Sudden No Start

[DanMan68]

My 1977 with a 3.2 swap was running perfectly, I had just taken it for a 20min drive and got everything up to temp, then stopped and shut off the car for a few minutes. Went back to start it again, there was a "click" then nothing. No fuel pump, no action at the gauges, no starter click or turnover. Thankfully this happened in my garage, I checked the fuses (none blown), wiggled the relays in the front fuse box, wiggled the connections to the ignition switch (as much as possible) -- still nothing. The light in the frunk still works.

I'm guessing the ignition switch went bad finally? How to tell if I need the full $900 assembly:
https://www.pelicanparts.com/More_Info/96434791701.htm?pn=964-347-917-01-M100&bc=c&SVSVSI=0563

Or just the switch?
https://www.pelicanparts.com/More_Info/96461301200.htm?pn=964-613-012-00-OEM&bc=c&SVSVSI=0563

Is there a relay or fuse hidden somewhere that could be causing this that I should check? I figure if it was the starter relay that the fuel pump would still turn on, but I am getting nothing when I turn the key.

[brianlay]

You need to troubleshoot with a 12v test light or a voltmeter and see where voltage is present or not. If you’re willing to do that folks here can walk you through the steps.
If you just start throwing parts at it you will likely waste a lot of time and money

[boyt911sc]

Check your battery and cables first.

Tony

[brianlay]

If your 3.2 swap includes the original electronics the fuel pump only runs when the engine is cranking.

[ant7]

Check earth strap from engine to body too, bad connections here will cause all kinds of problems, I had a very similar issue years ago, car would start fine, take it for a run, then go to start it again, just a click, check all the simple stuff first.
Hope this helps.
Ant.

[Schulisco]

Supposingly its the ignition switch.. But you have to rule out if its a mechanical or electrical problem:

https://forums.pelicanparts.com/porsche-911-technical-forum/348306-ignition-switch-inside-fix-start-lockout.html

https://forums.pelicanparts.com/porsche-911-technical-forum/348306-ignition-switch-inside-fix-start-lockout.html

Thomas

[jlex]

When my '85 would do that intermittently, it turned out to be the braided ground strap beneath the engine.

[KerryM]

Very similar to what happened to my '78. I was convinced it was the ignition switch. Several folks on the board suggested checking grounds. My negative battery terminal was a bit loose and the ground straps from the battery to the frame and from the engine/transmission to the frame were pretty corroded. I replaced and tightened the battery cable and replaced the engine ground strap and the issues were solved.

So you may well need a new ignition switch, but check the easy, cheap stuff first.

[DanMan68]

Update on the situation. Went back to the car and it turned back on once, then died again. Checked battery voltage, OK at ~12v. Tried again and it started right up. Voltages at 14v when running. Been driving it all week and no issues. Will check and clean the battery terminals and ground strap to be safe. Thank you everyone for your input. Still a bit of a mystery but hopefully after cleaning everything there is no reoccurrence.

[MrBonus]

I had a similar intermittent issue. It turned out to be an ancient starter.