low voltage on start

[ianGST]

When I first start my 97 GST my turbotimer reads about 10.8-11.5 volts. It stays at this low level until I really rev on it (3800+), when it then jumps up to 13.6-14.6 or so. I realize the turbotimer is a terrible way to measure voltage but my headlights are VERY dim until it jumps up to where it should be, I have no doubt that I have a charging issue. All that I found while searching were stories of the opposite - cars starting high and losing voltage over time (as the car heats up).

Heres some more information:
- My electrical system is stock other than a boost gauge tapped into the headlights and the turbotimer.
- The car is slow to start, but I'm hesitant to get a new starter because it could be because of this problem. Would initial voltage of 10 or 11 cause it to take a few extra turns to start?
- The battery is about a month old, but it may well be ruined from this stuff.
- The alternator is about three months old and from O'Reilly's.
- I had to replace the negative wire to the battery because the terminal clamp had cracked, and the positive one looks like it might have a tiny crack in it, too.

Any ideas or advice would be great. I imagine its a faulty ground or something, but I guess it could just be a bad alternator too. I need to fix it because I hate having to let the car warm up enough to where I feel okay revving it to 3800 before I even move it.

Thanks in advance,
Ian

EDIT: Also worth noting is that when I do rev it enough to where it will hold proper voltage at idle, the idle speed drops dangerously low. It never fully stalls but it feels like it wants to. A few seconds of rev-holding it at 1200 or so seems to get it back on track. Very strange

 

[n0c7]

When my car has sat for quite awhile or its cold in the morning, it will run at lower voltage for a couple of minutes and then jump up itself and run ok. Never thought it was a problem and does the exact same thing you said. I've got a 95 GST, fairly new battery and alternator as well. I wouldnt sweat it. Not sure about the idle issue though.

 

[ianGST]

My car does this every time it starts, even if I've been driving for 30 minutes and turn it off for only two minutes. Also, during this low voltage period the headlights are so dim that only a fool would drive with them, so I know this isn't normal. Thanks for the help, though. I really wish this was nothing

 

[WillyC]

Best thing to do is check your wiring. Grounding is VERY important. You say you replaced the negative cable...maybe its not grounded very well. Check the wiring on the alternator itself too. Check all the grounds for corrosion...better yet, remove them all and take a wire brush and clean them. If that doesn't do it, you may look into the possibility that the new alternator is bad. It happens sometimes. If you have a friend with a DSM maybe you could try theirs. Then move onto the battery if that all checks out. And yes a poor voltage will lead to a longer cranking time while starting.