclosing now that I've shown you how to show test rather the the two different circuits and here's two separate coils and they do share a same connection point in there somewhere I'm sure just in closing I'll mention a few things this particular one was taken out of service because this is a horizontal mount or it was mounted sideways on the intake manifold of Avedon v8 engine and there was oil that's contained within this coil leaking out of there and I didn't know how much leaked out probably not much but I took it out of service to make sure it wasn't gonna overheat and maybe cook those coils and caused the coil to malfunction or quit on me while in the middle of nowhere driving down some road okay so um that was one problem another one thing that I'd like to mention is to keep all your connections clean oil free if you live in a climate where it's damp and it rains a lot you want to be you know cleaning up your connections because they do oxidize they rust they corrode they do all kinds of things so 100% clean and shiny connections are the best no matter what the electrical component you're talking about in your vehicle so keep an eye out for those kind of things so there you have it folks there's the quick version for the sick dition coil with a few little tidbits thrown in for good measure I hope you enjoyed it that said and done be safe take care and have a nice day and bye for now

Channel: RockysRoadshow

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Keywords: Ignition Coil, Ignition Coil Test, Ignition Coil Testing, Ignition, Coil, Test, Tests, Testing, Ignition Coil Tests, Ohm, Ohms, Ohm Meter, Multimeter, Resistor, Resistance, Read, Reads, Reading, Readings, Spark, Sparks, Spark Plug, Spark Plugs, Volt, Volts, Voltage, Coils, Spark Plug Wire, Spark Plug Wires, Spark Plug Lead, Spark Plug Leads, Ignition System, MSD, Accel, Pertronics, AC Delco, Delco, Mopar, Mallory, Prestolite, Crane, Interstate, Battery, Ignition Reserve, Ballast Resistor, Lucas

Id: FIx4dxew_UU

Length: 8min 13sec (493 seconds)

Published: Thu Feb 13 2014