Timing light - intermittent strobing

[Geekay]

Bought a new ToolPro timing light (see image) and it worked well the first two times (about 2 weeks ago). 251 6 cylinder motor on my 1954 Dodge.

Just wanting to check timing again and now the strobe light only flashes occasionaly for a few seconds, then nothing.

The digital read out is working so not a power problem.

I took the light back to Super Cheap Autos and they gave me a new one. Same situation.

I notice the pamphlet say it is recommended "for most negative earthed vehicles..".

My Suburban is Positively earthed. Will that make a difference?

Or, could there be another issue? e.g. coil? condensor?

The engine was running okay but now has a intermittent small backfire through exhaust. I am thinking timing but perhaps something else. It is set at about 1 degree After TDC.

Is a few degrees Before TDC better for these engines?

 

 

[mechresto]

Your '54 is 6v. Correct? Timing light is 12v. Use an aux. power source to feed the timing light only. A 12v battery hooked up negative ground to the light should work.

[Plymouthy Adams]

IF..you hooked the light up to the correct polarity regardless of chassis polarity, connect it correctly....if this is observed and still not strobing..try another plug wire..that one may be breaking down

[maok]

The magnetic pick up has an arrow, try pointing it the other way.

[Geekay]

4 hours ago, mechresto said:

Your '54 is 6v. Correct? Timing light is 12v. Use an aux. power source to feed the timing light only. A 12v battery hooked up negative ground to the light should work.

No it is 12V however using another power source is a good idea.