[Yellowb1rd]

Hey Pelicans,

It's been a while since I've been on the forum. Last summer, I finally got the supercharged 928S4 running, and running well. It ran like a bat out of H@!! until about three weeks ago (I was driving it as a daily), and started experiencing issues which puzzle me. I understand that 928's can kill batteries if left sitting for more than a week, but I kept mine charged (for the most part) to avoid that. On my way back from the office a few weeks ago, I noticed that the battery was dead, which required a jump.

I figured that I had left an accessory on or something (i accidentally left the door cracked open in the parking garage all day.) Predictably so, I knew the car wouldnt start, and got a jump. I also noticed after starting the car that it had developed a knock which was quite loud (dont know if this is related). The knock quieted down after it got warm. That night after getting home, I charged the battery to full (using a noko Genius charger), and the next day it started, and I drove it to the office again. At days end, I went to start the car, and found that it would barely turn over, but it did, and after about 15 miles, the car started to sputter as if out of gas (it was low on fuel), and I thought that was the culprit. I never thought that it was electrical, since according to the voltage guage, it was putting out almost 14 volts. I pulled of the freeway to get some gas, and after about a mile the car started violently shrugging, until it just died. I tried to start it, and it behaved as if the batter was dead.

Anyway, I happened to be very close to an auto repair shop, and asked the mechanic for a jump, but the car behaved exactly the same way. it would barely turn over (and the digital display would barely pixelate). Then the tow truck driver tried with his unit, and same thing. I suspected it could be a bad battery, or bad starter, and I checked both after getting the car home. Battery is 8 months old, and checked out with my voltmeter, and also a third party test showed it was fine. Then I removed the starter, and had it tested by alternator/starter specialist -It checked out fine. I verified that the grounds were tight, so I'm out of ideas. Can anyone point me in the right direction.

The motor in this car is a replacement with low miles, and I replaced the oil pump, timing belt, CPS, knock sensors, put in a portensioner, and had the cams reground to factory specs before putting it into the car.

Does anyone have any ideas? That knocking bothered me, but I dont think that is the problem. It seems like an electric issue to me, not a motor seizing. Always something with this car, and I'm at my wit's end with it.

Thanks all for your insight.