Hey Guys,
Faced with a very intermittant no start that never lasts long enough for me to round up an assistant to check for spark (and some time off from work), I bought a cheap timing light and wired it up to work in the passenger compartment so I'm ready for the next time. Step one. Then I started thinking, why not have a permanant spark gauge? I've got the inductive sensor around a wire and then pretty securely wire tied to the valve cover gasket so it could be permanent. So if I disasemble the light and put the electronics in a small plastic box behind the center console I could put a small bulb of some sort in the one blank rocker switch panel. But what kind of bulb? I'm no electronics guru but I know some of you are. The light doesn't have any markings on it as far as current draw or wattage. So what kind of bulb should I use? Led? I want something not so bright as to be too much of an annoyance. I saw a post once on something like this but could not find it. Any advice appreciated and better a Radio Shack p/n would be great for non-electronics type like me.
Robb

I'm kind of reluctant to post this after Art's EE example, but it is simple...

The Farmall tractor guys are always chasing down problems. Jim Nicholson suggested a simple spark monitor using 15 turns of wire around the plug wire and a NE-2 bulb. http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=743319

What do you think Art ?

Greg

Hi Greg,

Yes, the neon bulb is better than what I did, because with it, you actually know something about the spark at high voltage, instead of just the primary at the tach. I have a pocket tester made of bakelite with an NE-2 (or maybe an NE-51) inside, but I found it to be kind of iffy around Volvo wires. Of course, it is probably 40 years old.

If anyone wants some NE-2 bulbs to play with, I have plenty. I pulled one out last summer to see if it worked as a spark indicator with just a few inches of extra lead (not 15 turns wrapped around the plug wire) and found it impossible to see in the daylight. Kinda gave up on it.
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Art Benstein near Baltimore

Be careful of your thoughts, they may become words at any moment.

Art,
Just wired this up per the tractor guys - about 20 loops around spark plug wire 4 and then ran that to a radio shack neon indicator light ($1.99) mounted in the last blank rocker switch panel. Picked up the ground on the back of the valve cover and ran that to rocker switch via a hanger snaked thru behind the center console. Works well - it's a little dim but you can see it in daylight which is all that matters. This is a nice addition to the gauges and will help me the next time I get that very intermittant no start. Thanks for the input all.
Robb

Hi Robb,

That sounds great. I'm a little fuzzy on how you snaked that wire inside, but I suppose there are many options. Once I tried to do it "right" by cutting a hole and using a grommet (for a much larger set of wires though) and neglected to seal it up once I was done with the diagnostics. Mama mouse nibbled the grommet and found warm refuge in the padding under the carpet. Once discovered, one of the babies was left behind long enough to allow me time to fetch the camera.



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Art Benstein near Baltimore

Duct tape is like 'The Force'. It has a light side and a dark side, and it holds the universe together.

Hi Robb,

Here's what I did to chase that suspicious EZ116-K ignition intermittent. The LED added to the tach looked out of the hole where the knob for setting the large clock used to be. It is a really simple mod if you can get someone with radio-shack type skills to fashion it. No wires through the firewall or anything.

The rather bright LED light did become annoying and didn't really help in my case. The intermittent was a marginal CPS I had installed proactively. You probably read about that in one of my older posts.


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Art Benstein near Baltimore

"While driving yesterday I saw a banana peel in the road and instinctively swerved to avoid it...thanks Mario Kart."

Sounds like an interesting idea to me. I would say you'll have to use a flash bulb or a small un-ballasted (I think) fluorescent light bulb. You can use the induction to make your own timing light. If you look up a link to home-made timing light, it should tell you how it works.
As for size.... you might want something really small physically. I'll have time to look, but my advice is sketchy today - I had anesthesia earlier.

Good Luck,
Will

PS howstuffworks.com might have some theory help.
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1990 740 Turbo, on its way to stock specs, maybe beyond