My 401 nailhead buick electra was tooling down the road just fine and it quit. I diagnos a No Spark condition. I do a full tune-up, plugs,points.wires,cap,rotor-still no spark. I replaced the coil-still no spark. I ran a 12volt jumper from battery to the coil and still no spark. I used a test light at the points and the light flash's when the engine is cranking-so the distributor is good. Last night I actually held the spark plug wire in my hand while engine is cranking and I can feel a very weak spark but its not enough to fire a spark plug. I'm at my wits end!! Anybody have any suggestions????
I'd be leaning towards something with the distributor. You've replaced everything else. If you know you're getting a good 12 volts to the coil and that the ground side of the circuit is good that's about the only thing left. Check your powers and grounds but I'd be thinking internal distributor problem....the system is simple enough that there can't be much else. Just a guess. DId you replace the condenser with all of the other parts? Jay
I get a weak spark and spark knock when I drink light beer! Seriously, you could just have a loose ground on the coil. The fact that you do get a weak spark may be indicative of a poor ground. While checking all connections try a little dielectric grease to help keep them intact. Good luck and keep us updated.
You've covered all of the majors, it's gotta be something silly. If the wire to the points set flexes with breaker plate movement (advance) I'd change it out. Make sure the breaker plate has good ground path all the way back to the battery. Good luck.
I too, had problems with points style ignition systems......after replacing a ballast resistor, coil, points, condenser, cap, rotor and wires my Plymouth ran rough at idle, mainly. It ran ok at cruise. i readjusted the valves, ran a compression test (125 lb. all around) and replaced the carb with a NOS carter 1 bbl. and checked for vaccum leaks. It still ran like shit. Did I mention I was (fuck working on cars, just drive 'em) a ASE Master certified tech with 30 years in the bag? I should know how this works. I am starting to get watered off. I knew the motor was perfect....it had been overhauled recently....the problem had to be the ignition. I replaced the points setup with a Pertronix unit and a MSD Blaster 2 coil and replced the plugs with some cool extended electrode NGK units with the gaps opened up to 45 thou..........problem solved......these new coils, points, condensers, etc. are JUNK.......get rid of 'em. I've never seen the like of total shit that is being peddled to an unsuspecting public before in my life.....most of it Chinese junk......The points are made of pot metal, they burn as soon as the engine is lit, I don't know what is inside the condensers or the coils.......although I did notice the MSD coil had a China sticker stuck to the bottom of it.......I thought their stuff was made in El Paso.???? It may turn out to be crap as well.
True ^^^^^ Also: A bad ballast resistor is usually when a engine cranks, but it won't start until the key is released, then it dies... With a Coil, you can check it hot and cold. Check the primary and secondary windings and compare it to spec. Actually all things can be good cold, but once heat gets around it, it fails. A newer HEI setup, the bad ignition module can also be a sign of no spark. Def. check the grounds and make sure power is where it should be. General way of going about a No spark situation is to start with the primary circuit of the ignition system and then go down stream from there... Good luck with finding out the problem...
Little story here. I had a 68 camaro that I put a solid lifter 283 in. I was driving down the road and it starts acting like a fuel pump is bad. I let it set for a bit, she fires right up and about 2 mi down the road...same deal. Condenser was bad. My Dad always use to tell me. if the spark is pink, the condenser is bad and they will not run on a pink spark, blue is hot, pink is not. You can have a spark that jumps a quarter inch, if it's pink it won't run. JMO. Lippy (condenser....condense....hmmm. )
Coils don't have a ground wire. They have a positive terminal that gets voltage from the ignition switch and a negative terminal that goes to the points. No Ground wire. It is, but the lack of one (or a fualty one) can and will create a weak spark. Basically, you need proper voltage to the coil and a good ground inside the dist for the point plate, along with a good ground path for the dist itself. With an operating condenser, and points that are triggering, you should have a strong spark IF the coil is good. One other thing to check, the coil wire itself, in fact all the plug wires.
Very simply; The only part of a points ignition system that provides the high voltage necessary to make a spark jump a plug gap IS the condenser/capacitor. The coil's job is to charge the condenser during the "dwell" time. When the points are closed the coil CHARGES the condenser with an electrical charge. When the points open, that flow of electricity from the coil is cut off and the condenser seeks a ground to deposit it's charge to and that charge collapses to ground back through the coil wire through the distributor cap to the rotor to the designated plug wire and plug. Ya want the eight page version go read a book...
"The only part of a points ignition system that provides the high voltage necessary to make a spark jump a plug gap IS the condenser/capacitor." It depends on the meaning of the word "provides" Might be time to get the book out again
With the fucked up spelling and grammar on this board I ain't arguing stupid semantics over one god damn word. Put up or shut up.
