1966 gets hot and quits.

[jimrmac]

I recently acquired a 1966 Fleetwood and when I drive it about 15-20 minutes and turn it off, it wont start back. The other day it actually quit running while i was driving it but I was close to home and coasted into my driveway. Believe it is electrical issue. Tested spark at the coil and got none while cranking although I did get a spark each time I turned the ignition off. It sat overnite and today got spark at the coil wire to distributor while cranking so I replaced the coil (thinking it must be the culprit) and drove it again for about 15 minutes, turned it off, let it sit for about 10 minutes and it wouldnt start back. Same issue again, no spark from  coil. The coil I replaced looked fairly new and I replaced it with a good one from NAPA so Im thinking a distributor issue? I should note also that previous owner replaced points and condensor with an Accell brand electronic ignition (similar to the Petronix one I guess).

[Jeff Rosansky CLC #28373]

Next time it happens, check power TO the coil.
Are there any other systems that don't work? Does the rest of the car still have power?
Has it happened when cold? Do you have fuel in the carb?
Need a few more details please.

Jeff

[jimrmac]

Power to the coil was good, car is getting fuel, I dont think that is the issue. Car runs fine and quits without warning or just wont re-start. At first, it could sit for about 15-20 minutes and it would re-start. Today it sat an hour and still wouldnt start so I pushed in the shop and went home. (my shop is not at my house). Besides coil, what else ignition related can fail under operating temp conditions?

[CadillacRob]

Not sure if you did away with it for the pertronix ignition, but ballast resistor?

[jimrmac]

Not sure either since conversion was done by a previous owner. Where is the ballast resistor located on that car? I will look next chance I get and see if it was removed.

[Scot Minesinger]

Check all the ignition wiring connections to ground, make sure they are tight.  If not the expansion of the screw when hot could just be enough to weaken a marginal ground connection.

[35-709]

Not sure if you did away with it for the pertronix ignition, but ballast resistor?

There is no ballast resistor per se on that car.  Cadillac used a resistor wire connected to the pink wire from the ignition switch, the resistor wire begins at the engine side of the firewall connector.  If like the Pertronix, the resistor section of the wire should be bypassed possibly be tapping into the pink wire inside the car before the firewall connector.  The car WILL run OK, by the way, by not bypassing the resistor wire but the system will not be performing at the level desired or intended.  The electronic systems really need a full 12 volts to operate at proper levels not the 6 or 7 provided after start by the resistor wire.

It sounds like a good possibility to me that some component in the Accel ignition setup is suffering from heat failure.

'66 Cadillac Factory Shop Manuals are readily available on eBay. 

[CadillacRob]

Not sure either since conversion was done by a previous owner. Where is the ballast resistor located on that car? I will look next chance I get and see if it was removed.

That new coil you installed should say either "use external ballast resistor" or "internal ballast resistor" or something to that effect.  If not, I'm assuming its like the earlier models, it'd be up on the firewall in the engine bay.  Look up the part and then you'll know what you're looking for.

[35-709]

   ?  Am I missing or misinterpreting something here?  There is NO ballast resistor on that car, only a resistor wire as noted.

[Scot Minesinger]

Believe so, no ballast resistor.  Your 73 (maybe sold now) was probably that way (my 1970 is and so is 72 Caddy I recently worked on).  Have run into problems once and a while with that wire and I install a replacement ballast resistor with nor resistance wire.   

[35-709]

Do not have the gumption to research just when Cadillac started using a resistor wire instead of a ballast resistor but it was prior to 1965.  IF someone added a ballast resistor to that car because of problems with the resistor wire, there is no telling where it was located since it was not factory --- jimrmac asked where it was in Reply #4 above. 

[jimrmac]

Checked car today and my shop manual, apparently there was no ballast resistor, just a resistor wire like those in previous posts have stated. A yellow wire and black wire from the original wiring harness coming from the firewall attach at the (+) terminal on the coil along with a red wire that seems to be part of the Accell unit wiring. Green wire from same unit attaches to the (-) terminal on coil. All connections on the coil are tight, I'll pull the cap and rotor off distributor this weekend and check connections in there also. I'm still leaning toward a malfunction in that Accell unit so I may change it to a Pertronix or even go back to points and condensor, at least temporarily, and see if that changes anything. One more question- could it be trouble in the starter solenoid or ignition switch? Car cranks over fine even when there is no spark but since juice from the battery to the coil runs through those it had me wondering...

[CadillacRob]

Sorry, only coming from experience with my 50's cads, so perhaps there was none from the get go by that year.

To answer the other question the starter solenoid is what engages the starter motor when you turn the key.  So no, I dont think that would be the culprit of it randomly dying while running. 

Id have to do more research, but I feel like I've read guys having this problem and the starter switch itself being a problem.  Whether its a bad connection or the switch is on its way out.  Could be a stretch but look into that possibility.

[Ralph Messina CLC 4937]

This is a long shot suggestion but easy enough to check. Both '65 &6 had ignition switch issues when they were used cars. The plastic plug that connects to the ignition lock would heat up and start to melt shorting across the wires possibly  leading to dash fires. Lift up the dash pad and have a look at the condition. It was not a frequent problem but friends who worked in the dealers at that time warned me about it and told me to get a spare plug.

[Alan Harris CLC#1513]

Ditto! I had a 1965 convertible back around 1970. I had that exact problem with the ignition switch and was told that it was common.

[Jeff Rosansky CLC #28373]

The switch was one of my first thoughts, but he says he still has power TO the coil when the car dies.
Jimrmc, please confirm this. If not, you can just run direct power to the coil and drive the car until it heats up and see if it dies. This would bypass the ignition switch.
Jeff

[jimrmac]

Yes, when the car dies, I still have power at the coil when I put my test light on the (+) terminal. When I remove coil wire from distributor cap and put end of wire near metal, I get no spark while cranking. However, it does produce a quick spark each time the key is turned from the "on" back to the "off" position. I can turn the ignition key back and forth from off to on (not start) position and I get a small spark each time.

[jimrmac]

OK, to recap; Since automotive electronics make my head spin sometimes, tell me where I'm wrong. Since I am not losing power at the coil when the car gets hot, it would seem that the problem is not with the resistor wire, ignition switch, or any component between battery and coil. That leads me back to the distributor, possibly loose connection under the cap or a problem with the Accell unit itself. Is that a good assumption? Ruling out the coil itself for now since replacing it with a decent new one didn't solve the problem. Thanks everybody for the responses to my post! First time to post on this forum.

[Ralph Messina CLC 4937]

Jim,

I’m not familiar with the requirements for a Petronix ignition but I believe it uses its own special coil with a much higher voltage output. If the Accell unit needs a special coil, the unit may be effecting performance of your standard coil. It would be interesting to install points and a condenser with the present coil and test whether the car shuts down. If it runs properly the problem is in the Accell electronic ignition unit or it’s compatibility with the coil.

Ralph

[35-709]

A "hot" coil is recommended by Pertronix but not necessary.  I have satisfactorily installed several Pertronix I systems --- among those, 3 on 1966 Cadillac engines and one on a 1973 Cadillac as well as a few non-Cadillacs.  I have never changed the coil from stock on any of those installations and all have performed well and reliably.