Expy died with no warning and then revived itself. Thoughts?

[JimmyC]

Clean your battery terminals

 

[JerryT]

Hi all,

Yesterday on my way to a job site, after a 45 min drive, 20 of it in stop and go traffic, I just got off the highway and started up a slight incline when the Expy shut down. No power, revs to 0, Red Check Gauge light came on, Oil Pressure was at Zero (!), still had electrical power. Engine just died with no warning at all. No shudder, vibrations, hesitation, nada... out of the blue like I turned it off.

Drifted to side of the road, shut off the ignition, powered back on and it started right back up, thankfully! Drove the rest of the way to the job site, no problems. Checked all fluids and battery connections.. all good. Started and drove 45 mins back home 5 hours later, no problems. No Check Engine light or codes.

Sooo WTH? What could possibly cause this? I keep the truck maintained with MC consumable parts (oil, filters, fluids, etc), oil was at 3/4 mark and amber, engine doesn't make any rattling or other weird noises at idle, 256k on the clock. Plugs and coils in the past 25k, new fuel filter, recent ish oil/filter change.

My short list are: Fuel filter/pump, oil pump (!), something in the timing?

It's a 2004 4WD XLT 4.6 2V.

Thoughts, ideas? I want to run this down before it gets worse. Don't want to ignore a potentially catastrophic problem, like oil starvation or timing that could leave me stranded.

Thanks!

Sounds like you might have a bad battery. I still have a 1998 Expedition my wife bought brand new in 98, had a similar thing happen to me and it was the battery.

 

[texasscot]

Sounds like the common Fuel Pump Relay problem (R303). Original Omron 15amp relays were not beefy enough, they overheat and melt. By 05 they figured it out and redesigned the system. My wife's '03 had the same symptoms a year or so ago - driving along with no trouble, then would just shut off. Pull over, turn key off, wait a few, then it would fire up like nothing had happened. Would do this every few days, especially on hot days. I pulled the fuse box from under the passenger dash, disassembled, removed the old Fuel Pump relay (visibly melted), and soldered a new (updated) relay in its place. Been perfect since. Make sure you get the updated relay. They are cheap and readily available on Ebay. Old relay - Omron F8VF-BA. Updated relay - Omron G8QN-05. Sometimes they can really get hot and damage the board, and the whole thing will need to be replaced. There were a number of people on ebay offering a full rebuild of the board, but a visual inspection when you pull it should tell you. It isn't that difficult of a job. Took maybe 45 mins. Search Fuel Pump Relay in this forum, you'll find LOTS of threads. Might even be one pinned at the top of the 2nd Gen page.

When mine failed there was no visible damage to the plastic cube but there was some strangeness to the solder on one or two of the pins on the back of the board.
My symptoms were identical to yours; it either ran perfectly or just cut out. It was happening with increasing frequency though, which was quite disconcerting.

 

[Stephen Dunster]

I had this happen on an '06. The connector on the fuel pump in the tank was black and charred from a loose fitting connector. Had to have fule pump replaced in a shop 200 miles from the house after it totally quit and I got stranded.