Acts like dead battery, but it isn't
 

I have a '97 with the 4.6L, after parking it, tried to start it again and it acted like a dead battery when I turned the key. I put a charger on it and it fired right up. Once I turned it off, everything was dead again - no dome light, no dash lights, no radio, etc. After a minute or 2, the lights come back on, but as soon as I turn the key, everything goes dead. Unless I have the charger on it, then it fires right up. I thought it was the battery, had it tested and it is fine. In fact, they gave me a new replacement anyway - but the problem has remained. I checked the cable to the starter and it was tight.

I'm frustrated and at a loss - HELP!!

did you try checking the alternator?

No, I haven't. Do you mean the connections or having the alternator tested to see if it is bad?

If it were bad, would that create a break in the connection on battery only power, but allow power to flow when the charger is on it?

When I thought it was the battery, alternator guage was reading high.

Try checking both. What does it do when you try and start it? Does it do nothing, click, or crank but no start?

Without the charger on it, it will click once or twice sometimes. Sometimes it doesn't even click. Then everything goes dead - dome light, dash lights, radio, etc.

After a min. or 2, there is a click (as if something resets) and these lights come back on.

With the charger connected, it cranks over perfectly.

In regards to checking the alternator itself, are there any tricks to doing it myself, or do I need to take it to place to have them test it?

Could it be the cable connections at the battery? Have you cleaned them?

If it were just clicking i would say starter but the lights are going too, so use a battery meter gague or some sort of thing like this http://www.bepautomotive.com/products/rv-vm-12v.lg.jpg
if the battery is ok then it should be the alternator. i think you can take it to autozone or somewhere and they can test it for you. i cant really think of anything else besides that or loose connections maybe, but i doubt it

MILKTHEGOAT - Thanks!

BLUEJAY432000 - The cables are clean.

maybe check the ground cable where it grounds to the frame/engine

x2 thats what i was thinking... maybe corroded?

One of your battery primary cables or its connection is bad.

To isolate, connect a digital voltmeter from the battery post to where the cable connects and have someone hit the starter.

A good connection or conductor will read little to no voltage when making this test.

A bad (higher resistance) cable or connection will read anything up to full battery voltage.

Steve

To clarify - are you saying to disconnect the battery cable from the battery, then connect the voltmeter between the 2 so the current goes through the voltmeter?

If it were a bad cable, wouldn't it be bad though whether I was just running off the battery or connected to the charger? Or would the current potentially still flow because of more power being pushed by the charger?

Thanks for the help!!

Do NOT disconnect the cable to check for voltage drop. You're checking to see if what should be a solid connection actually is.


Just do it...

Steve

Thanks! I will give that a try and see what I can find.

Check your connection at the starter itself. I had the terminal at the starter corrode right off on my 98 4.6 . Just a thought.
,Dan :coffee: