1968 Starting Issue

[Mosesatm]

My T-code has me a bit baffled. When I turn the key to start the car it fires so I let go of the key then the engine dies without ever really starting. After that one almost-start it won't catch again, no matter how many times I turn the key off and on. The engine just cranks and cranks.

I'm thinking solenoid, ignition switch, or coil.

Does anyone have other ideas of what could be going on?

 

[franklinair]

Did you try jumping the solenoid (with the key in the 'run' position)?
If it starts & runs that will eliminate the solenoid & coil.

Neil

 

[Ruppstang]

Turn you key to run and check the positive on the coil for power. If no power I would check the ignition switch. The start circuit was designed to by pass the ballast resistor and give the system 12V in the start position then dropping back to 9V in run to save wear on the points. it sounds like you have lost the power to the ballast resistor.

 

[rvrtrash]

Turn you key to run and check the positive on the coil for power. If no power I would check the ignition switch. The start circuit was designed to by pass the ballast resistor and give the system 12V in the start position then dropping back to 9V in run to save wear on the points. it sounds like you have lost the power to the ballast resistor.

+1, with "ballast resistor" meaning resistance wire to the coil. Do you want me to come over after work some afternoon and give you a hand with it?

Steve

 

[robert campbell]

My guess is the ignition switch itself. I have seen this a few times. Seldom is it the wiring itself. Steve and Dad are right on. In the "start" position 12 volts is provided to the points and coil, via the starter solenoid. When you release the key to return to the "run" or "on" position the power is from the switch though the ballast wire to the points and coil.

Your ignition switch is bad.

Rob

 

[Mosesatm]

I have a remote starter switch so that's an easy test.

Thanks

 

[Mosesatm]

So, it's not the solenoid, coil, ignition switch, or Pertronix unit.
I'm guessing my next task is tracing the run circuit?
Steve, I may be taking you up on your offer.

If I reinstall the Pertronix is it OK to run a 12V wire from the battery to the coil, and then hook up the remote starter? I'm thinking that if it runs by bypassing all the factory wiring there is a short in a wire.

 

[franklinair]

That'l work. In fact, the Pertronix coil LIKES 12V

Neil

 

[p51]

From my experience with the Pertronix ignitor 1 you can either...

(1) Run it with a stock coil (which does not have an internal resistor) and the stock resistor wire (1.5ohm, if I recall correctly) or...
(2) Run it with a Pertronix ("Flamethrower") coil (which has an internal 1.5ohm resistor) and a non-resistive wire hooked to a switched ("crank" and "running") 12v supply.

I originally had setup #1 but found the car seemed ran better with setup #2. I have read threads online where setup #1 does not seem to work in all cases. When I switched to setup #2, I provided the 12v source to the Pertronix coil using a relay with the original resistor wire as the relay control.

Also, I don't think you can use a Pertronix, a non-resistor wire to a switched 12v, and a stock coil. I'm guessing the stock coil would fry.

 

[Mosesatm]

I ran a wire from the solenoid to the Pertonix coil and the car started right up using a remote starter.

I then tested the end of the factory coil + wire and found it had 12V with the switch in the run position.

I attached the factory wire to the coil and placed the tester on the windshield so I could see what was going on when I switched from run to start. The car started right up. WTH!!!!!!

I did detach and reattach the flat 4-prong connector at the firewall so maybe that did something; I have no idea, but I'm done for today. I'll see what happens tomorrow.

Something I did notice on the meter was that in the run position it showed roughly 8.5-9.0 volts but it showed 12V when the car was running.

 

[rvrtrash]

Happy to help you out Arlie. Just an FYI, if you disconnect the coil wire and put a digital volt meter on the wire and measure voltage, it will read 12V because of the high impedance of the meter. You would need to take the voltage reading with everything connected. Is the top of engine wiring harness new or 50 year old original? If original, the insulation is probably breaking down from heat and you may have an intermittent short. I'm confused by the last sentence you posted. You should be reading 8-9V with the car running.

Steve

 

[p51]

I then tested the end of the factory coil + wire and found it had 12V with the switch in the run position.....

Something I did notice on the meter was that in the run position it showed roughly 8.5-9.0 volts but it showed 12V when the car was running.

Note, if the factory coil resistor wire is not hooked to the coil there is no current draw so you won't get a voltage drop across the resistor and you will read 12v with a volt meter.

Hmmm... If I recall correctly when cranking the stock wiring allows the voltage on the coil to go to 12v (I forget just how that is accomplished) but when running it drops down to ~9v with the loading from the coil.

 

[p51]

I ran a wire from the solenoid to the Pertonix coil and the car started right up using a remote starter.

I then tested the end of the factory coil + wire and found it had 12V with the switch in the run position.

I attached the factory wire to the coil and placed the tester on the windshield so I could see what was going on when I switched from run to start. The car started right up. WTH!!!!!!

I did detach and reattach the flat 4-prong connector at the firewall so maybe that did something; I have no idea, but I'm done for today. I'll see what happens tomorrow.

Something I did notice on the meter was that in the run position it showed roughly 8.5-9.0 volts but it showed 12V when the car was running.

Some more thoughts/comments.

