I have a 1987 Firebird Formula with 19K original miles. It has the 305 TPI engine and 5 Speed Manual. I bought it 20 years ago with 15K miles on it. There has always been a small parasitic drain on the battery that has gotten much worse over time. The pull down hatch motor and the radio antennae have been disconnected since they stopped working. The battery usually goes dead within a few days if not the next morning. If I try to start it with a fully charged battery from cold usually the key turns and all the gauges come on and the fuel pump runs. The volt meter goes way to the left to about 8 volts as long as I hold the ignition key in the start position. If I put the battery charger back on and in the 10 Amp mode the car usually starts up fine. We tried to do a parasitic test with a digital multi meter but the headlight motors keep trying to run with the meter inline with the battery negative cable. The plastic gears on the headlight motors are stripped out so the motors just run for a few seconds and then stop. We checked the voltage across each fuse but did not see anything unusual there either. The original owner had installed one of those UNGO BOX alarm systems on the car. I disconnected the siren he had under the hood soon after I bought it because it was in the way of the battery and I never used the alarm as the car is always garage kept. I do not have any schematic drawings for it and I do not know if it would disable the ignition system. I remember the alarm went off once while I was driving it. I am thinking it may be the starter motor or the starter relay? Someone told me the ignition key has a security feature in it but I would think the fuel pump would not be running if that was keeping the car from starting. Any ideas? Thanks!

 

It's probably the alarm. Unplug the box and see if that eliminates the drain on the battery. Just disconnecting the alarm siren isn't going to keep the box from getting power.Unplug the box and see if that eliminates the drain on the battery.