6.4 seems sluggish

Justaworktruck · Jan 7, 2018

I am new to the 6.4 but not new to diesels, I did a diy bulletproof kit on my 6.0, have a couple of big rigs, and have owned cummins and 6.5 in the past.

So I have a 2008 build nov 2007 f250xl. I purchased this truck a few weeks ago and almost immediately hooked up my camper trailer and went to florida with the family.
This truck goes like stink when matted, but seems like a bit of a dog in low load/ cruise. It does have 3.73 gears. I added an h&s tuner and set it on tow mode and it has helped liven the truck up with extra throttle... I just feel like it should have more low end grunt.

Ive used forscan to check the fuel trims, all within +/- 5%.
The target *** was 40 kpa and the actual was 140 kpa, so either one is reading actual KPA or its requesting 0 psi and I have 20 psi backpressure.

Anyone else feel the same way about the 6.4? Should I be burying my foot deeper more often?
Thanks !

ah, lastly... Is there reflash from the dealer that would help this?

Roccafellas · Jan 7, 2018

Justaworktruck said:
I am new to the 6.4 but not new to diesels, I did a diy bulletproof kit on my 6.0, have a couple of big rigs, and have owned cummins and 6.5 in the past.

So I have a 2008 build nov 2007 f250xl. I purchased this truck a few weeks ago and almost immediately hooked up my camper trailer and went to florida with the family.

This truck goes like stink when matted, but seems like a bit of a dog in low load/ cruise. It does have 3.73 gears. I added an h&s tuner and set it on tow mode and it has helped liven the truck up with extra throttle... I just feel like it should have more low end grunt.

Ive used forscan to check the fuel trims, all within +/- 5%.

The target *** was 40 kpa and the actual was 140 kpa, so either one is reading actual KPA or its requesting 0 psi and I have 20 psi backpressure.

Anyone else feel the same way about the 6.4? Should I be burying my foot deeper more often?

Thanks !

ah, lastly... Is there reflash from the dealer that would help this?

Clean your ebp

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Justaworktruck · Jan 7, 2018

Roccafellas said:
Clean your ebp

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Since I bought the truck I've been reading and completing light maintenance, one of the first things I did was clean the ebp, I did not bother to clean the tube because the ebp was so lightly sooted.
A little more info, the truck is x military (angus) and has now 44,000 kilometers.

Roccafellas · Jan 7, 2018

Justaworktruck said:
Since I bought the truck I've been reading and completing light maintenance, one of the first things I did was clean the ebp, I did not bother to clean the tube because the ebp was so lightly sooted.

A little more info, the truck is x military (angus) and has now 44,000 kilometers.

Air filter clean?
Fuel filters clean?
MAF clean?
I would clean the tube. The sensors the highest point everythings collecting at the entrance, bet the port itself at the pipe is clogged. Does it still have egr? Does it slowly build power? With only 44,000 seems unlikely that you should be having any problems WITH the proper maintenance done to the vehicle. Is there any codes? Stored codes you’d need a good scanner for pending codes.
If it was running fine before and you’ve noticed a decline in performance. Although i’d have a hard time thinking a flash could fix theoretically “what went wrong” because it was fine before.. if it was sluggish from beginning to well now and you’ve “had enough” and feel it needs more. Then yeah. If you have a monitor onboard monitor your boost and ebp and see whats going on

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Justaworktruck · Jan 8, 2018

-All filters are new, replaced fuel filter drain and cleaned out drain housing, I'll clean the maf and tube tomorrow.
-Truck is pretty much stock, has it's emissions equip.
-One one stored code for t-case, and a p1000 that's all (forscan will read stored)
-builds power quickly when the pedal is pressed further.

In the way to work tomorrow I'll monitor the ebp and map. It really just feels like it's got an on and off switch in the pedal, possibly the boost should come on sooner. I will log the wgdc and compare to map as well.

Truck has been like this since I got it, naturally I didn't notice on the test drive (wasn't trying to squeeze mileage)

I'll update tomorrow, thanks!

Roccafellas · Jan 8, 2018

Justaworktruck said:
-All filters are new, replaced fuel filter drain and cleaned out drain housing, I'll clean the maf and tube tomorrow.

-Truck is pretty much stock, has it's emissions equip.

-One one stored code for t-case, and a p1000 that's all (forscan will read stored)

-builds power quickly when the pedal is pressed further.

In the way to work tomorrow I'll monitor the ebp and map. It really just feels like it's got an on and off switch in the pedal, possibly the boost should come on sooner. I will log the wgdc and compare to map as well.

Truck has been like this since I got it, naturally I didn't notice on the test drive (wasn't trying to squeeze mileage)

I'll update tomorrow, thanks!

Okay well your probably just feeling the stock 6.4 man. Put the h&s to a 60-80horse setting see if you feel a difference, does your boost gauge on the dash work? Is it spiking full? Do u read the boost on ur h&s to see if your maintaining pressure? I won’t give a threshold because i dont know of one, i’m a beginner in this too, but if it’s max’n out the gauge and the ebp sensor isnt dirty and you dont have excessive back pressure or any other failed sensor or clogged filters.. bro it’s a stock 6.4... it’s heavy and is stock.. the 6.4’s nasty animal man.

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2008F2504x4 · Mar 16, 2018

Justaworktruck said:
-All filters are new, replaced fuel filter drain and cleaned out drain housing, I'll clean the maf and tube tomorrow.
-Truck is pretty much stock, has it's emissions equip.
-One one stored code for t-case, and a p1000 that's all (forscan will read stored)
-builds power quickly when the pedal is pressed further.

In the way to work tomorrow I'll monitor the ebp and map. It really just feels like it's got an on and off switch in the pedal, possibly the boost should come on sooner. I will log the wgdc and compare to map as well.

Truck has been like this since I got it, naturally I didn't notice on the test drive (wasn't trying to squeeze mileage)

I'll update tomorrow, thanks!

Any luck on this issue?

My truck is doing the same thing. I've had my truck for about 5 years, just started doing this a month or so ago. Just like you mentioned it's like an on and off switch. Feels like 8-10 lbs of boost and 50-75 hp difference.
My truck has a Spar*** 150 tune(also does in on the 275 tune) EGR ******, Sinister elbow, S&B Intake, 4" Dp / 5" Exhaust. Just changed all fluids and filters(This is done every 5000 miles). Installed a new motor craft EBP sensor and tube.

Thanks Shane