Having a intermittent no boost issue. Running down road usually pulling fifth wheel trailer, then notice low boost 5 to 7 psi. No check engine light, nothing. Its done it 5 or 6 times. If I hit clear code even truck has no codes set with ez-link while drive boom boost is back. Or if I pull over cycle key boost is back. I do have ppei tunes, truck is stock no mods. I have had it happen with tow tune or pull tunes out.

 

Take the tuner out.


Then run it. If there is an issue the check engine light should come on, or codes should be set.


Just because the boost is low does not always mean then is an issue, even with towing if you are at speed and there is not a power demand.


When this low boost concern is noted, what is your fuel consumption on the current mpg graph?

 

That was my thought as well.

Rob

 

I have taken tuner out and with no tuner it has done it twice. I even had it at Ford and they did there software update and it still has done it.

 

Also when I mean it has no boost I mean you hold it on the floor and it will not build more than 6 or 7 psi. One thing also is if I'm towing with engine brake on, I notice you the engine brake light on the dash goes off, and I can't turn it on and then I know truck won't build boost. cycle key and everything comes back.

 

sounds to me like a wiring harness problem.


Need to take it back in and have them go for a ride. Suggest that they get ford tech involved if they can't figure it out.


Also have them install a recorder to capture the issue.

 

Have you had any success fixing this issue?

 

Also check the clamps on the pipes for the turbo. They may be leaking. i may be wrong but anything is wort a try if it's free

 

i know this was a while back but was this issue resolved? If so what was the cause. I have a 2015 doing exact same thing. Stock no tuner 50,000 miles. Been monitoring it for about 5 months now. Cycle key and problem goes away. Any help would be appreciated.

 

You have a issue with your tune. I would call the guy who did your tune and let them know what it's doing. Sounds like there is something wrong with your hand held tuner. If you return truck to stock and it does the same thing. Interesting thing is you shut off the truck and everything is fixed.

 

My 2011 F450 is doing this. I’m also thinking it’s a wiring/computer problem since it is intermittent and seemingly at random times.

but how the hell do you track down a problem like that?

 

I started a new thread and finally found someone else having my issue. Mine is low boost. Truck will boost up to about 18 psi max. Builds slow on take off. Stop, turn truck off about half the time it’s there, half the time it goes away. 85000 miles. Good maint, all Ford filters. Never tuned. Never even been under the hood except maint. Any resolve here????

 

In your case As soon as this happens to your truck I would take it to a dealer and have them take a look at it. Intermittent problems are hard to track down. The dealer has the tools to diagnose the problem. It may cost a buck or 2 but you could chase a problem like this down and never find the problem. The dealer can't fix it if the truck isn't doing it. Dont shut the truck off because that might fix the problem just leave it running. Let them drive it and go with them and let them know what you see.

 

Mine was cured this weekend by a DEF tank heater. Cleared the code she runs like a scalded ape again. Before changing the heater I would start the truck. Let it idle. Clear the “Pending” heater code and truck would run fine even though the permanent heater code was still there. It apparently checks randomly because it did it a few times in the middle of driving. It derated itself, check codes, the pending heater code is back, clear code- truck runs great. I did this many times to make sure it was the problem. I suppose the engineers do this to irritate you enough to get it fixed. Because it’s 100 degrees in Texas right now. I also think it’s defueling when it does this, which causes lower boost. I don’t think it’s a low boost issue on its own. It’s done this randomly long before the CEL came on. I didn’t have a dongle back then but suspect something was happening and I just didn’t know it. Without a cel I would recommend starting with a defuel problem.

 

VGT Solenoid/ or connector.
mine was the connector.
kept thinking the turbo was stuck open. but the solenoid that controls it was actually unplugged. no boost, 1 or 2 lbs, black smoke, no wastegate. now power, kept happening every couple months…. no codes (fully deleted, egr,pdf w/ h&s)

i just had the same problem. turns out the connector was bad, one of the keeper ears broke and caused the plug to barely connect.

was having intermediate boost.. then fixes itself…then no boost…randomly (usually after running 85 for a couple hours it would happen)

finally the connector came off completely.

can’t see the plug-in. but no need to pull the manifold. just a mirror and a light you can replace the pigtail and plug it in.

hope this helps!