Hi, I have a 1971 Fury Custom suburban with a 318 2bbl, automatic. It was an early 71, so it still has the points-style ignition system. I was driving to work the other day, right as i let off of the gas to coast into the parking lot, it died, as it does sometimes, if it is not all-the-way warm, it chokes. Now, it is about 45 degrees out, rained all night and is just barely misting, plus fog. I do know that old mopars had a wonderful habit of dying in wet weather, so i waited until after work to mess with it... This is what i have diagnosed so far: -got fuel, and won't run on ether, so no spark, i conclude... -i have heard ballasts go bad frequently, so I tested it and it works, but i replaced it anyway just to be sure. -Now i have power to resistor and slightly less to + on the coil, as it should... -nothing coming out of coil -, so i replaced the points and condensor -clean vacuum advance plate, making good ground, and i even replaced the lead from coil to points. -now i have power to points, they are gapped, and my test light blinks when on coil - when i crank, but i have no spark at the points. -thinking it might be the ignition switch shorting on cranking, i ran a jumper wire from + on battery to + on coil, and it still won't start - i have continuity of the rotor and the cap (center nipple) and a good ground of the distributor. i tested instead of replacing cap and rotor as i replaced these components not even 2000m ago. - now all of this together, all components independently are good, i have power to all components, all lead wires and spark plug wires have continuity, and even if i bypass wires with a jumper, i still don't have spark at the points... AND i used a blow dryer on all ignition components to make sure they were very dry before i put it all back together... FML HEL
rotor turns, and appears to be lined up with TDC, rotor fits tightly, cap is in great shape, as i said it has continuity from the inside teet to the coil nipple, and i have jumped power to the coil, and i still don't have spark at the points
Make sure your wire coming from the dizzy is not shorting out on the vacuum plate or under the plate . I had that happen once . I would still try you old condenser to eliminate that . I had many NEW condensers that didn't work either . Also check the inside of the dizzy cap . They can get a hairline crack and ground out . It can happen at any time . I would check them in the dark by turning the engine over and if there is a crack you will see the spark jump .
Could be a fried coil wire...pretty common with those old graphite core wires. Check for discoloration on the metal ends.
well, i guess maybe the cap wasnt touching the rotor, cause when i bent the tab up a little i started getting a weak spark, then i cleaned the plugs and it runs, so.. i am still stumped. but it works so, whatev, thanks all who answered!
I have had all kinds of oddball things happen with Mopars. Had a bad cap, it worked fine until it got cold or real damp then the car stopped. Had a bad dust protector on the coil wire at the coil, new wire old dust protector, same thing, worked fine when all was warm and dry. Once had a ground wire in the distributor break so that when you were idling or going slow it worked great, make the vacuum work and she stopped, as soon as the engine shut down, just hit the starter and she was fine until the vacuum advance worked. Took about two months to find. Found it purely by accident. Moved the ground wire and noticed that it was broken inside the insulation. Had a rotor go bad. Idled just fine, as soon as the engine began to warm up the engine would start missing this kept up and kept getting worse until finely it started backfiring out the card and the tailpipe. Lots of fun. By the way this was a brand new rotor and cap.
wow, the adventures to plymouth rock. thanks guys, now that it runs, i am gonna start pulling my new parts off until it doesnt run anymore, than at least i will know what it was
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