99 Explorer starts, runs, then dies...completely

[mune237]

My son's 99 Explorer died on his way to work yesterday.
He got it towed back to the house, then got a ride to work.
Afterwork I grabbed my OBDII reader and headed over there.
His mother works for Motorcraft, so she grabbed a new alternator and battery.
But when we get there, the explorer starts right up and runs fine.
But dies after 15 minutes. Really dead!
It acts like someone pulled the battery out. No electricity at all!
I wasn't able to get a CEL reading w/o power to the ign switch.
I know electrical problems can be anything with these 13 yr old cars, but does this sound like a typical Explorer problem?
I have NO history with these FORD Explorers.
My Volvo had a bad -B- battery cable, that was typical as the cars reached 10 yrs old. I never would've found it, if it wasn't for the SwedeSpeed forum. The cable looked absolutely fine from the outside.
TIA
~Mune

 

[imp]

Check all the cells in the battery with a hydrometer. If all are "charged", after the engine dies, go for likely an intermittent connection somewhere, not necessarily at the battery terminals.

To check further: after it dies, with ign. key still "On", go in and see if the EEC Power Relay is energized. As a starting point, no EEC relay "ON", no engine run.

imp

 

[mune237]

Thanks for the reply "imp"
To clarify, when the explorer died, there wasn't any electricity running anywhere. It was like someone stole the battery.
I'm not a FORD guy, but I'm guessing the EEC Power Relay is in the fuse/junction box.
How do you check if it's energized?

 

[Willcall]

Maybe try the alternator? If it went bad it'll just run down the battery and the car will die.

 

[mune237]

Update: Was able to get it started with a new battery. But only had time to get it back into the garage. (raining hard here in WA state)
It did stay running longer than the day before. It didn't shutdown either!
More testing this weekend, starting with the charging system.

 

[imp]

The original post indicated a new alternator had been installed, no? imp

 

[98ExplorerGuy]

I had somewhat similar problem which turned out to be a bad cable end on the battery positive terminal.

 

[imp]

I had somewhat similar problem which turned out to be a bad cable end on the battery positive terminal.

The very first place to look for trouble! Also, the easiest to get to first. imp