I have a 93 ford E 350 van with the 7.5 460, 4x4 conversion. I have had it parked for 3 months, with it being started periodically. i got home today and drove it for and hour and a half or so. when i started driving it the voltmeter was reading high in the normal zone, around 16 for the battery. as i continued to drive it the amp check light came on, and 30 minutes later the volt meter for the battery had dropped to close to 8 and the van started running poorly, until it simply stopped running when i was close to home. i had it jumped and it cranked after 5 minutes or so of charging. i made it home with the voltmeter dropping close to 8 again by the time i got home. what could the problem be? battery? Alternator? seems like the battery possibly wasn't charging? i dunno, not too good under the hood,….learning. any ideas???

 

Definitely *sounds* like the alternator.

2G alternators have always been sketchy.
Replace the charge pigtail per Fords TSB any time the charging system is serviced.

If you test and replace the alternator be sure to fully charge the battery *before* you run the van again.
Alternators are meant to top it off and handle running loads, not bring a battery back from the dead

 

X2 on fully charging the battery.

Most of those chain auto parts stores can test your alternator if you pull it off the engine and bring it in.