Low starting volts.
Thread Starter
4th Gear
Joined: Feb 2021
Posts: 4
Likes: 0
From: Livingston MT
Low starting volts.
I have an 85 corvette that runs great, but when I start it, it is somewhat slow and comes on with about 10 or 11 volts but it has been as low as 9. I fix this by revving my engine up to around 2600 rpm when I start the car (it starts on its own without the revving and can drive but stays at low volts) and still have it in neutral, then it jumps up to the proper 14 volts and stay there for the rest of the ride. It does this even if I just got done driving for awhile, turn my car off, and start it again immediately after. I got a brand new battery when i got the car, not that long ago, and I have had the alternator tested and it's fine. What could be causing this problem?
Drifting
Joined: Jun 2013
Posts: 1,590
Likes: 60
From: ft myers FL/Munising MI
if you can get it to do it at the auto store when they put the load test on, they can tell you if it's the alternator or battery.....or connection somewhere.....I put one of those gear reduction starters on my 85....ridiculously small but starts in a milisecond...
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I don't have a wiring diagram for an '85, but have you checked the voltages at the regulator harness connector? The older alternators needed voltage (from an idiot light or equivalent) to supply initial/startup current for the alternator field winding. If the connector doesn't see power on that line during startup/idle, the field won't energize, and the alternator won't charge the battery unless you rev the engine up so that the increased alternator RPM can produce current from the small amount of residual magnetism in the rotor.
Just a thought.
Just a thought.
Thread Starter
4th Gear
Joined: Feb 2021
Posts: 4
Likes: 0
From: Livingston MT
I don't have a wiring diagram for an '85, but have you checked the voltages at the regulator harness connector? The older alternators needed voltage (from an idiot light or equivalent) to supply initial/startup current for the alternator field winding. If the connector doesn't see power on that line during startup/idle, the field won't energize, and the alternator won't charge the battery unless you rev the engine up so that the increased alternator RPM can produce current from the small amount of residual magnetism in the rotor.
Just a thought.
Just a thought.
