I think that if you run the engine with the cowling cover off, (the inside cover behind the glovebox), I think that you will see sparks jumping to ground on the ignition coil. Astro's have tremendously high voltage spark plug voltage. If this voltage can find a path to ground, it will. You will hear a snapping noise with the cowling cover off if the coil voltage is shorting to ground instead of going to the spark plugs.
I will tell you a short story. I parked my Astro on a freezing night and in the morning it was 60 degrees and raining. All of that warm, moist air came across the Astro and moisture condensed on everything. I opened the door in the morning and the dashboard was wet. The van would not start. It would not even cough on starting fluid. I pulled the cowling and the distributor cap had a puddle of water on it. I dried the distributor cap with a paper towel. I tried to start it and it was at least coffing, but then I dried the ignition coil with a paper towel and it started and ran fine. I will never trust an Astro ignition system once it has found a path to ground one time. I got home and the holidays hit and I wasn't driving it. It happened again. A freezing night followed by warm rain. It coffed and started that time, but never ran right. If this ignition system grounds out, I always replace the ignition coil, spark plug wires, spark plugs (Autolite Double Platinum), distributor cap and rotor. Do not buy cheap brand ignition coil, spark plug wires, or cap and rotor. Do not buy Duralast or Valuecraft. Get the more expensive name brand stuff like Borg Warner, TRW, Sorensen.
I hope this helps you, but I think if you run the engine with the cowling off, you will hear a snapping sound like someone snapping their fingers with your spark plug voltage jumping to ground. The coil wire wants to rest against an engine crossmember which is grounded. I go to an electronic supply store and I wrap the new coil wire with 3/8 inch plastic spiral band and put 1/2 inch plastic split loom over that. Any electronic supply will know what these are and they are only about $4 and they sell it by the foot.
Thursday, January 15th, 2009 AT 7:52 PM