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Discussion Starter · #1 · (Edited)
Driving down the road and all of a sudden the truck started running awful. Wouldnt build boost and was beyond slow. Truck was tuned but rarely run the tune. Turned on my monitor and was only building a pound of boost. To this day im only showing 0.7 pounds of boost. I have the eta mod done and at low speeds i can hear a little whistle with the let off.
Anybody been through something similar?

Edit : I have taken off the BOV and checked for tears but didnt notice anything. The trucks a 2016 3.5
 

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2015 Ford F-150 Lariat Screw 5.5' | 3.5 Eco | 4x4 3.55 Max Tow | 33's, Tuned by BoostKing
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First check to see if you have stored any DTC / trouble codes on the computer. If you have the device for your custom tunes, use it to read, then clear codes and see if things go back to normal.

If not, codes will be helpful in further diagnosis. Could be an under boost code from a leaky connection somewhere.

Sounds a bit like limp mode, where truck limits boost and is a dog. Have had that a few times with no visual on the dash.
 

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Discussion Starter · #5 ·
First check to see if you have stored any DTC / trouble codes on the computer. If you have the device for your custom tunes, use it to read, then clear codes and see if things go back to normal.

If not, codes will be helpful in further diagnosis. Could be an under boost code from a leaky connection somewhere.

Sounds a bit like limp mode, where truck limits boost and is a dog. Have had that a few times with no visual on the dash.
I checked for codes and got these two.

P051B
CRANKCASE PRESSURE SENSOR CIRCUIT RANGE/PERFORMANCE

P05AE
ACTIVE GRILLE AIR SHUTTER B PERFORMANCE/STUCK OFF
 

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2015 Ford F-150 Lariat Screw 5.5' | 3.5 Eco | 4x4 3.55 Max Tow | 33's, Tuned by BoostKing
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Vacuum line unplugged somewhere? PCV valve is good suggestion.
The shutter error seems coincidental; odd it would cause drivability issues?
Clearing the codes to see if it drives better could reveal if the failure to build boost is due to a problem itself (BOV, vacuum, etc.), or due to there simply being a problem (limp mode); if that makes any sense.
 

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Discussion Starter · #9 ·
Make sure the PCV valve didn’t fall apart. Tho that code is effected by the smallest of changes, doesn’t hurt to check.

Shutter B are the intercooler shutters. Could be stuck closed, and/or motor has failed. Maybe even unplugged?
Ill try checking that later when I get off, would you happen to have a reference picture of the pcv valve?
 

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Discussion Starter · #10 ·
Vacuum line unplugged somewhere? PCV valve is good suggestion.
The shutter error seems coincidental; odd it would cause drivability issues?
Clearing the codes to see if it drives better could reveal if the failure to build boost is due to a problem itself (BOV, vacuum, etc.), or due to there simply being a problem (limp mode); if that makes any sense.
I’ve tried checking lines for leaks, not tight, etc, havent seen anything(also not 100% on what im looking at and sure I missed some stuff). I’ll try clearing the codes and see what happens
 

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Discussion Starter · #13 ·
Crawled under the truck, in the hood, dont see any pipes or anything loose🙄 trucks been running stock and was getting to 0.7 lb boost, put my 89 tune on and was building 1.3 lb boost..
 

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My 2014 had this happen, but gave me a message "Reducing power to keep engine from overheating." While this was covered in the forum for vehicles towing, mine occured with normal operation. My mechanic pressure tested and found a leak in one of the hoses to the left turbo. They are replacing the hose and then will retest. It was a slow leak he said, but did evaporate considerable coolant. Keeping my fingers crossed. Good thing these things slow things down to keep from more significant damage like broken rods, seized pistons.
 

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Discussion Starter · #16 ·
My 2014 had this happen, but gave me a message "Reducing power to keep engine from overheating." While this was covered in the forum for vehicles towing, mine occured with normal operation. My mechanic pressure tested and found a leak in one of the hoses to the left turbo. They are replacing the hose and then will retest. It was a slow leak he said, but did evaporate considerable coolant. Keeping my fingers crossed. Good thing these things slow things down to keep from more significant damage like broken rods, seized pistons.
have you had any luck?
 

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Discussion Starter · #17 ·
Noticed recently the turbos almost sound shut, i can hear boost building(still only 1 pound) but its a more high pitch sound like its trying to build all this pressure but cant get through? Almost like somethings squeezed. Not sure if that makes any sense.
 
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