I have a 2009 6.4 Super Duty I have owned since new. It has 188,000 KM and has worked pretty hard at times during it's life. At 96,000 km I installed a Banks 6 Gun Bundle and was happy with the modification. It certainly improved the mileage and gave it a bit more power. I did not want to roll coal so I kept the DPF as much as it's a royal pain. The truck does not make oil and I always run it on the highway when the DPF decides to regen which is about once a fill up. Of course I get a puff of blue smoke when the regen process begins. It idles like a champ and runs very well overall. I use a fuel additive at every fill.

A few months ago my mileage suddenly got quite bad (about 30% higher) and I'm having a difficult time determining what the issue is. Currently there are no codes on my tuner as I have deleted them expecting them to show again if the problem persisted. They have not. The codes I've had are:
P0488 EGR Throttle control circuit performance
P2002 Diesel Particulate filter below threshold
Both front wheels turn freely without and rough sounds that would indicate brinelled bearings.
All the u-joints and steady bearing appear to be tight and in good condition.
I've had two pinion seals replaced from new and the service tech suggested my rear differential may need rebuilding. I do experience a whine above 55 mph with my foot in it that disappears under deceleration. However this same tech replaced an idler tension pulley to eliminate a drive belt squeal which persisted until I had a new drive belt installed during my next visit.
Recently I have noted a slight shudder when turning sharply from a stop.

Any help or suggestions would be greatly appreciated as I expect to keep this truck for some time. The new ones are $100,000 here now and I need a truck that will actually do some work.

Greg

 

 

theres a video on youtube about removing the EBP sensor and poking a coat hanger into the hole to clear out carbon build up.

the reason I am suggesting that is because you say you regen about once every thankful....that means you are probally in "fault" mode....meaning...if regens dont occur based on reaching a predetermined back pressure threashold...the engine will regen a a fix mileage interval.

so if your EBP sensor is caked over with carbon... your DPF is likely to be running full most of the time...the added back pressure from a full DPF will screw up MPG

air entrampment will reduce MPG as well

work rocker tips

bent push rods

clogged filters

etc.

here's some info from another link about additives and mpg. I use opti lube seasonal blend

NO ADDITIVE
Highway Average 14.6 mpg
City Average 13.7 mpg
Overall Average 14.1 mpg
TWO-STROKE PRE-MIX
Best Highway (one tank) 16.3 mpg
Best City (one tank) 14.9 mpg
Highway Average 15.6 mpg
City Average 14.6 mpg
OPTI-LUBE XPD
Best Highway (one tank) 17.4 mpg
Best City (one tank) 15.7 mpg
Highway Average 16.1 mpg
City Average 14.4 mpg
FPPF 8+ CETANE IMPROVER
Best Highway (one tank) 17.3 mpg
Best City (one tank) 15.0 mpg
Highway Average 16.1 mpg
City Average 14.9 mpg

 

I'm with all of the above advise.

Big question is, do they do testing in Canada on emissions?

If not, make a boat anchor out of that DPF and tune it accordingly.

Denny

 

Some provinces are pretty sticky about emissions. As I said I have no desire to look coal powered. Banks claims there system will not work with the DPF removed.
The best mileage I have recorded was 11 litres per 100 km which translates to 21.4 miles to the US gallon at 55 mph. That was just last summer.
Thanks for the tip on the EBP valve. My mileage loss was sudden and occurred at just about the right mileage total from what I saw on YouTube. Fortunately it looks like the 6.4 pipe is more accessible than other engines. After a pot of coffee I think I'll tackle it. It's still pretty fresh this time of year for outdoor mechanics but the worst is over. It was a very cold winter. I have a Land Rover on jack stands in the garage right now so that isn't an option.

It could very well be a pinion whine that I'm experiencing. I hauled 9 loads from Calgary to Thunder Bay two years ago when we moved here. That's 17 one way trips in three months. I put 40,000 km (25,000 miles) on the truck during that time pulling everything from a 35' 5th wheel to a 26' enclosed trailer. This truck never let me down. It has been absolutely reliable from the first day. I can't say that about any of the GM vehicles I've had.

 

fritz has excellent points. I recently replaced both the MAP and EBP sensors and cleaned out the EBP port...top and bottom of tube. Replaced both sensors for good measure.

I agree with Denny on the DPF removal if you can get away with it. The stress the regen process puts on your engine, especially the rear 7&8 cylinders, isn't worth it. You'd also note an increase in fuel economy if you can keep your foot out of it. I get about 16mph city with a 12 mile stretch to work(I jump right on the freeway to and from work...so not a lot of stop and go...though its a rather short drive...but its highway miles). Also...I wouldn't worry about rolling coal...unless you have a heavy foot. I run a mild tune, fuel treatment, and a light foot...I have to think to try to roll coal.

 

 

Pulled the tube and sensor this morning. A challenging task. 5/8" wrench gymnastics. Pipe has very little carbon build up. Ran a coat hanger into the exhaust manifold. Inside the sensor I can see copper colored material. That's not to say the sensor isn't the problem but it's a darn sight easier to change than the tube. I'll see later when I hit the expressway if I did any good.

Greg

 

After two days of driving the same route as before my mileage has stabilized at 22 litres per 100 km. A bit higher than the 19-21 I expect for that kind of driving. Down from 26/27 l/100km. What's puzzling about this to me is the truck has not entered a regen cycle. If the DPF was running clean what good could cleaning the pipe have done?