Hi all, First time poster here and I have a rather basic (fingers crossed) question. I have a 1984 Porsche 944 nonturbo with intermittent starting problems. I have narrowed what I need to check down to 2 problems at the moment: The DME or the alternator. However, I also have a battery question for you. ASSUMING the alternator is working correctly and charging my battery (I.E I have close to full charge on my battery), how many times can I try to turn my engine over before the battery will drain? I realize this varies greatly, but are we talking more 5-6 tries or more like 30? I ask because I am having trouble starting after the rain (leads met to believe DME, and I also have a 3 month new battery in there), but after 5-6 gentle tries to turn the motor on (Starter motor turns just fine, but car won't start), the battery is noticeably weaker, as in it won't turn the started anymore. Any help would be greatly appreciated. Thanks!
oh, I should also note that I'm definitely not ruling out both being bad because of the times and circumstances that these problems have manifested themselves.
Hokay, went and got the car back. When I got to my car, everything was dry or at least dried off. I attempted to start without jumper cables and it did not work. I got the cables and the car started on the first turn. I got home and checked the voltage at the battery with the car on: 13.20 volts. I turned the car off and tested again: 12.80 volts. Would a voltage reading in this range seem to indicate a problem with the charging system?
Hal
SuperDork
8/1/14 8:56 p.m.
12.8 with car not running is OK. 13.2 with car running is low. Get your alternator tested.
I will do that first thing tomorrow. Thanks
Another test you can do on the battery is a load test. A simple version of the auto parts store tester. But it does take 2 people. Have some try to start the car while you hold the multimeter probes on the battery. A good battery will drop and then go back up around 10 - 12 volts. A bad battery will stay around 4-5 volts or less and not go back up.
Not saying it isn't the alternator, just giving you another self test.
Dropping below 9 volts during cranking(assuming the battery is fully charged) is a bad battery. A lot of German cars have pretty meh alternators, if you're getting 14 volts at 2000 rpm or so you're probably ok.
