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

[Al Steel]

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!

 

[99WhiteC5Coupe]

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!

I would inspect (and clean if necessary) the inside of the throttle body bore.

 

[Fastcar]

If it were the fuel pump it would probably stumble a bit before shutting down. I would think that your oil pressure would be at 0 in a shut down situation. You said it ran fine after a re-start. So, as much as it sucks, you could chase this forever. I'd lean strongly to electrical voltage drop, but from where?

 

[whtbronco]

I'd check for codes to start with. As noted this could be tricky to locate, but any available codes should help. Sadly there are likely some codes set from the event that were a result and not the cause.

 

[Hamfisted]

Sounds electrical. Like you said, like you just turned the key off. Inspect the PCM relay for melted plastic on the relay and on the socket it plugs into there in the fusebox ( top right relay...) . You can inspect the harness plugs there at the PCM and the plugs leading to the PCM. Look for a loose wire or corrosion on the pins. Did your whole instrument panel light up like the key was ON but engine not running ? If the instrument panel warning and caution lights came on that means the ignition switch is still good and the problem is more toward the PCM relay, PCM, and harness under the hood.
Do you know when the fuel filter was last changed ? Just to eliminate that question mark.







.

 

[99WhiteC5Coupe]

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!

The engine oil pressure switch circuit is designed to shut off the engine if the oil pressure drops below a specific amount (7 psi?).

Perhaps the switch is bad, or its connection, which is causing the unexpected shutdown?

 

[Al Steel]

All great replies:
99WhiteC5Coupe - just cleaned and lubed about 2k ago at last oil change. Didn't know about the oil pressure switch, you could be on to something. Going to research that one, any help on where it is and how to test it?
FastCar: my thoughts also. One of the 278 electrical engine control gadgets, wiring, etc. could be just a wait till it happens again issue or it throws a CEL.
WhtBronco: Unfortunately no codes unless they can only be read by a Ford specific "deep" scanner. My cheapo OBDII reader is coming up with nada.
Hamfisted: Great ideas there, going to check tomorrow. Fuel filter changed 8k ago so unless it's defective doubt that's the issue but anything is possible. Instrument panel did not light up. Engine died and the Red Check Gauge light was the only instrument light on. All other gauges were normal except for the oil pressure at 0.

One thing that I doubt is the problem but thought I'd mention... I've recently been occasionally running Sheetz E15 88 octane. I haven't seen or noticed any issue with it and I don't use it exclusively. Just been testing the waters with it. Haven't noticed any performance issues, idling problems, etc but not sure if that could somehow cause this problem?

Btw: filled up with regular 87 from Costco and did a 3 hour trek into the mountains to scope out some future camping spots. Ran fine the whole time. Baffling...

 

[Broncoholic]

Sounds electrical. Like you said, like you just turned the key off. Inspect the PCM relay for melted plastic on the relay and on the socket it plugs into there in the fusebox ( top right relay...) .

Does the 04 have a different fuel pump relay than the 03 that is soldered onto the board? The description is similar to my 03 when I had to replace that relay.

 

[IO40]

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.

 

[HazBeen]