Maybe the coil wire in the plug wire set is faulty? Don't second guess too much. It could be new, faulty part... I'd go back over some of the things that you already changed
I'll jump on the CONDENSER! bandwagon too. The condenser is what kicks back at the coil when the points open. That kicking back is what makes the magnetic field collapse faster and gives the coil a stronger "hit" so the coil output is a whole lot stronger. Condenser first. The other possible item is a failing coil or low voltage from some bad connection. Condensers do deteriorate with age, and since it is the most likely cause, I would just change it anyway. Another possibility is the coil wire as someone else said. I had a similar problem in 1979 and it turned out to be a 3/4 inch gap INSIDE the coil wire. Somehow it kept running for a long long time with a bad cap coil wire terminal until the sparking inside the terminal eventually eroded the coil wire conductor way back into the insulation. Inside the wire it was invisible, and a real pain to track down.
How,s the up and down play in the distributor.Im leaning towards condenser.Distributor grounding out or wrong coil Internal ballast or external Possible bad ignition switch There my top 4 .Dist grounding is my first guess. How old are the wires.
No not quite, maybe you'd better read the eight page version, but here's the Readers Digest Condensed version; When the points are closed, a current of up to ten amps flows from the battery, through the primary winding and away to ground via the points. The current flow produces a magnetic field around the coil windings which is enhanced and concentrated by the iron core. When the ignition points open, the primary current suddenly stops and the magnetic field collapses. The rapidly changing magnetic field induces a sharp voltage spike in the primary winding. This voltage spike is several hundred volts negative with respect to the +12volt applied to the battery side of the primary and because the coil is acting as a transformer, a pulse of up to 20,000 volts appears across the secondary winding. The voltage required to fire the sparkplug determines the maximum voltage which actually appears on the High Tension terminal and this can range from 5000 to over 15000 volts, depending on the plug gaps and the conditions inside the combustion chamber. If a sparkplug lead happens to be disconnected, the secondary voltage can rise to the maximum possible figure and cause unnecessary strain on the insulation of the coil and the high voltage leads. The voltage spike in the primary will strike an energy wasting arc across the just-opened points unless something is done about it. This is one function of the capacitor or condensor connected across the points, an electrical device which has the ability to accept an inflow of current until it is fully charged. Coil current continues to flow briefly into the uncharged capacitor while the points move apart to the point where an arc can't be struck by the few hundred volts of the primary spike. Once the capacitor is fully charged, the current flow stops and the magnetic field can collapse. The voltage spike in the primary rapidly rises to its peak value, inducing the multi-thousands of volt pulse in the secondary. Without the capacitor, the points will be rapidly eroded and the collapsing magnetic field will expend a good part of its energy as a few dozen volts maintaining the unwanted arc across the points.
I feel so stupid!! It was the condenser... Here I thought it wasn't an important part of the ignition. Lesson learned... Thanks for all of your help, and remember that what you think is fact , may not be true.
I have the same problem with a 55 T Bird 12 volt points system. Can it be that I have used TOO BIG of wires from solenoid to the Ballast resister and then to the coil? Thanks .
Went to Colorado (from Missouri) back in '86 with a friend in his Datsun B210. He had his mechanic do a full tune-up just before the trip - plugs, points, condenser, ignition wires, cap, rotor - the usual package. It started cutting out in the mountain roads above Salida. We pulled over and I checked the timing as best I could, checked the point gap, got him on the road as we limped into the next town. A young mechanic went to work on it, quickly diagnosed it as a bad condenser, switched it out and we were back on the road in 30 minutes. He said the brand new condenser was like a lot he had been seeing - shoddy and barely holding together. Another friend with a '56 Chrysler New Yorker with a 354 hemi was complaining about having "distributor problems" repeatedly, and was afraid to drive it for any length of time. I told her to just change out the condenser for another, preferably an NOS if she can find one. She didn't listen, and the last time I talked to her, she was still complaining of the same issue.
Except Don's explanation wasn't complete, and DrJ was right. In Don's explanation, when you get to the point of "Once the capacitor is fully charged, the current flow stops and the magnetic field can collapse." that's not quite complete. It's not wrong, it's just not complete, because there is quite a bit happening after the points open; it's not a one and done type of event. What actually happens is when the primary current stops flowing the magnetic field collapses inducing a high voltage in the secondary coil; but the current flowing in the primary has momentum which cannot be contained by the condenser, and so the current actually reverses direction momentarily which re-establishes the magnetic field in the coil, and then as the charge stored in the condenser falls the current stops flowing again, inducing another current in the secondary, which causes the condenser to recharge via self-induction, and the whole process repeats several times until all of the energy is depleted. When the points close again the entire chain of events begins anew. So for each cycle there are multiple collapses of the magnetic field and several pulses of current are induced in the secondary winding of the coil, which is all dissipated through the spark plug. This all happens in a fraction of a second in time, but electricity operates on a very fast time scale, so there is plenty of time for all of this to occur. The bottom line is, without a properly functioning condenser all of this doesn't happen. The condenser does much more than protect against arcing across the points. https://www.crypton.co.za/Tto know/Ignition/ignition overview.html This article explains it well, and includes graphics which help. Notice that the voltage goes above and below the 0 volts line, indicating that the current reverses direction multiple times per event; which is why some guys claim it is an AC system. eta: also note how high the voltage goes above the supply voltage, that is also due to the action of the condenser; no condenser, no voltage spike, equals weak spark.
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