Spark tester

[ndutton]

I bought a new gadget. It's a non-invasive spark tester, simply lay the end on a spark plug wire and a light in the shank flashes with every current surge (spark). It indicates the complete ignition function from source to plug, one plug at a time if you like or all of them by sensing the center coil wire. If there's no spark at the plug, no current flows and therefore no indicating light illuminates. You don't need to disconnect anything.

It's a yes or no tester, does not indicate spark quality. For quick troubleshooting it's pretty cool. They can be had at a variety of places, Home Depot online included for around $8. I got mine on ebay for $3.75

https://www.ebay.com/itm/Auto-Car-Test-tester-Ignition-Spark-Indicator-Plugs-Wires-Coils-Diagnostic-Tool/291943385900?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

[goodoldboat]

tester

very nice gadget ... I wish I had one last week ..

im getting one thanks for finding it .

[romantic comedy]

How does it work?

I use one of those inline spark testers. But mostly I use insulated pliers or a rag to hold the wire then crank away.

[ndutton]

How does it work?

Without specific knowledge, I suspect it picks up the Gauss field produced when current runs through the wire.

[edwardc]

Back in the day, before LEDs (I'm showing my age), when working on cars we used to tape a small neon bulb to the end of a wooden dowel and hold it up against each wire. The strong electromagnetic field would ionize the neon and make it glow orange every time the plug fired. Looks like they've packaged this idea up into nice product.

[thatch]

Thank's Neil, I'm now $3.75 lighter.
Tom

[ndutton]

Anything I can do to lighten the wallet . . . .

Ed, from its appearance I'm certain the indicator lamp is neon. Old School Rules!!

[joe_db]

Maybe I'll just wire-tie 4 of those things on my wires
Disco Engine Room at night

[tac]

As Ed says, most likely neon or other gas tube:

https://en.wikipedia.org/wiki/Neon_lighting?wprov=sfti1

For those not theory-phobic, it’s probably Townsend Discharge, an electric field phenomena, not magnetic field:

https://en.wikipedia.org/wiki/Townsend_discharge?wprov=sfti1

One problem with these cheap tubes is that over time the gas leaks out through the glass envelope, and the glow slowly fades out.