1984 corvette crossfire TBI
05-01-2016, 11:07 PM
#1
1984 corvette crossfire TBI
I just purchased a 1984 Corvette and it started fine when I brought it home. Something is killing the battery. I disconnected the negative battery cable and connected a test light to it and and then touched the test light to the negative battery post and the light came on. I know that tells me something is pulling juice. I had my son hold the light on the battery while I pulled every fuse, but the light did not go out. I have checked all the ground connection for the car and they are connected. My son did say that when i pulled the fuse for the LCD that the light flickered. What else do I need to check?
05-01-2016, 11:22 PM
#2
Race Director
Using a test light in this way is not a valid test for parasitic draw. You need to use an ammeter. You may just have a bad battery or a charging system problem, or perhaps a parasitic draw.
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johnfbass (05-01-2016)
05-01-2016, 11:33 PM
#4
charging system
You say it might be a bad charging system. The alternator looks new, but I wonder if it is the correct alternator. The wires had been spliced and new connectors had been put on. Should I take the alternator to the parts store and have it tested and see if they can tell me if that is the correct alternator?
05-01-2016, 11:39 PM
#5
Race Director
You say it might be a bad charging system. The alternator looks new, but I wonder if it is the correct alternator. The wires had been spliced and new connectors had been put on. Should I take the alternator to the parts store and have it tested and see if they can tell me if that is the correct alternator?
Well that doesn't sound encouraging because it wont work if its not wired properly, but before you have it load tested at the store, I would suggest you get the car started and measure voltage at the battery with the engine running. In the event its under 13 volts then something is wrong with the charging system. Normal voltage with the engine running should be around 14.2 or so.
05-02-2016, 12:18 AM
#6
Race Director
What your light is showing is that the car has parasitic draw which is normal. You need to check the amount of electrical draw to see if your amount is abnormal.
05-02-2016, 10:45 AM
#7
Burning Brakes
05-02-2016, 01:36 PM
#8
Racer
as mentioned in previous posts, there's alway voltage applied to the ecm to maintain the clock and vram settings. This will draw a very small amount of current normally (a couple of milliamps or less). If you don't run the car often, or if the battery or alternator are weak/not functional the battery will eventually drain. if left idle for several weeks the best options are to use a trickle charge maintainer or disconnect the battery. If you attach an ammeter and read a current draw larger than a few milliamps you most probably have a short somewhere in the wiring. Most circuits are fused so pulling one at a time may localize the short. A few circuits have fusable links you'll need to disconnect manually to test. foreign objects in the cigar lighter and the under-hood lights are the most easily checked and likely suspects. Good luck with your '84.
05-02-2016, 01:40 PM
#9
Burning Brakes
as mentioned in previous posts, there's alway voltage applied to the ecm to maintain the clock and vram settings. This will draw a very small amount of current normally (a couple of milliamps or less). If you don't run the car often, or if the battery or alternator are weak/not functional the battery will eventually drain. if left idle for several weeks the best options are to use a trickle charge maintainer or disconnect the battery. If you attach an ammeter and read a current draw larger than a few milliamps you most probably have a short somewhere in the wiring. Most circuits are fused so pulling one at a time may localize the short. A few circuits have fusable links you'll need to disconnect manually to test. foreign objects in the cigar lighter and the under-hood lights are the most easily checked and likely suspects. Good luck with your '84.
+ check the electric antenna