To test a non-starting vehicle's distributor, I need an inductive ignition tester to see if the central high voltage wire is getting juice.
Can I whip one up with a simple coil of electromagnet wire (~50 turns), connect to a DMM and place the coil near the HV wire?
Thanks,
Michael
In the old days we would just hold the wire a little from the engine block and crank. A spark would jump if it was working. With modern vehicle I wouldn't do this. Since you said "distributor" I guess its not a modern vehicle.
Tom
k
~11 year old truck.
Safe to just hold the wire? Tens of kV arcing through the insulation won't shock you?
Michael
What's the typical current going through a spark plug? Is it in the milliamp or microamp range?
I'm wondering if this could work:
Thanks,
Michael
The spark produces a very narrow spike, so I'm not sure that a DMM would show it (though I haven't tried this).
However, if you have a scope you can get away with far less than 50 turns (say, 8-10) wrapped directly around the coil wire. Not convenient. I know, but I couldn't get decent results with even much larger coils that were simply held near the wire.
Despite that, I found that I did need to keep the wrapped wire separate from the others to prevent it seeing spikes from other wires. Should be no trouble with the coil wire, though... I was trying to read one wire out of 4 in a loom.
In an earlier exchange on this topic, where someone wanted to use a frequency counter to measure RPM, it was suggested to use a small series resistor leading to parallel reversed diodes to limit spikes to +/-0.6 V or so. They suggested 470 ohms, but I've had good results with
10K. You can use LEDs instead of conventional diodes to get a bigger signal.I've been experimenting with this because the next version of my Daqarta software will include an RPM mode for the frequency counter, that allows it to correct for number of cylinders. It actually measures period and inverts, so you get immediate high-resolution results.
That version (v5.00) won't be out for a couple of weeks, but if you just want to monitor the spark signal you can use the current v4.51. It's got a free 30-session/30-day trial, which should be more than enough to test your vehicle.
Let me know if there are any questions on how to use the software. (There's over 500 pages of built-in Help, but it might be intimidating when you are just getting started.)
Best regards,
Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis
Pull the coil wire off the distributor. Hold the metal contact of the coil wire about 1/2" from the engine block/manifold/whatever, as long as it's metal and grounded. Crank the engine. If you get an arc, it's OK, check the cap/rotor/plugs. If not, then it's the coil/points/ballast/ condenser.
Hope This Helps! Rich
Yes.
No - that's what the insulation is for. If the voltage gets high enough to punch through that insulation, it will already have made the arc to the block. If it doesn't arc, it's because there isn't enough voltage, therefore not enough to do harm.
And even if you _did_ get zapped, it's WELL below 15 mA, and will give you a jolt, but non-lethal unless you have a pacemaker or some other preexisting condition.
Or, you could get a plastic fuse puller and hold the wire with it:
Have Fun! Rich
If you just want yes/no you could test by getting an NE2 neon bulb, splay the leads out, hold one lead and let the other one rub along the insulation of the still plugged in HV leads
Holding the wire with your bare hand can give you a kick! Been there, done that, lesson learned at a tender age. With 50,000+ V, especially on old wires, there will probably always be enough leakage to give you a poke. I don't think this necessarily leaky insulation, more likely conduction along the surface grime and humidity. May not harm you electrically, but when you jump you may hit something! You definitely won't try this twice.
Best regards,
Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis
When I go to that link, I get:
"The Specifications for this item are not currently available online, or the item has been discontinued"
So I don't think it will work, whatever it is!
Best regards,
Bob Masta DAQARTA v4.51 Data AcQuisition And Real-Time Analysis
It was there yesterday. that link was for a sale, and the last five digits are the stock number. It is a simple clamp on AC ammeter
Here is a link to the user manual.
It isn't designed to read low current pulses. it is for troubleshooting electrical problems and the lowest AC current range is
200 amps, with a resolution of .1 amp.That PDF also covers model 42396, which the 95652 replaced.
-- The movie \'Deliverance\' isn\'t a documentary!
Just spend a few dollars and buy the right damn tool:
$6.99 Lisle Spark Indicator SKU Number: 1JA 508138
Manufacturer's part Number: 19380
-- The movie \'Deliverance\' isn\'t a documentary!
Or a spare spark plug, firmly taped to metal on the block. Cant hurt
*any* ignition system to discharge through an appropriately gapped plug.-- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:
If that turns your crank. I prefer to buy or build real tools. An exposed plug could ignite fuel vapors but it's your face that will suffer, not mine.
-- The movie \'Deliverance\' isn\'t a documentary!
-- Definitely not a good idea, since if the reason the thing isn\'t working right is because of cracked insulation... Here\'s using an NE-2 for that purpose in a better way: news:mjftf5dd4m6bb2k2b1oue5mdh7rd6akklt@4ax.com JF
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