Electrical power issue when key turned to start position

1984 308 GTSi QV Euro car

New battery (and headlights light up if switched on). I turn the key to position 2- red lights on, buzzer buzzes, some clicking from relays, and the fuel pump runs for a few seconds. Turn the key to start, there is a click or snap noise from the engine area I think, and electrical power is gone, no start. If I turn key to off and turn back to position 2, nothing, no dash indicators, no relay noises. Also, the headlights will not shine on.

If I disconnect the battery and wait an hour (and battery on charger just to have best charge), and then reconnect battery, I get headlights when switched on. Then in position 2, get red lights, buzzer noise, and relay clatter. Turn to start and all goes dead.

The 308 has not been started for two years. The 12 year old former battery in it was on a trickle charger, but I did not notice it was not holding a charge. Before getting that new battery, we attempted to start the car, got dash lights and fuel pump noise, but would just barely turn over. So, we then attempted to start with the Schumacher charger set on “engine start” mode, which is a 30amp supply with a 100 amp 3 sec max jolt. Loss of all electrical power.

I’ve looked for an overvoltage protection relay near the ECU, but there is nothing there on this Euro car. The shop we used for years, DiFatta Bros, closed a few years ago, so I have no trusted source to call now.

I appreciate any guidance you all could share. Thanks in advance!

 

With charged battery and key turned to start (and red dashlights showing), the loud click is from the rear and then loss of all electrical power (no dashlights or headlights).

The car had a rebuilt Bosch started installed 4-5 years ago. Since the car has sat not started for three years, could the starter solenoid freeze up? And then short out causing all electrical power loss?

If I disconnect the battery and then reconnect, headlights will light up and battery shows good charge. I've never seen a loss of all electric like this situation and I wonder what allows electricpower to return by disconnecting and reconnecting the battery

 

Thanks for that troubleshooting guidance. We regretted using that engine start mode seconds after doing it.
1. That white distribution connector looks calm, no evidence of melted insulation or distorted plastic.
2. It looks like I'll need to get under the 308 to unfasten/fasten the wiring to the alternator and then the starter solenoid. I'll report back this weekend.

Thanks!

 

To report back on this unusual situation, no cause was found. The car was trailered to Rosso Service in Forest Hill MD, and they did not experience electrical issues with the car. Instead, a no start situation they found was a stuck plunger in the fuel distributor. Once freed, car started and continued to start.

I did clean battery terminals and triple checked that connector called "battery switch" along the negative cable from the battery. The female end on the negative cable is cracked but the connection was still solid.