My kids decided to make me something for Father's Day and found a link to a coil tester on the internet. They did a nice job making it but it does not seem to work right. When I hook it up to a battery the coil will buzz but I do not get a spark across the plug gap. Is it supposed to? I know this is not for tuning up a coil, just a basic test to see if the coil is working. But it is cool because they put it together.
Jim, Looks like your ground is going to the bottom of the coil, Isnt that where the Batt voltage is supposed to be? Might be just the limited wiring I can see in the pic but I think the top post should be from timer(ground), lower side post to plug, and Bottom of coil Batt power.
Kudos to the Kids, that is an absolutely awesome fathers day gift!!!
If it works or not, it/s a great gift from the kids !
Here is what to do. Remember that High Voltage will jump the shortest gap. Take the unit into a closet or wait till its good and dark and then test it again. Look very carefully and you will probably see a small spark somewhere along the black wire that is going to the plug. You really need that wire to be a spark plug type wire from a T or some other spark plug wire that has a solid conductor in it. I think what you might see is a tiny spark jumping from somewhere along that black wire to something metallic that is near it and that is where your spark energy is going. Are you sure this is a good coil? Swap that plug wire for the spark plug wire and move every other connection at least 3/8" away from any part of the ends of that spark plug wire. The kids are really going to have a good laugh on you if it turns out it has in fact found a bad coil in your pile ha ha. You can use even bare wire for spark plug wire but in those instances where you don't use spark plug wire you will need to make sure that absolutely nothing gets close to it from end to end.
I have to agree with John, he's the meister...but now I went and got myself confused because I always try and figure out electrical stuff, usually get it right on the 3rd or 4th time (Jim, don't pay attention to the following!)
Were I left to my own feeble brain with the same 'predicament', I would have daisy chained the top side post and the ground side of the spark plug then on to neg batt terminal...the bottom side post would be direct to spark plug top and then run the battery connection into the bottom post. (I'd also use a momentary push button on the 'hot' as point contacts can sizzle if left on DC too long? Or so I've been told) Am I missing something here? Maybe this is just reverse polarity to what my thoughts are and it doesn't care?
Not a trick or baiting question...just trying to learn here...maybe reduce my own 'oops' from 3-4 times to max of 2 when I have to
(John won't let me set a 3rd brush....lol...not with his VR anyway He has tried so hard to explain it, over and over, time and again with the patience of a saint and I'm stuck on permanent 'Brain F**t' on it...so it stays in a box for now )
The top side and bottom coil contacts are the coil "power" connections and the coil doesn't really care with is positive or which is negative. It will work either way. Likewise the spark output connection on the bottom side of the coil can be reference to either ground or power and the result will be the same though it typically is referenced to the ground connection.
Thank you very much John.