Truck is Smoking

[geezer101]

The ballast resistor. It boosts voltage to the ignition components from the distributor to the spark plugs. You will know when it has failed as the truck will inexplicably just stop after a while of driving it, then immediate attempts to restart the engine will fail. Wait for 10 minutes - and it starts fine. Then it's rinse and repeat. They will do that if the ceramic body of the resistor has cracked, causing the resistor winding inside of it to develop a single hot spot. Not so easy to diagnose unless you have experienced it before - if it fails, make sure you get a replacement unit with the same OHMS rating.

*when it does fail, the resistor will be hot - I mean, hot enough to automatically burn your fingers on contact. They do get hot during normal function but not enough to invite everyone over for a barbecue...)