(1) Even if the coil is hooked up to the stock resistor wire, if the engine is not running and the Pertronix ignitor is in the "open" position (as if the points were open) you would still measure 12v (I think). To measure anything less than the 12v requires some path to ground for the current to follow.

(2) In the third paragraph you said you attached the stock wire to the coil. Is the coil a stock coil (with no internal resistor) or a Pertronix coil (the one with the 1.5ohm internal resistance)? If you are running a stock 1.5ohm resistor wire to a coil with 1.5ohm internal resistance that might be your problem. The internal inductor part of the coil is seeing a total of 3ohms in that case.

 

[Mosesatm]

Happy to help you out Arlie. Just an FYI, if you disconnect the coil wire and put a digital volt meter on the wire and measure voltage, it will read 12V because of the high impedance of the meter. You would need to take the voltage reading with everything connected. Is the top of engine wiring harness new or 50 year old original? If original, the insulation is probably breaking down from heat and you may have an intermittent short. I'm confused by the last sentence you posted. You should be reading 8-9V with the car running.

Steve

It confused me, too. Just to make sure I was really seeing what I was seeing, I revved the engine and watched the voltage rise with the rpms. Maybe whoever installed the Pertronix bypassed the resistor wire, but if they did that why does the meter show 8.9 with the switch in the (C) location, unless they switched the wires.

 

[rvrtrash]

The resistor wire, a pink wire if I remember correctly, is before the engine harness. It's in the section from the switch to the first connector. Since it is just a resistor, not a regulator, it will change as battery voltage changes, but it shouldn't change by that much unless your voltage regulator is putting out some really high voltage, like full alternator voltage. I think Rob has the answer and it's your ignition switch. Unplug the connector at the switch and plug in one of your spares to see if that solves the problem.

Steve

 

[Mosesatm]

I already replaced the ignition switch, the solenoid, the coil, and reinstalled points. Exact same problem, so I reinstalled the Pertronix.

I'm going to open up the dash today to see if something looks wonky.

Here is a video.
https://youtu.be/riAh8HbGP1U

And another one just for fun.
https://www.youtube.com/watch?v=3qqE_WmagjY

 

[p51]

It sounds like from the posts you are using both a Pertronix ignitor 1 and a Pertronix coil. If so, here is something to note... there are two different coils in the Pertronix catalog. One for V8 (with a 1.5ohm internal resistor added above the stock coil internal resistance) and one specifically for a 6-cyl (with a 3ohm internal resistor added). I don't exactly see how this would explain what you are seeing but it might be useful information...

http://www.pertronix.com/docs/instruction-sheets/40011.pdf

 

[p51]

I already replaced the ignition switch, the solenoid, the coil, and reinstalled points. Exact same problem, so I reinstalled the Pertronix.

I'm going to open up the dash today to see if something looks wonky.

Here is a video.
https://youtu.be/riAh8HbGP1U

And another one just for fun.
https://www.youtube.com/watch?v=3qqE_WmagjY

One thing I noted from your video is the first time you have the key in the "run" position the voltage is around ~6.5v or so and the engine does not start. This may not be a high enough voltage for the Pertronix ignitor 1 to actually function (that may be why the voltage appears to bounce around). Since the ingnitor is electronic (vs points) it does require some minimum voltage to work (and Pertronix recommends a full 12v). The second and third time you started the engine the voltage is ~8.5v (from leftover charge? and the ignitor is happy?) and the engine starts.

The only guess I have about why the voltage actually increases when the engine is running is that (1) the alternator is boosting the voltage above 12v and also (2) the ignitor is switching on and off which (I would think) would appear as an average resistance increase of the coil (1/2 switched on, low resistance + 1/2 switched off, high resistance) over that with key in the "run" position without the engine running. That average increase in resistance would show up as a higher coil+ voltage. But this is all a guess...

 

[franklinair]

Since you've replaced all the usual suspects, here's a simple fix:
Simply run a jumper wire from the solenoid (small terminal, brown wire) to the + terminal of the coil. It will furnish 12V to the coil when the Ign switch is in the Run position.

This way you have the best of both worlds: 12V to the coil in the Start mode, and 12V to the coil in the Run mode. (Pertronix coils love 12V)

Neil

 

[Mosesatm]

One thing I noted from your video is the first time you have the key in the "run" position the voltage is around ~6.5v or so and the engine does not start. This may not be a high enough voltage for the Pertronix ignitor 1 to actually function (that may be why the voltage appears to bounce around). Since the ingnitor is electronic (vs points) it does require some minimum voltage to work (and Pertronix recommends a full 12v). The second and third time you started the engine the voltage is ~8.5v (from leftover charge? and the ignitor is happy?) and the engine starts.

The only guess I have about why the voltage actually increases when the engine is running is that (1) the alternator is boosting the voltage above 12v and also (2) the ignitor is switching on and off which (I would think) would appear as an average resistance increase of the coil (1/2 switched on, low resistance + 1/2 switched off, high resistance) over that with key in the "run" position without the engine running. That average increase in resistance would show up as a higher coil+ voltage. But this is all a guess...

I agree the low voltage is probably the issue, but why is the voltage so low? I still think someone may have switched the resistor wire and the 12V wire.