6.0 losing power under load

ktmracer21

ktmracer21

smart a$$
Joined
May 11, 2009
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Buddies 05 f550 is losing power with a load on hills. Won't spin the higher rpms It's currently only getting about 25 mph up a hill with a small box trailer no lights on though??? Seems to run rough under load but fine on flats???
 
What is fuel pressure? Any mods to the truck? Any more info? What are you trying to read codes with? Do you have a scanner where you can monitor a few things while driving it?
 
i didnt have any numbers for his truck when i posted. we were actually trying to haul when i posted. one of our friends has a snap on solas?? scanner that theyve used but never while driving it. the only known issue i know of is a leak in the exhaust pre turbo. again, truck runs fine on its own with no trailer. would seem when it has a load, its not getting fuel. just trying to get a list of ideas to run through as we start replacing parts, sensors etc. truck is not egr deleted but will be soon. thanks guys
 
all fluids are normal operating temps. he read on another forum possibly screen in tank clogged?? at this point we are going to do an egr delete as soon as he orders it, while at that time pulling the turbo apart cleaning it and i think some sensors he wantsto replace also. i still think fuel issue....but hey it isnt mine!!
 
Could be a clogged screen; it's not unusual on the models with steel fuel tanks.

There's a test port on the engine mounted fuel filter's housing, maybe you can hook up a pressure gauge to see what's going on? If it's starving for fuel those injectors are going to be hating life real soon.
 
thanks steve, id like to be able to test before i commit someone elses money to a problem.


if it were mine it woul already have been torn apart and cleaned but he has no garage,...
 
Are the fuel filters Motocraft or other ? Ford put out a TSB on aftermarket filters awhile ago.
 
I hate when people throw parts at 6.0's and then complain that they cost so much money to fix! Test, Verify, Repair...

I would start by making sure it's motorcraft/international fuel filters ONLY in there. I would then test fuel pressure like suggested at the fuel bowl. Easy to do, get a cheap gauge from harbor freight, hook it up, run it up under the hood towards the windshield and put it under the wiper so you can see it while driving. Sitting in park with it running wont tell you much. If fuel pressure checks out (usually 55-60psi, but like stated, should never fall below 45 at any point), then I would start looking at ICP readings. You want to check ICP desired, ICP actual and IPR % duty. Your ICP readings should be in PSI. Do this on stock tuning (not sure if this truck is programmed or not). You should also pull the EGR valve and inspect it, see how gummed up it is. It could be sticking and causing poor performance issues.

These are the cheap/easy steps to start with.
 
i would take the turbo apart and clean it. Maybe just throw a boost gauge in and make sure its making good boost when under a load. I would think you would get a low boost code if not but its worth a shot
 
Most likely have a plugged oil cooler. When that happens the oil temps get to high, which will cause the engine to derate. Seen it several times.
 
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