F-350 6.0 Problem

showcrop · Dec 12, 2011

I went on a couple of diesel truck forums to see what I could find out about other peoples experience with this problem, but I don't find it. The problem is that while towing a big trailer loaded to the 2006 truck's max, on a fairly long fairly steep up hill the truck will suddenly drop way off in power as if there is no more turbo boost or a severe restriction to fuel injection. At the top of the hill after cooling down I can shut it off, restart, and I get full power again. No check engine light, but instead the wrench light. I don't push the truck hard. I try to get a little run into the hills and I slowly slack off as opposed to keeping it floored and maintaining 65 all the way up. 65,000 miles, this started five months out of warrantee.

johndeerefan · Dec 12, 2011

Your truck is going into limp mode. That is what the wrench light is. It will not let the turbo make boost or engine go above a certain rpm. Mine did that once pulling a load on the interstate, but it was because of low fuel. The computer starts shutting down injectors and limiting boost if the fuel light comes on. If you had plenty of fuel, it may be the turbo made more boost than it could handle for a certain time period. I read if it makes 40 psi of boost it will go into limp mode. Kinda like a rev limiter.

Try getting out of the throttle a little earlier and watching the boost gauge. Don't let it get over 30 psi.

When you shut it off and restart it, it resets the computer.

showcrop · Dec 12, 2011

(quoted from post at 15:47:00 12/12/11) Your truck is going into limp mode. That is what the wrench light is. It will not let the turbo make boost or engine go above a certain rpm. Mine did that once pulling a load on the interstate, but it was because of low fuel. The computer starts shutting down injectors and limiting boost if the fuel light comes on. If you had plenty of fuel, it may be the turbo made more boost than it could handle for a certain time period. I read if it makes 40 psi of boost it will go into limp mode. Kinda like a rev limiter.

Try getting out of the throttle a little earlier and watching the boost gauge. Don't let it get over 30 psi.

When you shut it off and restart it, it resets the computer.

As I said above I don't push it, boost never goes over 25 lbs.

bob old iron · Dec 12, 2011

had a 03 f-350 6.0,,,it was doing about the same as you stated, i would let off pedal then floor it and release as power comes back,,,was told it could be EGR valve, around $160, in front up by thermostat, easy replace, or the IPC sensor,,,,was putting in atative from ford dealer to help lube pump and EGR valve since they lowered the sulfur rating,,, it had 106k when i traded it off, never replaced
EGR, only happened a few times, when towing/hot in summer,,was going to replace valve,,,but ending trading for single cab,,,,down sizeing from 4dr...the 6.0 i had was a good motor,,must been one of the lucky ones...

VicS · Dec 12, 2011

I don't have a 6 L Ford but, everything I have read on them says to delete the EGR valve, they say it makes the engine run hot and blow head gaskets. They also say to install ARP head studs. If I had one of these engines I would do this pdq. or trade it pdq. I am waiting for them to get super cheap. I'm then going to buy a 4 door 4X4 Lariat with a blown engine, and put a Cummins in it. The best of both worlds. LOL Vic

johndeerefan · Dec 12, 2011

With it going into limp mode, the dealer may be able to retrieve a code even though the check engine light didn't come on.

If you weren't turning over 40 lbs of boost, then the turbo wouldn't have overheated. So you should be able to eliminate that problem. It is possible that the turbo or transmission could have slightly malfunctioned on spooling up or down shifting, but not likely. Regardless, some little something is tripping the system out.

Best bet is to visit the powerstroke . org website and ask those guys. Several of their members are dealership techs. Be prepared to give a very in depth description of everything though. From what I have read it could be several things: throttle pedal, turbo, low fuel, etc..

scotc · Dec 13, 2011

Service the transmission and put a transmission temp gauge in it. The transmission could be overheating kicking it into limp mode.

You should be able to run with the big dogs at the max tow rating and not have any trouble unless it's REALLY hot out.

Brian in MI · Dec 14, 2011

check the out put voltage of the FICM, (fuel injection control module) There is a sequence to follow. look it up on powerstroke dot org. Output should be at least 45 volts, also check the ICP sensor (Injection Control Pressure) these are known to go bad, yours being an '06 it will be on the pass side valve cover, be glad it isn't a '03 cause it is under the turbo. The ICP will cause alot of driveability issues, I have replaced mine twice, issues were from low power to cruise control shutting off under 60 mph. Another thing may be a clogged oil cooler, if there is a difference of 15 degrees or more btwn coolant and oil it wil go into limp.

mkirsch · Dec 14, 2011

The 6.0s are known to have issues with the oil cooler and EGR cooler (usually together). Casting sand from the block gets in there and plugs up one or the other, causing both to overheat and fail.

