Ignition System Durability and Longevity Z24I

[Frankie Pintado]

I have an '87 D21 2wd with the z24i with a Weber 38 carb fitted to it. It has 84k miles.
So I just started having a type b misfire that I could feel at idle. It was not that bad yet, but it was getting slowly worse.
The entire ignition system was original up to today, including plugs. I replaced everything except the coils, but the crazy thing is that everything looked really good. I'm certain that I could have gotten away with replacing the 2 wires that come out of the coils and it would have worked perfectly again.

Since I'm a student in Auto Technology and this $250 truck is sort of my guinea pig, I tried running it on just the exhaust plugs, out of curiosity. I wanted to see if they would function as a redundant ignition system. Bingo.
It ran pretty well with considerably less power as the effect is like having your timing retarded too much. It could certainly be driven on the exhaust plugs if necessary. Of course, they both run off of the same triggering device (the LED in the distributor, the computer) so that part is not redundant.

I'm so impressed with this little engine.