Duraspark ignition modules, those grey, aluminum boxes that manage the the signals from the electronic distributor to the coil, are so reliable that you never hear why or how they fail, or how you can tell if they are. Inside this grey, sealed box are nothing but circuit boards with a bunch of chips, a few resistors and timers. Well, my mover pal (owns a lot of Ford pickups and moving vans) gave me a couple of clues. One, they work until the engine compartment is hot and then they stop working (AKA engine stalls and won't start until the compartment is cooled down. Two, they switch on and off under load, like you'd feel if you were running on empty. Three, it just dies, the engine stalls and you're stuck somewhere between here and there. The rub is, that I can't find any testing procedures or even what you'd use to test it. Anyone got some suggestions?
I was told by a old ford tech to keep another module on board with me. So I have since 1995, kept a module and a cheep socket/wrench set with just in case. I have had a host of Fords and Lincolns from the 70s that used the same module. I have never had to use it....... All I have known, that these where bad from Ford. And when they got hot, they would quit. I'm sure you can test them but never knew of someone that could.
Well, I found this Duraspark ignition information resource discussing the 3 types of Duraspark ignition, to help guys who want to retrofit even older 289's, etc. upto 1974, when it first came out: http://www.mre-books.com/sa69/sa69_8.html The guy points out the following:
Duraspark failure and testing story Here's a published tale of one guy's symptoms, a temporary workaround to the parts shop and testing! http://www.nxtbook.com/nxtbooks/advanstar/ma0408/index.php?startid=13 He says that if he held the ignition key just past the run mode and before the starter kicks in, that he could run it. It gets better on the next pages. Good read.