On Going no start

[22dog22]

Just a bit of the story, 69 Cuda, 318 auto, have installed Pertronix dist and the correct coil, have been tracking down issue of no start. Last item on list was to replace the coil to dist. cap spark plug wire [ did replace the whole set of plug wires, but coil wire need to be longer due to where I have the coil mounted], and unhooked the electric choke wire I had hood to the coil. The other day I was able to try to start the car again, it seemed like it wanted to fire while in the crank key position, but as some as you left the key god to run , it did not want to try to fire any longer [ TO NOTE THERE IS NO RESISTER BLOCK] so I think I have lost the run power going to the coil from the ignition switch, I think I need to install a relay to keep power [ 12 volts] going to the coil so the car will start. Since I do not have power that will stay on from the ignition switch , in the run position , where under the hood should I pick up 12 volt switched power source for the relay trip power?

 

[67Dart273]

Easy to check. Clip a test lamp or multimeter to coil + and ground, turn the key to "run". Should have power. Twist and hold the key to "start." Should have power.


First I was under the impression that Pertronix used a ballast.

But regardless here is how this works

There is only 1 switched 12V, from the key, coming into the engine bay, in the RUN position of the key. THIS GOES DEAD when the key is twisted to start. Often this is dark blu, "IGN1". This supplies loads such as ignition system, alternator field, voltage regulator, electric choke if used. IT IS NOT fused
AGAIN, it GOES DEAD when the key is twisted to start

During cranking, "start" there are TWO separate power sources into the engine bay, from separate contacts in the key. One is the normally yellow "start" wire which fires the start relay and the sater

The second, normally brown, is IGN2, the ballast "bypass" circuit. This connects to the coil + side of the ballast resistor. IF YOU DO NOT use a ballast, you MUST jumper the IGN1 "run" and the IGN2 "bypass" together at the power point for the ignition system, ALSO making certain, that you did not cut loose any of the other needed loads in the branch

 

[22dog22]

Ok , up date, I was able to replace the coil to dist. wire, I unhooked a wire that I thought was powering the electric choke on the carb. but after rechecking was the power for the ignition wire for the run power to coil. So at this point, when I try to start car, wants to run but acts like timing off [ 100 % sure was on number 1 by compression to fined number 1] , tried to move distributor timing , both retard and advanced but acts the same no matter which way I try to adjust. do have spark plug test light on number 1 plug, shows spark however is not a bright white/blue color , only a orange/red color.

Have checked power [12 volt] to coil at crank and run of key, reads 11.8, again I do not have the factory electronic system no resister block, I am using the Pertronix system, [dist. and correct coil] I am not sure why I am not getting a hot spark as what I am told the spark plug tester light should show. Have all new spark plug wires, plugs have less 500 miles on the , NGK GR4GP ,pulled them are clean. This whole problem started end of last year, kept getting harder to start, car was then parked over the winter in my garage, in early Feb. of this year we had a couple of warm days, so I took a look at the car, tried to start, needed to fill tank with gas, took a shot of starter fluid to get it going, drove about 1 mile to gas station , filled tank , was hard to restart but did run, seemed to run good, as I was pulling into the garage , it died coasted in, was not able to restart.

Fast forward to May , when weather was warmer, again try to start, had a cheap aftermarket dist. and matching coil in car.
car started, but seemed like the way it started timing was off, as car was running wanted to check the timing, so as I unhooked the vac. hose to the dist. the car just shut off, and could not get it restarted even with a shot of starter fluid, so I thought since I touched the vac. unit on the dist, that something was wrong with the dist. To which started with replacing the aftermarket dist. and the correct coil for it, as stated above , had to replace the spark plug wires since the Pertronix is a taller unit and could not use the male terminal cap , so I could not reuse the spark plug wires I had , replaced with new spark plug wires, but the coil is not mounted on the engine, but fender well , needed a longer coil to dist, wire. So that is where I am at.

So as this post starts out I am lost as to where to go from here., The funny thing is I have been working on the car for over 13 years, have had it running for about the last 3 years, only in the last year or so , all this started to happen !

 

[67Dart273]

Get as far down to the basics as possible to check spark. You want to use a WIRE core coil secondary wire, even (for testing) if you have to temp use a low voltage wire, just hang it in space

"Rig" a test gap, either buy a gap type tester or open up a good spark plug so the gap is wide

you might even unwire the coil / Pertronix conection and just jumper battery power direct to the coil/ pertronix.

Make CERTAIN the dist. has a good ground (hold down bolt loose? == poor ground, maybe, that is where the Pertronix gets power

So with power jumpered to the Pertronix, and cranking, you should get nice hot snappy blue spark at least 3/8" and typically 1/2"

There is always a possibility the coil is weak. Coils do not necessarily go completely bad. Heat often causes coils to 'come and go.'

There is always a possibility the Pertronix has a problem.


So if you are getting 11V to the Pertronix during cranking and no good spark, it HAS to be either the coil or the Pertronix. Again, make CERTAIN the dist. is "tight" for ground

If that part works/ good spark, then concentrate AKA are you really for sure getting 11V to the coil/ Pertronix during cranking, with the wiring properly connected?

Once again, I think Pertronix normally recommends a coil with a ballast

WHY IS THE BALLAST USED and why is it "good?"

You hear a lot of "bad" about ballasts, but frankly I have not replaced very many. I am 75 had mopars back in the SEVENTIES

The ballast, when the car is running and charging at 14V, keeps the coil at maybe 11-12V, "it varies."

Due to the key starting circuit, IE IGN1 "run" and IGN2 "bypass" the coil ALSO normally gets about 10-11V during STARTING

So if you eliminate the ballast and to to a 12V coil, NOW what happens is the "12V coil" (a misnomer, they are REALLY a 14V coil!!!---Now that 14V coil is only getting 11V during STARTING. So keeping the original ballast and ballast type coil combo in there causes a hot spark during cranking.