Ok, I have a 1968 Plymouth Belvedere 5.2L stock. I just finished replacing the timing chain on it. I fired it up, it ran smooth for a day then started idling rough and died. Reset the point gap, same thing. Ran great for 2 days (drove around town and everything.) then idled real rough and died. This has happened about 5 times now. Each time it runs great (occasional misfire but for the most part idles smooth) then just runs rough and dies. Pull off the distributor cap and play with the points and all is good for another day or so. Each time I look at the points they are a little black and rough. I had thought that they were bad at first so I swapped them out, same thing happened. New points were dirty as well, but not as bad as the old ones. I even have a spare distributor so I swapped it out, same thing happened. When I reset the points it has started up, ran smooth for a minute, then idled rough, smoothed out, then rough again. This happened a few times while I was playing with the point gap. I thought I just didn't have the gap quite right so I would go back and adjust it again and this seemed to fix it. Each time it runs smooth for a day or two and dies. Tried new coil and condenser. New points, new distributor and no matter what the same thing happens. It has new plugs, plug wires. I checked the voltage at the coil and got 6.5 ~ 6.9 volts, is that normal? What else could possibly be causing this issue?

 

burnt points? off the top of my head two - 3 things it could be. 1. the ballast resister has been by passed. 2. the distributor is not grounding the points plate. once i put a wire right on the points plate, to ground. 3. engine ground wire missing. OR convert to the chrysler electronic ignition. Mopar dist cap wiring
My dad made this saying about V8 small and big block dist cap wireing. To reduce wiring confuseion. “the small block has the dist in the wrong place, in the back of the engine. BUT the shaft rotates the right way clockwise. The big block has the dist in the right place, in the front of the engine BUT the shaft rotates the wrong direction counterclockwise. Both wire #5 and #7 on both ALL ways have #5 before #7 on the cap AND block. And most / some stock V8s have the fireing order cast in to the intake manifold.

 

I will check the Ballast Resistor when I get home, that should be easy enough. But how can I tell if the distributor is grounding the points plate? Also, this is the same problem with 2 distributors, so am I doing something wrong when I adjust the points? One thing that I did notice is that with the old distributor I have to set the gap at .016 to get it to run at all. On the new distributor I had to set it at .018. So I just wonder if the gap itself had anything to do with it?

 

first check the OHMS of the coil. pri res 1.4 to 1.78. sec 9400 to 1170. ballast res 0,5-0,6 OHMS. and check the dist bushings if they are loose it can cause all kinds of trouble. ill bet on the bushings. to check the plate ground, engine stopped, points closed. ignition on. set VOM on the lowest DC volt 1- 3 volt. put one probe on the plate the other on ground at bat. cant remember the exact number but ill guess if its over .5 that might be bad. then put a separate ground wire from the plate to the bat ground. and see what that does. an other thing that might work is to check the amp draw running / stooped.