1966 Lemans Intermittent Ignition Issue

[Shep1966]

I’m having an intermittent problem with my 1966 Lemans. It’s happened about 6 times to me so far. Seems like it happens after I’ve driven a little while. I get in the car and it won’t even turn over. I have battery power to everything, just nothing happens when I try to start. I wiggled the wires behind the ignition switch and it fired off.

It happened this Sunday after a 2-hour drive. Wiggling the wires didn’t resolve the problem. I’m not sure if I have a wiring harness issue or an ignition switch issue now. I made a hot wire jumper and plugged it into the harness and started the car. I then put the harness back on the car hoping it wouldn’t start, but it fired right up! Does anyone have any experience with these things? Are there any known issues that happened after the car gets warm?

 

[melsg5]

Have you removed the switch and looked at the connector?

 

[Shep1966]

Have you removed the switch and looked at the connector?

Haven't done anything yet. I looked up how to take the ignition out I can do that next. At least clean the contacts etc

 

[avell007]

I would recommend replacing the ignition switch reguardless , it could be a bad connection if so new pig tail also plus the switch.

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[omologato]

I have battery power to everything, just nothing happens when I try to start. I wiggled the wires behind the ignition switch and it fired off.

Your last sentence leads me to think avell007 is correct in the ignition switch being the problem. BUT, your first sentence will need clarifying.

When you say you have battery power to everything what is "everything" exactly?

Basically the next time you have this problem the best way to determine the cause is to have an assistant handy and have them turn the key over while you check for Battery voltage to the starter motor itself and work your way backwards. If it is the ignition switch you will have no battery voltage to the solenoid or starter when in the "start" position of the ignition switch.

Connect DVM in set to read DC volts, Red probe clipped to the fat power cable on the starter motor stud and the black lead of the meter to Battery Ground. While turning the ignition switch to the "start" position do you have 12v to the starter motor? If you do then it's not the ignition switch or start solenoid. It's either the starter motor, or you have a bad engine ground where the starter motor can't sink enough current back to the battery to complete the current loop. Starters, especially old ones require a lot of current to function properly not just the appropriate voltage. You can have 12v to the starter motor but not enough current to roll it over.

 

[Classics Fan]

I’m following this thread with interest as I’m having the same problem with my 68 LeMans. It started fine when I pulled it out of the garage. I shut it off then five minutes later nothing when the key was turned to Start. There is no power to the starter. There is also no power to the right hand side of the fuse panel in either Run or Accessory key positions. The dead side of the panel has fuses for accessories like heater blower, radio, wipers, etc. I’ve eliminated the possibilities of a bad fusible link and grounds. When I jumper 12 volts to the starter it cranks and jumping from from the left side of the fuse panel to the right side provides power to the jumpered accessory (blower motor in this case).

I had to drop the ignition switch below the dash panel to get access to the wiring to test through the switch. Unfortunately 3 wires came off the switch spades. I don’t know which wire goes to which spade and I don’t have a wiring diagram. I’ve got one ordered and it should arrive by Tuesday. When it arrives I should be able to prove a bad switch. In the meantime I searched high and low for an ignition switch and it seems there’s a nationwide back order. It’s been in order for a month from Parts Place. When I checked with them a week or so ago they said they expected it in about 3 weeks from then.

 

[omologato]

I’m following this thread with interest as I’m having the same problem with my 68 LeMans. It started fine when I pulled it out of the garage. I shut it off then five minutes later nothing when the key was turned to Start. There is no power to the starter. There is also no power to the right hand side of the fuse panel in either Run or Accessory key positions. The dead side of the panel has fuses for accessories like heater blower, radio, wipers, etc. I’ve eliminated the possibilities of a bad fusible link and grounds. When I jumper 12 volts to the starter it cranks and jumping from from the left side of the fuse panel to the right side provides power to the jumpered accessory (blower motor in this case).

