Yeah, I know this is an oldie. But I would like to get feedback on the mysterios discharge syndrome - sort of a poll. I checked my trunk lite, fuse block, headlite motors for a small whine, and had the alternator check. Is there any really weird ones that I have missed. Don, t need the embarassment of having to jump the 84 again! TG

Also, the strange one is that fuel injector failure instead of a dying starter is what seems to be the first infected. The starter turns but the injector does not kick in until the car is jumped. New top of the line battery only seems to last 3 days and reads 11.88 volts when I experience the problem. And battery charging lite in vehicle indicates 13.5 volts while driving.

What else can I add???

Another flustered 84 owner, I guess. TG

check your fuel pump. if that is on constantly, then you oil pressure sender unit is bad. mine was like that, but now it has fixed itself. but the oil pressure gauge pegs out. i am changing mine out to a newer styled one.

Check voltage at the battery with a good meter. If it is still below 14V then likely the alternator is bad or there is a serious wiring problem. Bad SI series units are known for killing the battery thru either/both over charging and slow drain when off.

Unplug the headlight door motors. Those are good for this on 86 and older. See in my cave for more items to look for.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

The ECM will not turn on with less than 9 volts (it is 9 right?) the voltage could well be dropping below that when cranking if the battery is weak. Without the ECM the injector would not fire.

As for the power leak, try removing several fuses at a time and seeing if it bleeds down. I would start with the tail light fuse, as that is what powers the down motion of the headlights.

You can also take a DMM with amp settings. Take off the positive terminal from the battery, and place the DMM inbetween the positive wire and the battery. Make sure the headlights and everything are off, you will blow the fuse or burn up the DMM if you over load it.

With it in there, it will tell you how many amps are flowing out of the battery. It might jump up a bit at first as the ECM and radio standby circuits energize. After a few seconds it should stabilize. I dont know what is normal, but there will be a little. Once you get a reading, start pulling fuses or disconnecting circuits, watching to see if one in particular drops the amps.

Two possibilities:

1) Shorted diode(s) in the alternator. The alternator will still charge the battery when the engine is running, but it will drain the battery when stopped.

2) One or two bad cells in the battery itself. A healthy lead-acid battery produces ~2.1 volts per cell, so the nominal battery voltage (measured at the battery with a good meter) after sitting overnight should be ~12.6 volts. If you measure ~10.5 volts at the battery after it has been sitting a while, this suggests that one cell in the battery has probably failed. Next, measure the voltage at the battery with some load (e.g. lights or ignition switch on); the voltage should drop slightly, but not a lot. Finally, measure voltage at the battery when cranking; it should drop no more than a volt or two. Any voltage measurement less than 12 volts that is an approximate multiple of 2.1 volts may indicate one or more failed (or failing) cell(s).

As Ogre has stated, a bad battery or alternator will often cause the other to fail, too.

[This message has been edited by Marvin McInnis (edited 06-27-2008).]

Thanks everyone for replying. I will definitely keep in mind for the future about the ECM shutting off at less than 9 volts when the somewhat discharged battery is cranking the motor over. That occurence really threw me off track. The discharge problem occured as a result of a combination of a sensitive door courtesy lite and slightly loose hinge pins. If the door was not completely closed (even though it appeared to be) the lite would come back on later. It took a week for me to prove it out, plus the fact that somehow a bathroom remodel project somehow took priority, so sorry for the delay in responding. You people in this forum have really helped me in the Fiero education process.