So, I get in my 1966 3.4 MK2, put the key in, turn it on, and I hear the gas pump start up, the ammeter goes to discharge, all set to start. The ignition light is on. I press the starter button, there's a snap and bingo, no power at all. Nada. Darkness reigns.
Up goes the hood, battery is okay, 12v are measured. Fuses are ok. So...is it the ignition switch?, the "control box" which looks suspiciously like a voltage regulator, or???

Tomorrow I try to chase down the voltage from the battery into the wiring. But, if you've had a similar blackout, I'd like to hear about it.

Thanking you in advance.

 

Is there 12 volts coming to the starter solenoid when the start button is pressed?

 

Make sure it's out of gear with the park brake on.
Manually push the solenoid on the fire wall with you finger.
If it turns over, then you have a bad connection on the push button switch inside the car.
Now turn the key on and see if it will start by pushing the solenoid with your finger.

If it does not turn over, check your connections to the starter and battery as well as the big cable connections on the solenoid.

Solving electrical problems is a process of elimination.

 

The electrics on the Mk2 to are stone age compared with a modern car and simple to follow, understand and repair if as Jeff says you use a process of elimination.

First the voltage regulator runs from the generator and as your car was not running it cannot be this. The voltage regulator is a device which as the name implies regulates the voltage from the generator. A modern alternator will push out 12 to 13 volts all day long no matter what speed it rotates at. The generator will produce anything from 6 to 15 volts depending on its speed of rotation. The voltage regulator just stops the voltage going to the car and battery from exceeding 12 to 13 volts.
Having eliminated the VR your problem lies somewhere in the twisted metal that is your wiring loom. If you have a electrical test meter now is the time to get it out and chase the wires.

Power goes from your battery to your Amp meter and ignition switch when the key is turned and to the fuel pumps. When the key is turned power goes to one side of the starter button. When you push the button power goes to the solenoid on the bulk head and flicks a switch. Power goes from you battery to the solenoid on the bulkhead and when the switch is flicked by the starter button power goes to the starter motor and the engine starts.

As Jeff has suggested start with the solenoid as this has a button on it which basically acts as the starter button on the dash. If this is pushed with the key off the engine will turn over but not start. With the key set to on if the button is pushed the car should start. If it just turns over and does not fire up we need to look further in to the car.

As you seem to have lost all power I would discount the solenoid as what normally happens is the switch that the starter button flicks in the solenoid can stop working but the symptom of that is you have power but the car will not turn over on the button. Not in your case so as you have no power on the ignition switch we can ignore it.

If you have no power it means something has happened between the battery and the ignition /key.

Main fuse is the first thing to check behind the dash panel. Don't just check the fuse but check that the fuse is seated correctly as the holders can get dirty or loose and give a bad connection.

Amp meter. Power goes from the battery via the ignition key switch to the amp meter and if the amp meter blows power will not flow as you want it to and everything switches off.

The ignition switch itself might blow as it is only a set of wires with a bar that rotates and connects them up. If this again is dirty or does not function as expected no power.

It should not be your push button starter switch as this just takes power from the ignition key switch and transfers it, when pushed, to the solenoid on the bulkhead. If this does not work you will still have power, fuel pumps will work and the button on the solenoid will still start the car.

So to conclude I would check the continuity from the battery via the solenoid (power from the battery to the main wiring loom is on the same connector on the solenoid and so is not effected by a non working solenoid) to the Amp meter and ignition key. I would check the Amp meter and ignition key to make sure they are working correctly and check you fuses are intact and seated correctly in the fuse holders.

Hope this helps.

 

Checking the wiring and chasing 12 volts today. Thanks to all the suggestions.

 

With no load, battery = 12v. With a load, battery = 0. All the wiring was old, but ok. Replaced the battery and all is good. Thanks again for the advice.

 

Glad we could help and that you got it sorted in the end.

 

Lessons to be learned. A fully charged 12V resting car battery (12 to 24 hours with no charge for "surface" charge to dissipate) should yield about 12.9 Volts at an ambient of 25 deg C. Probably no less than 12.6V if much colder.

The only way to really check battery health is to load test it which any battery shop or good parts supplier can do.