I had to drop the ignition switch below the dash panel to get access to the wiring to test through the switch. Unfortunately 3 wires came off the switch spades. I don’t know which wire goes to which spade and I don’t have a wiring diagram. I’ve got one ordered and it should arrive by Tuesday. When it arrives I should be able to prove a bad switch. In the meantime I searched high and low for an ignition switch and it seems there’s a nationwide back order. It’s been in order for a month from Parts Place. When I checked with them a week or so ago they said they expected it in about 3 weeks from then.

Sounds like your problem is the ignition switch since bypassing it for both accessories and starter motor shows the circuits for each are functioning fine.

If you need to make up something until parts become available it's quite easy with a 68 LeMans.

First you need to bundle anything that requires power while the key is in the "run" position and use a toggle switch, single pole single throw on/off switch. This will be the "run" position part of the ignition switch. Next for the start circuit use a momentary switch, single pole on/off. Basically to drive just get in car and flip the toggle switch then push the momentary start switch to start. To shut the car down just flip the toggle switch to the off position.

I live right near Ames in New Hampshire, have you called them to see if they have an ignition switch in stock? Ames Part Detail

If anyone actually needs the starter motor I have three on hand. They are original OEM vintage starters that were rebuilt. I just need to keep one for myself as a spare for my 66 GTO. The style I have is the older style which I think they used up until 67/68? If anyone inquires I'll double check to make sure it fits your application.

 

[Classics Fan]

Sounds like your problem is the ignition switch since bypassing it for both accessories and starter motor shows the circuits for each are functioning fine.

If you need to make up something until parts become available it's quite easy with a 68 LeMans.

First you need to bundle anything that requires power while the key is in the "run" position and use a toggle switch, single pole single throw on/off switch. This will be the "run" position part of the ignition switch. Next for the start circuit use a momentary switch, single pole on/off. Basically to drive just get in car and flip the toggle switch then push the momentary start switch to start. To shut the car down just flip the toggle switch to the off position.

I live right near Ames in New Hampshire, have you called them to see if they have an ignition switch in stock? Ames Part Detail

If anyone actually needs the starter motor I have three on hand. They are original OEM vintage starters that were rebuilt. I just need to keep one for myself as a spare for my 66 GTO. The style I have is the older style which I think they used up until 67/68? If anyone inquires I'll double check to make sure it fits your application.

Thanks for the information. Since the car was on the driveway when the problem began I was able to push it back into the garage where it’s safe and out of the way, so no need to rig up a work-around. I had looked at the Ames switch but is not OEM compatible and preferred to try to stay with original-type parts. I may revert to ordering it if the OEM-type switch continues to be unavailable.

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[omologato]

I had looked at the Ames switch but is not OEM compatible and preferred to try to stay with original-type parts. I may revert to ordering it if the OEM-type switch continues to be unavailable.

Does it work with your lock cylinder or would you have to buy a new lock cylinder to fit the switch?

If you do wait, you really don't have to cut into any of your stock wiring, just use male spade terminals to connect into your wiring and tie all the wires that need power in "run" and connect to a single throw on/off switch. Do the same for the start circuit but use a momentary non-latching on/off switch. Both switches can be purchased at hardware stores but are more expensive there than online. At least that way you can use the car with ease until the OEM style comes back into stock.

I don't want to get into politics as it's forbidden on most forums but this country is in shambles right now and I can't remember a time when it was this hard to find auto parts. At first customers were getting really annoyed but I think at least now they know it has nothing to do with me and nobody can get parts right now like we should, fast and cheap.

 

[Classics Fan]

Have you removed the switch and looked at the connector?

When I got to this I found a bit of a mess left by a previous owner. Long story short, the wire feeding power to the switch had come loose. Problem solved. I second your suggestion to the original poster to check these connections.

 

[omologato]

the wire feeding power to the switch had come loose

That will certainly cause starting problems!!

You wouldn't believe the amount of bad wiring messes people even professionals leave. If I need to wire in a new stereo harness or remote starter etc... I follow mil-spec soldering standards with heat shrink insulation around connections. It looks professional but more importantly is rugged and will withstand people tugging at harnesses during repairs etc...

Glad you got it figured out.