Is it just the age of the unit after some number of miles, or other reasons?

A friend of mine has a 98 civic that had this failed on him shortly after he changed the distributor cap and rotor...and he cranked the engine (without the cap on) to line up the screw that holds the rotor so he can access it.

He claims that he had done this same thing many times before and never had a problem...so is this what caused the failure of the ICM? He's got over 200k on his car, so not sure what really have caused it to fail...

Thanks...

 

If you bump up the gap the coil has to pump out more volts to jump the gap. Normally this can fail a coil internally (primary and secondary circuits melt together). As far as the icm i have never failed one testing the spark it probably has to do with age and maybe a shitty deigned.

The icm is just a switch that turn on and off the power to the coil. Switches fail over time and if thy are made with shity materials thy fail faster.

 

Yeah, cranking without the cap on will only damage the coil, not the ICM/Ignitor. From what I understand, it's fine to do that very short crank just to get access to the rotor screw while the cap is off. I've always done that myself, it shouldn't be able to overheat if you just do it one millisecond at a time (checking it's position after each, until it's lined up).

Might be smarter to return the cap first, or at least put a plug wire on the coil's winding terminal (such as if checking to see the rotor is turning).

Like Fuse said, most likely age, the other thing to look at would be the heat sink - if you replace the ignitor and reuse the old heat sink, you should apply new heat transfer goop (like what's used on a computer processor) or at least not wipe the old off before assembling them. Do that and it'll likely fail prematurely.