Demons in my Porsche!
 

Hi all. This is one I haven't seen on here yet. Here goes. 1997 Boxster with new starter, battery, ignition switch. If i don't disconnect the battery at night, no start, nothing at all.
When I drive it and turn it off, it will not start. Here's the weird part. If I disconnect the battery, wait about ten minutes, re-connect battery, it fires right up! What am I "resetting" by disconnecting the battery? Any and all help greatly appreciated in advance.
Also, after I drove it today and it would not start, I checked the batt and had 12.9 volts.

To me, it sounds like a problem with the grounding on the starter.

Do you have power (dash, radio, etc) but it won't start or do you have no power whatsoever?

If you have power (dash, radio, etc) but it won't start, check the clutch interlock switch.

If no power at all (everything is dead), then I agree with checking the grounding cable. Be aware that the cable can look perfectly good on the outside but can be corroded internally.

Yes I have all power, and I bypassed the clutch switch.its just strange that if I disconnect the battery when it won't start, wait about ten minutes, re-connect the battery and it fires up with no hesitation.
Thanks for your input.

So if you come home in the evening, shut the car off, pull the battery cable off for 10 minutes, reconnect it and wait 8-12 hours the car 'fires right up'? Is that what you are describing?

Or is it that your car 'fires right up" only works right after the reconnect of the battery cable and thus shortly after the shutdown?

Is this car new to you? Was it ever in a flood or water under the seats situation?

Was the starter solenoid replaced?

If you just turn it off and wait 8-12 hours, what is the battery voltage? Any lights on the dash then when the starter doesn't engage?

Trying to figure out if a relay is hanging, a battery drain is occurring, or if the replacement ignition switch is suspect?

Definitely check under the driver seat for water past or present.

I misunderstood the Topic Posting... I thought my ex was in your Porsche....

LOL! That would be an easy fix! Went out this morning after leaving it hooked up to the battery all night. Batt showed 12.9, so no parasitic drain. Would not start. Disconnected and cleaned the quick disconnect and it started, but it would do this before as long as I left the battery disconnected for about ten minutes. Hopefully this will fix the problem. I will keep you guys informed. Thanks again to all!

Well tried the cleaning, same problem. When I was checking the fuses, the fuel pump relay fuse just fell out of the holder. Pushed it back in, but nothing is holding it. Could this be the problem. When the car starts, it runs perfect.

Yes.......

For what it's worth, putting multimeter leads from post to post is not a way to check a battery's health.

It needs to be load tested, say at your local O'Reilly Auto Farts store.

Curious to see what your electrical gremlin is.

Had battery and alternator checked at AZ' No probs. Will keep you in the loop when (and if) fixed.
Regards