Grampajac

Hello, I am new here, (first Post), I have a 91 for F150, 5.0. I have been have charging problems for the last several months, and have tried almost everything I can think of. New battery (2 mos). New starter selinoid, I had the alternator checked, and it was good. I pull fuses that I felt could be pulling a load on the battery. Cables/wires tested fine. I charge the battery, and it's good for 10 to 14 days, then no start/power. If any body could help I would greatly appreaciate it, I'm going to go to vermont to see my new grandaughter, and wouldn't want to have problems on the way.

Grampajac

Fast Hampster

Welcome to the forum! It looks like a loose connection. Try this test - start the engine, turn on the headlights, and disconnect battery (+) for a few seconds. If it will not stall - it means the wires are fine, it's the battery connectors issue. If it will stall - the problem is in engine grounding or wrong alternator connection

Grampajac

I tried it, the headlights on and disconnect + cable, and truck kept on running.....

what next?

Grampajac

Fast Hampster

Incpect the battery connectors for any rust or dirt an the inner side. Clean them with sandpaper. Connect the battery and start the engine. Check the voltage on a battery connectors (not wires, battery itself) - it most be more than a disconnected battery. If it is that way - everything if fine and it should be charging.

Rick

I had the same problem and it was the alternator itself that was draining the battery. The alternator was charging ok but the diodes in the alt. were gone. try using a volt meter to check the battery and see if voltage goes down after half an hour or so if it does then unplug both connections on your alternator then check voltage again if voltage then doesn't change then your alt. will probably need to be replaced. hope this helps.

Good old Bill

Thinking along the same line as Rick said, if a common test light is available, disconnect the negative battery cable, connect the test light between the cable and negative battery post. Make sure all doors are closed, ign is off, and hood lite is removed. If the test lite is on there is a draw. No lite, system is good. Because the present day vehicles have alot of keep alive memories, the test lite might glow dimmly. Its best to use an ammeter utulizing the milli-amp scale to know exactly how much the draw is. Because the test lite or ammeter is connected in series with the battery circuit any short or current draw has to go thru the test lite to get to ground. Thus the lite goes on, or the ammeter reads the amount. If I am making any sense at all, and you do have an ammeter, pm me and I will explain some safe guards necessary to avoid burning up the meter. The test lite might fry the bulb but thats cheap.