520i will crank, won't start. Bad battery?

Went out to start ole' Betsy, 520i, this morning, and it wouldn't start. It chugged for about 1-2 seconds but then died. You can hear it firing occasionally when I crank it now, but it won't continue. I got 6-7 tries before the battery started getting noticably weaker. I went out a little while ago and only got about 3 tries before it started cranking slower, so the battery is obviously weak. Would the weak battery, though, be the cause of the original problem, i.e car not starting? The motor would crank, but not fire consistently. Just trying to eliminate the easy stuff first.

lol hold down the gas pedal all the way? Happened to me solution was as simple as that but I doubt it is for you too, I guess u could try ya? good luck

Thanks for the tip, but I finally got it to start this afternoon. Had to jump it off my wife's minivan (ugh!). It took several tries, and even after I got it running, it was very rough for several minutes. I let it run for 10 minutes, then shut it down and restarted it. Everything seemed fine then. I was thinking it might be the battery going bad and getting too little juice to the ignition, but it had enough to easily turn over the motor, for at least for 4-5 tries anyway. Fuel pump/fuel filter maybe? Guess I'll see what happens tomorrow morning when I go out to start it.

sounds like you would be safer buying another battery.