Does your truck have a coolant filter? If not, you better install one soon.

Another common thing IIRC is a carboned up turbo, usually caused by "babying" the truck instead of driving it like you stole it. Requires replacement of the turbo.

Vernon in Ks · Dec 14, 2011

My 7.3 did that once. It was the air filter. Had gotten moisture from a run in heavy rain and partly blocked it. when I went to a hard pull the turbo colapsed the air tube.

showcrop · Dec 14, 2011

Thanks everyone, gives me some things to work on.

scotc · Dec 15, 2011

Didn't think of that. The only 6.0 I've run was having some problems later on, but it would hardly idle. Something about never blowing the air filter out in something like 70,000 miles.

farmallkidinPA · Dec 18, 2011

could be the motor defueling like its programmed to do.if motor gets to hot the computer will defuel and begin to shut off cylinders turning the motor into a large vaccum pump trying to cool itself off..this is taken directly from my 2002 7.3 powerstroke manual but believe it also applies to the 6.0

BrianJasper co. Ia · Dec 18, 2011

You need to find out what's in the PCM for codes. The boost gauge on the dash is not exactly what the pressure level in the intake is. It actually a calculated reading based on the exhaust back pressure sensor. Only the 03 and 04 model years latest software programming has the PCM actually look at the manifold pressure sensor and ignore the exhaust pressure sensor. The longer I think about it the more causes I can come up with. I have replaced lots of turbos for over/under boost concerns. I've yet to see one coked up causing the unison ring to stick. All of them have been due to rust. I've also seen the VGT solenoid in the turbo stick causing the same problems. A plugged exhaust pressure sensor tube can cause the boost level to jump high and then go low even though you have your foot in it. There is no exhaust temp sensor and they don't derate when they overheat. When it does derate, does the pedal go "dead" and the idle speed drop a little below normal? I've seen plenty of ICP sensors cause that.

showcrop · Dec 20, 2011

Brian, I took it yesterday to a shop that had been recommended by a friend who had been hurt very badly by a dealer. He called later on and told me his plan, which includes a part that I can't remember which is under the intake. It is not the hpop or EGR cooler. He also expects a rusty turbo. He estimates about $3K. The pedal does essentially "go dead" when it happens. I tend to blame the situation on it sitting too long in the winter. I probably would have been better off to be out plowing snow with it LOL.

400D tractorman · Dec 20, 2011

I had that same problem last year with my 2006. Sent it to the dealer before the waranty went out and problem was the turbo was rusted. You have to have the codes checked to see what the problem is that your having. Mine would run fine without the trailer hooked to it. Hope this helps. Ed

Brian Jasper co. Ia · Dec 24, 2011

I'd be looking at the data for the ICP and exhaust back pressure (EBP) before putting a turbo on. The EBP is on a piece of stainless tubing about 1 ft long attached to the front of the LH exhaust manifold. Not unusual for them to fill with carbon and restrict the tube. You can knock the carbon out of it by hammering on the tube, and running a drill bit through the fitting on the manifold.

showcrop · Dec 24, 2011

Brian, I heard back from the shop after they ran diagnostics. He says that it shows over and under boost codes and an indication that the oil temp has been running hot. I will ask him about the EBP. Any idea why so many turbos get rust on the vanes? He also said that there is a good indication that the EGR cooler has a problem.

Brian Jasper co. Ia · Dec 24, 2011

Hot oil is easy to spot. All you need to do is monitor the coolant temp and oil temp. If the oil is 50 or more degrees hotter than the coolant, the coolant side of the oil cooler is restricted. An EGR cooler and oil cooler are in your near future. Coolant flows from the block to the oil cooler first. A restricted oil cooler allows the EGR cooler to overheat. It's just a small radiator. When it gets too hot, it melts the solder and coolant goes right into the intake. In an extreme oil overheat condition the stand pipe inside the oil filter can melt. If they do the EGR cooler, make sure they do the oil cooler too. It won't last if they don't. Also have them flush the coolant with Motorcraft iron Out.
As far as the turbo goes, cast iron rusts. It's hot enough in there to keep the soot burned off most of the time. Heat and a little moisture make for rust. The replacement center section has an anti rust coating on it, seems like it's nickel. Tell them to make sure the EBP tube is not clogged.

showcrop · Dec 25, 2011

It sounds like you nailed it. He did tell me that it looks like I need a new cooler and he told me about the 50 degree difference. The estimate is just shy of $3,000, which is a lot better than the $7,000 that a friend having the same problem spent.

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