Topic: No spark -- bad igniter?

[:)bestgen4runner]

Hook up your spark test setup.
Disconnect the igniter.
turn the key on. verify power to + side of coil.
Disconnect anything hooked to the negative side of the coil.
get a test lead. one end at battery ground the other loose.
with ignition turned on hold loose end of jumper wire to the negative side of the coil for a count of 2 then remove.
Report back if you see any level of spark.
Please make sure your spark test setup is quality and not just a spark plug hooked to the coil wire laying on the valve cover. a bad test setup will send us in the wrong direction.
 

[Snowtoy]

OK, it's a matter of perspective.

Actually, most winters in my part of the state get down to -20 at least once.

-20* and -30* temps are just as hard on vehicle components as extreme heat, both shorten life expectancy, and require more servicing than those in moderate climates.

[Gnarly4X]

-20* and -30* temps are just as hard on vehicle components as extreme heat, both shorten life expectancy, and require more servicing than those in moderate climates.

True...  Extreme cold temperatures can affect component material life, like failure caused by shearing or fracturing.

However, most of the conformance testing by the AEC and JDEC, for example, is done at high temperature. The reason is that the components and materials used in automobiles (rubber, polymers, cork, carbon fiber, etc)  are typically exposed to self-generated and normal operating heat, not cold.  The operating temperature ranges for materials, like rubber or the material used in an ignitor, has a closer high temperature limit to actual vehicle operating temperatures than the cold temperature limit.  In other words the typical engine bay temperatures have the highest potential to exceed component and material operating temperature ranges, thereby potentially shortening life, and causing a system failure.

Gnarls. 

[Lewis Hein [OP]]

Just thought I'd finish up the story. H8PVMNT kindly sent me an ignitor to test, and it did indeed solve the problem. (Thanks, by the way).

So ignitors do spontaneously go bad. And they can be replaced with a "new" one of a different year truck.