starting issues, switched out ignition switch
 

Advice needed. Car sat for 3 weeks. Tried to start and nothing. So used friends 900MA charger and it started up. A couple weeks later started it again, nothing. Tried to jump it with standard cables. nothing. Replaced with new battery, since old one was 6 years old. Tried to start it. nothing. Even tried to jump it with regular cables.nothing again. Grabbed my neighbors 900MA charger and it started. Drove for 30 minutes on highway and came home. Dead again. Jumped it with cables, nothing until i left it running with donor car for over 10 minutes and it started.

I even switched to a new ignition switch nothing.

SO, is it my starter or alternator?

THANKS guys in advance. Going to take it to Porsche mechanic next week.

Im going to wait until the 900MA charger is full again and try to jump it. If it starts, than what could it be?

This could be :
1. an intermittent fault
2. a high resistance in the starting circuits.
Let's assume it is high resistance.
Use an Ohmeter ,starting at the battery terminal and work through the system.
It is a tedious and pains-taking process. Flailing/guessing not recommended.
Check the battery cable for severe corrosion under the insulation- slit the insulation along the length of the cable several inches and check.
Ground connections corroded?
Horrible work when it is cold/wet.But so is walking !

Yeah hoping its not some high resistance break in the line.

Do you have a multi meter - even a cheap one? If so proceed as follows - its not too difficult:

1) Check the battery voltage across the terminals - should be +/- 12.6v fully charged.
2) If less than 12.6v (which I suspect - it sounds like the battery has lost a cell) then the battery requires charging. Driving for 30 minutes is NOT enough to charge the battery fully - it requires 6-8 hours on a battery charger. If the battery still won't hold 12.6v after charging it needs replacing.
3) To quickly check the alternator, with the engine running attach multi meter across the battery terminals and check voltage - it should read 13.8 - 14.5v @ 1500rpm. Anything less than 13.5 and the alternator / voltage regulator is suspect.

These are just quick checks just to verify its something simple (like a new battery required) before giving the car to a repairer which can = big $$$.

Steve, I borrowed my friends voltage meter and its higher than your described readings, so I'm suspecting its my starter, which I'm hoping is not too expensive :( anyone have any idea how much that is? I purchased new battery and its still struggling starting. My one friend thinks when I use the big charger, its pushed the starter around enough to catch a good position and thats why its able to start the car unlike the conventional car to car charging.

Thank you for your thoughts! I was hoping it was just the battery but it seems its the starter.

Do you guys think aftermarket starter is ok as oem?

If the problem was the starter - why does it start when you use the big charger?
Just connect the good(?)battery with a very long jumper cable to the starter +ve .Be careful ! Chances are it turns the starter really well !
So we are back to high resistance in the wiring .
I am presuming you already checked the starter relay by using a small jumper wire and the clutch interlock is by-passed?? Both well covered if you google.

ok Thanks Gebster. I think its beyond my expertise at this point. going got see what my german mechanic thinks :) Was hoping it was an easier fix.

I purchased a rebuilt Bosch starter from Pelican last year & they sent it to Australia cheaper than I could get one here. They levy a core charge up front which is redeemable on returning the old starter. I looked on the Pelican website for you and a rebuilt unit is $227.
It takes about 3 hours removing the old & fitting the new, but if you are uncomfortable its probably wise to get your local mechanic to run a couple of tests on the existing starter system.
Let us know the outcome.

Steve, I ordered a new one from eBay, 70$! vs a refurbished one $200 with core charge. They eBay one didn't even have a core charge ! :)

I also know a reliable porsche demantler, who quoted me a working one for $45.

Which option do you advise?

Im leaning towards the new one from eBay.

RESOLVED: Defective battery from Advanced Auto! They saw a big drop in voltage immediately after the engine was off. Switched to another new battery and it started just fine!

Thank you for everyones thoughts !

Bingo - sounds like a collapsed cell. Glad you found the cheapest option .......

me too ! Thanks for helping me brainstorm Steve! all the best

Great News!
Aren't you glad we talked you out of replacing the starter motor? :-).