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

"Michael" <m...@gmail.com> wrote in message 
news:2...@v15g2000prn.googlegroups.com...
> 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 

On Oct 28, 2:39=A0am, "Tom Biasi" <tombi...@optonline.net> wrote:
> "Michael" <mrdarr...@gmail.com> wrote in message
>
> news:2...@v15g2000prn.googlegroups.com...
>
> > 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 bloc=
k
> 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


~11 year old truck.

Safe to just hold the wire?  Tens of kV arcing through the insulation
won't shock you?

Michael

On Oct 28, 5:49=A0am, N0S...@daqarta.com (Bob Masta) wrote:
> On Tue, 27 Oct 2009 21:45:34 -0700 (PDT), Michael
>
> <mrdarr...@gmail.com> wrote:
> >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?
>
> 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. =A0Not convenient. I
> know, but I couldn't get decent results with even
> much larger coils that were simply held near the
> wire.


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:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3D95652

Thanks,

Michael

>
> 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. =A0Should 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. =A0They
> suggested 470 ohms, but I've had good results with
> 10K. =A0You 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. =A0It actually
> measures period and inverts, so you get immediate
> high-resolution results. =A0
>
> 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. =A0It's got a
> free 30-session/30-day trial, which should be more
> than enough to test your vehicle. =A0<g>
>
> Let me know if there are any questions on how to
> use the software. =A0(There's over 500 pages of
> built-in Help, but it might be intimidating when
> you are just getting started.)
>
> Best regards,
>
> Bob Masta
>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 DAQARTA =A0v4.51
> =A0 =A0Data AcQuisition And Real-Time Analysis
> =A0 =A0 =A0 =A0 =A0 =A0 =A0www.daqarta.com
> Scope, Spectrum, Spectrogram, Sound Level Meter
> =A0 =A0 =A0 =A0 =A0 =A0FREE Signal Generator
> =A0 =A0 =A0 =A0 Science with your sound card!

On Tue, 27 Oct 2009 21:45:34 -0700 (PDT), Michael
<m...@gmail.com> wrote:

>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?
>

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.  <g>

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
             www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
           FREE Signal Generator
        Science with your sound card!

On Tue, 27 Oct 2009 21:45:34 -0700, Michael wrote:

> 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?
> 
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

On Wed, 28 Oct 2009 06:17:33 -0700, Michael wrote:
> On Oct 28, 2:39 am, "Tom Biasi" <tombi...@optonline.net> wrote:
>> "Michael" <mrdarr...@gmail.com> wrote in message

>> Since you said "distributor" I guess its not a modern vehicle.
> 
> ~11 year old truck.
> 
> Safe to just hold the wire? 

Yes.

> Tens of kV arcing through the insulation
> won't shock you?

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:
http://www.eclipsetools.com/ProductPics/Latest .jpegs/900-177.JPG

Have Fun!
Rich

Michael wrote:
> 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

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

On Wed, 28 Oct 2009 09:10:36 -0700, Rich Grise
<r...@example.net> wrote:

>On Wed, 28 Oct 2009 06:17:33 -0700, Michael wrote:
>> On Oct 28, 2:39 am, "Tom Biasi" <tombi...@optonline.net> wrote:
>>> "Michael" <mrdarr...@gmail.com> wrote in message
>
>>> Since you said "distributor" I guess its not a modern vehicle.
>> 
>> ~11 year old truck.
>> 
>> Safe to just hold the wire? 
>
>Yes.
>
>> Tens of kV arcing through the insulation
>> won't shock you?
>
>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:
>http://www.eclipsetools.com/ProductPics/Latest .jpegs/900-177.JPG
>
>Have Fun!
>Rich

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
             www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
           FREE Signal Generator
        Science with your sound card!

On Wed, 28 Oct 2009 06:21:54 -0700 (PDT), Michael
<m...@gmail.com> wrote:

>On Oct 28, 5:49=A0am, N0S...@daqarta.com (Bob Masta) wrote:
>> On Tue, 27 Oct 2009 21:45:34 -0700 (PDT), Michael
>>
>> <mrdarr...@gmail.com> wrote:
>> >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?
>>
>> 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. =A0Not convenient. I
>> know, but I couldn't get decent results with even
>> much larger coils that were simply held near the
>> wire.
>
>
>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:
>
>http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3D95652
>

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
             www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
           FREE Signal Generator
        Science with your sound card!