ericjay47

I have a 2004 porsche cayenne S V8 I had a bad alternator and just replaced it "NOT AN EASY TASK". The car always started before i changed this part with out any issues.

I just purchased one new battery under front drivers seat. The 2nd battery in trunk is bad only has 260 cranking amps.

Now when i try to start the car it makes a rapid clicking sound under the hood. The starter is not turning over and i can not start my car, also can not jump car.

I have fully charged batteries and it started about 5 times and i drove for 2 hours and the new alt is getting 14 volts on dash and car drove perfect.

Now just this clicking sound, and starter not turning over.

Any ideas what this issue can be? I have ordered a new battery and will install today but i can not even just start my car with AAA jump box.

I did not disconnect batteries when i installed the alt and i did touch the positive wire from the back of alt to frame of car arch it for 1 half a second.

95_993

PTEC

Make sure the engine ground cable is connected. I suppose it is possible you may have popped one of the big fuses in the current distributor (under the drivers seat) when you touched the battery cable to the frame. Do you have 12V at the jump connection point in the engine compartment?

oldskewel

I agree on the advice to first double check all your connections. Odd that you were able to drive for 2 hours, and the voltage was showing 14V - that would suggest no problems. But this:
means there could be a real problem in there. If not for your 14V reading, I would have concluded that you fried something in the alternator with that arcing, and the 2 hours was just running on the pre-charged batteries.

nodoors

Yikes. With so many steps, it is an easy thing to forget.

I had a starter relay fail closed one time on another car and the prolonged amperage draw from the starter burned up the connection at the ground strap terminal to the frame rail. It was impossible to tell by looking at it, but I eventually found that to be the reason the car wouldn't start again after swapping the solenoid. It still had some continuity and the relay would click just like yours, but the connection couldn't support enough amperage to get the car started after that. You might have something similar going on after shorting out that fat positive cable.

PTEC's advice is excellent as always with such few words.

0. I would unhook or replace the bad 2nd battery in case it is not isolating correctly.
1. Are you getting within .5v of the battery charge level at the jump points under the hood?
2. Check the ground strap from the frame rail to the front of the alt to make sure it is still tight.
3. Check the ground strap from the battery to the floorboard in front of driver's seat really closely for the potential same issue I described above.
4. Start checking relays/fuses starting with the stuff under the driver's seat

Let us know what you find.