85 Charging problem
Thread Starter
Heel & Toe
Joined: Sep 2010
Posts: 15
Likes: 0
85 Charging problem
When i start my 85 the battery only charges at 11 volts but after running for about 15-30 minutes it charges fine. im going to go get the battery and alternator test tomorrow, was just wondering what else it might be. thanks
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
have the alt and battery tested.Check connections to alt. On the back side of the alt. there is one connection that is held on with nut that I think goes to the battery. Be sure that the connector is large enough for the wire. Too small of a connector will play havoc with the charging system. Check to be sure battery cable connections are clean and tight.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
If You rev up your Corvettes engine up to 2,000 RPM's, Does the Dash Voltmeter read at least 12.6 V ?
Nomally it should read around 13.2 - 14.4 Vdc.
If the Alternator does not sustain a voltage level of at least 12.6Vdc output, then the cars electrical system usage draws from the battery alone. The alternator cant keep up with the vehicles electrical demand.
Be a good idea to load test the battery in Corvette.
A Sun Vat 40, Snap On battery load tester, or an Autometer battery load tester all work great for testing.
If You have a Fluke style DVM or even a Radio Shack multimeter that can read DC voltage,
take a reading off off the back of the alternator charging post ( heavy 6guage RED wire).
Take the reading at engine idle(600-800 RPM's).
Then Rev up the engine up to 2,000 RPM's.
Should have around 13.2 - 14.4 Vdc.
Underdrive crankshaft pulleys a previous owner might have installed will cause a low charging condition at low engine idle speeds.
Have an underdrive crankshaft pulley on my 87.
Doesnt put out much at engine idle. At 2,000 RPm's I have 14.4vdc.
Underdrive pulley was installed by the previous owner of my Corvette.
BR
