Spark tester can LIE

[Jim48328]

Just had a 12v conversion that wouldn't run. Did normal checks and used the plug tester that looks like a plug but has a ring around it at least 1/4 inch from the electrode. had a nice blue spark. Went thru the fuel system and it was Aok. Everything checked good but wouldn't even hit at all. Finally jumped the resistor and boom OFF and running. So the tester if your on the borderline of max resistance can fool ya.

 

[Jim L WA]

Interesting. I don't know what spark tester you have, but most of the recommendations on here call for an adjustable spark tester. Did you use a 12 volt coil that required a resister?

 

[Hobo,NC]

Lets see yer tester... Did it pop the tester continuously are was it a hit and miss deal..

 

[sotxbill]

spark tester shows jumping gap at NO pressure or compression. A spark plug tester shows the plug sparking at no pressure, then you turn the pressure up till the plug fails,, to test it. All plugs will fail, if you turn up the pressure high enough on a standard coil/plug tester.

High energy ignitions fix this problem so that marginal plugs are NO longer marginal and will fire through out the 100,000 mile service life.

Standard coil ignition systems however must be perfect... perfect resistor, perfect coil, perfect rotor, perfect wires, perfect points, and perfect plugs. Bypassing the resistor, just turned up the voltage so it would fire past the defect. Question is... what is the defect or multiple defects????