One time power loss during regen

[jbiersba]

Hey folks,
I experienced a power loss issue over the weekend, which I can't reproduce, but concerns me. Details below, If anyone can provide some feedback it would be appreciated.

truck: '08 F250, 6.4L, 74K miles

Issue: I was driving along ~70mph using cruise control Saturday and without warning, cruise control was kicked off, and I had an immediate loss of power. I was able to maintain speed at ~50mph with very little throttle or boost response, going down hills, and on the uphill, I could barely maintain 35 mph (gentle hills). The transmission wouldn't downshift when I hit the throttle, but I think that's because the motor wasn't producing any power. If I floored the accelerator I could get the RPMs do go up just over 2000RPMs, but no boost to support.

Hesitant to pull over to the side of the highway and strand myself with the family in the truck, I limped along to the next exit (10-12 miles down the road). While I was limping down the road, I ran through the on board diagnostics tool several times. No Check engine lights, no check transmission lights, the only item that popped up was that the truck was in regen mode. Two things to note here. First, in the 5 1/2 years and 74K miles that I've owned this truck, it has never lost this type of power in regen mode before, ever! Second, usually regen lasts 5-8 minutes. During this event, regen just kept going. I monitored it for over 10 minutes, and I assume that regen started before I started monitoring. So, it was a very long regen cycle that didn't terminate (at least as witnessed in the diagnostic screen) until I shut the truck down.

When I exited the highway, there happened to be a Ford dealership, although it was closed, I figured that would be a good place to get stranded if I shut down the truck and it wouldn't start or go. So, I did. I shut down the truck, gave it a minute and then started it back up. I took a ride around the block. Regen mode was no longer active, and I was no longer having power issues. We proceeded on our trip without issue.

I've put close to a hundred miles on the truck since the event, with no further instances, and no error messages.

I'm preparing for an extended trip and this issue concerns me. I'll be traveling 1000+ miles, towing a large load. If this event had taken place while towing, I would have likely had a serious issue.

I'm afraid that since there were no error messages, if I take it to the dealership they aren't going to be able to find anything wrong.

My question is has anyone experienced this type of issue in the past, or can any of the techs out there help explain what might have happened? I see lots of threads about power loss during regen, but none seem to match exactly. I'm honestly not sure whether the regen caused the power loss, or was a result of the event.

Thanks!

[jbiersba]

Forgot to mention. This is a job 1 truck

Thanks

[drewactual]

there are folks here with a much better grasp on what these trucks do than I.. but I may be able to contribute the following:

the cruise will kick off when the truck goes into some sort of pre-limp mode (previous to all criteria being satisfied and illuminating the little wrench on the dash).. I know this to be factual, because I've experienced it, too..

as far as the key cycle is concerned:

upon ignition 'on', and pre-start, the PCM runs a Built In Test (BIT) that takes approximately .4 seconds to accomplish.. it is basically scouring for hard faults.. if there are none, then it's full steam ahead.. if there are, it trips a CEL.. there can also be pending codes that cause this, that aren't hard faults yet but the computer still stores.. during the same BIT, sensors are 'pinged', so to speak, and if the response is within parameters expected, there is no CEL or Limp Home Mode.. if there are, then it tells you..

I tell you about the BIT to make a SWAG that the issue wasn't a hard fault.

I had a loss of a sensor that caused an unannounced limp mode (no wrench) but absolutely wouldn't allow full power to the drivetrain.. I drove it like that for the remainder of my trip, until I got home and replaced the sensor, with no other problems..

the lack of boost you speak of may be a PCM attempting to defend itself from inability to provide fuel.. just a thought.. start with filters.. it seems always a safe place to start with these things.

[Big Angry Hillbilly]

Scan it with an IDS... you may have pending DTC's or codes that an aftermarket scan tool/programmer does not pick up.

[jbiersba]

Thanks, What's an IDS? I haven't scanned it with anything (no aftermarket scanners here). I just ran the on board diagnostics check in the message center.... goes through electrical, fuel, brakes, air filter etc..... and then tells me that the exhaust system was cleaning.

I've been driving all week without issue How long would the codes remain in memory? If I swing by my dealership is it something they could check quick do you think?

[Big Angry Hillbilly]

IDS is the Ford diagnostic tool.

They should be able to check it for you, probably charge you an hour's labor for it minimum though.

That system report/diag center thing doesn't get terribly in depth into engine stuff, just basic stuff like fluid levels and stuff like that.

Hope this helps.

[f250ghost]

Just happened to me this morning! It was like the truck high idled itself but i had no control over the throttle...once my foot came off th brake pedal the truck would throttle itself up...luckily i was close to and on my way to the dealer and limped it there

[05_PSD_Erik]

Delete it.....

But seriously, I agree 110% with Big Angry, get it scanned by Ford. The one hour labor charge could point to a coming issue and end up saving you a LOT of money in the long run. Especially with an upcoming long trip