08 550 looses power after reaching 75mph.

kevin41 · February 12, 2010

I have a customer who states when he drives his 08 f550 6.4 with a utility bed loaded when he reaches 75mph. truck looses power runs bad then he slows down and stops he will shut truck down then restart and is o.k.untill he tries to go faster than 75mph then same problem have not verified concern not a lot of places to drive this truck 75mph. Ihave checked this truck out acouple of times sft fuel trims always o.k. no codes but always a p1000 in memory customer states he is not clearing one time I did have an overspeed code and a p1000 any ideas you guys have would be appreciated. thanks in advance

jaysonfordtech · February 12, 2010

I would be looking into fuel filters and flow. I have seen on lots of vehicles over the years filters that are restricted or

pumps that fail causing similar concerns.

Aaron · February 13, 2010

Isn't an F550 limited to 75mph or so?

I had one of these awhile back, (albeit an F-350) guy stated it would just 'slow down' after driving it for long periods of time.

Same deal, P1000, and the one time it came in it had an overspeed code.

After extensive road testing, inconclusive.

I eventually got the truck to set a P040D for the EGT sensor. From what I have been told, when this sensor goes out of range, or over temp, the engine de-rates. There is no indication of this on the message center, or anywhere else. The truck will just slow until the EGT comes back into range, and then power will be restored. I guess this sensor was just on the edge of being fucked to the point where it could set a code, but would still de-rate the engine. After seeing the issue a bunch of times, there was a code set for the sensor, but the MIL did not come on, ever.

Just something to look at. I was not given a spec by the hotline regarding what temperatures this occurs at though, sorry I can't help out with you there.

Why is he driving a LOADED F-550 at 75mph, anyway?

Keith Browning · February 13, 2010

I was thinking along the same lines Aaron but he stated that the truck "runs bad" which made me think it is more than a de-rate situation.

kevin41 do you have a more detailed description than "runs bad" like misfires, runs rough, smokes or does it simply lose power?

Fordracer · February 13, 2010

I've noticed a lot of 6.4's with a P1000 in memory and don't know why. I mentioned it to the hotline one day and they don't know why either. You can check the CLR_DST pid and see how long it's been since the codes have been cleared to see if it's been messed with. The ones I've seen it's been several thousand miles since the codes have been cleared.

joshbuys · February 13, 2010

Isn't an F550 limited to 75mph or so?

F250/F350 LIMITED TO 96 MPH, F450/F550 LIMITED TO 84 MPH.

GregKneupper · February 13, 2010

F450 and F550 will never clear a p1000. They have different emission rules than a f250 and 350. An fse and I both found this out the hard way. I just ignore the p1000 in the 450's and 550's now.

Jim Warman · February 14, 2010

On gassers, P1000 is an indication that one or more continuous monitors haven't completed.... it DOES NOT mean that codes have been cleared (though clearing codes clears all continuous monitors - which will set the P1000).

On gassers, you can access Mode 6 data. This will show you which monitors haven't completed and will offer some assistance for diagnostic purposes. If you have a persistant P1000 on a diesel, I would "guess" that one of the very few monitored conditions hasn't completed...

Flip side of the coin.... I have seen guys try to "clear" a P1000... over and over and over... ain't gonna happen

Aaron · February 15, 2010

My truck took almost 15,000km to clear the P1000 for the first time.

kevin41 · February 16, 2010

THANKS FOR ALL THE HELP AND INFO TOOK THE TRUCK OUT ON THE EXPRESSWAY TODAY MONITORED ECT EOT FRT EGRTA EGT 11 12 13 ALL PIDS NORMAL AT 75MPH ALSO GOT IT UP TO 81MPH AND HIT OVERSPEED SET A CODE BUT STILL NO POWER LOSS CUSTOMER STATES BOGGS DOWN WHEN REACHING 75MPH PULLS OVER RESTARTS AND IT IS O.K. UNTILL REACHES 75MPH I WIIL TRY TO CONFIRM ONE MORE TIME TOMORROW AND IF I CAN NOT I WILL BE GUESSING HE IS TRYING TO GO 85MPH STILL SHOWED P1000 WITH OVERSPEED CODE BUT NOW I WILL NOT BE CONCERNED WITH P1000 THANKS AGAIN FOR ALL THE HELP!!!

Jim Warman · February 16, 2010

Let's make sure the truck is at the latest calibration.. check at the throttle pedal to be sure there aren't any aftermarket piggyback things going on...

I don't know about traffic laws where you live... you got it up to 81 mph.... was it easy to get that fast or did the truck have trouble doing it? If you got a ticket going that fast would it affect you? Your licence? Your job? Your insurance?

The truck loses power at 75 mph.... I can fix this... but give me a road where I can do it legally .....

kevin41 · February 18, 2010

customer came in and took his truck drove it 70 miles at high speed truck acted up but this time set poo87 went into derate limped it back to the shop looked at freeze frame data nothing out of specs and ran high pressure fuel system test and passed going to check all fuel pressure tests to see if i can isolate which pump it needs thanks again for all the help!!!