Power Loss When Engine is Warm

[mikehock]

I have an '04 F-350 with an '03 6.0 PSD all stock. I noticed what I believe is my cooling fan running constantly on the highway at speeds above 60mph even when driving without loads. Ambient air temps were less than 90f and engine temps were normal. I didn't notice any difference in power until I towed my 5th wheel trailer which weighs about 14k pounds. Towing I topped hills at 20 mph that I usually top at 60 mph while towing. Engine seems to run normal at about 1800 rpm but as soon as I step on it and truck downshifts I gain no additional power, if anything, it losses power. My first thought was fuel starvation so I changed the fuel filters but that made no difference. I'm sure that the fan running is the cause of the problem because it seems to run normal at all other times. Any help is greatly appreciated. Thanks.

[mikehock]

Also, when engine is wrapped up over 3000rpms with the fan running it makes a whistling/screaming sound which it never did before. And at those high rpms the fan sounds like it speeds up and slows down. This happens when on the throttle at those rpms and when out of the throttle like going down hills with the rpms wrapped up that high.

[SCUFFY828]

the fan will not hinder the power that much , i can see the fan coming on pulling that wieght , im gonna say you have a egr valve or turbo problem causing the low power issue , and also , its never the filters causing the problem

[mikehock]

That's good to know. Also I just topped off my coolant overflow resevour before a 1500 mile trip. I just checked it again after the trip and it has dropped from max to just below the min line. I noticed a very small amount of white smoke on cold start up, it was so minimal that it was hard to see and it goes away after idling for about a minute. Other than that I haven't noticed any smoke at all. I don't know if any of this makes any difference or not.

[iijewelry@comcast.net]

Your fan is not at all capable of slowing you down - even if it was on all the time.
Sounds like sensor problem - which one, can be hard to say.

Get a code reader. they're inexpensive, and it will likely tell you which of your sensors is malfunctioning - or something else that is off, to get you in the right direction.
( or you can use any of your friend's Superchip programmer, - they have code-readers on-board )
Sounds like it isn't fueling right - which could be a couple of things, most likely easy to mend, as soon as you have an error-code to start with.

[Manatee]

Originally Posted by mikehock

That's good to know. Also I just topped off my coolant overflow resevour before a 1500 mile trip. I just checked it again after the trip and it has dropped from max to just below the min line.

My truck drank a gallon of coolant on a trip to Florida and back. I didn't notice any smoke or leaks. Now the damn thing is in the shop getting the EGR cooler and oil cooler fixed/replaced. I hope this is not what's happening to you but the symptoms sound familiar

Good luck.

[Austin G]

Originally Posted by mikehock

makes a whistling/screaming

Wouldn't that just be the turbo? Or is it a different whistling then the turbo.

[twoicebergs]

It sounds like the turbo viens are sticking in a somewhat closed position. That would explain the high whistle and the low power under load. Until you get some codes or notice abnormal pressure changes it could be anything from sensors to turbo. You could have a cracked up-pipe causing the ecm and the FICM to provide erratic power. Taking off the turbo, checking and cleaning it is not that big of a job if you have no good leads to go on.

[mikehock]

Originally Posted by twoicebergs

It sounds like the turbo viens are sticking in a somewhat closed position. That would explain the high whistle and the low power under load. Until you get some codes or notice abnormal pressure changes it could be anything from sensors to turbo. You could have a cracked up-pipe causing the ecm and the FICM to provide erratic power. Taking off the turbo, checking and cleaning it is not that big of a job if you have no good leads to go on.

Well I took the truck in to check for codes and there were none. Other than driving over 65 mph for 20 minutes or so and towing the truck is acting normal. Ford told me that since there are no codes and it is only happening under specific conditions they can't do anything until it progresses into more of a constant problem. Don't know if this narrows it down at all.

[036.0lpowerstroke]

My '03 6.0l did this and it had blown heads but if you think that your egr is goin out on that motor you can just unplug it and it will stay closed. The only other thing that i had happen where it had powerloss and blew white smoke was when my high pressur oil pump went our and it would barely start when it was hot.