Boost issue 2021 ecoboost

[SALEEN961]

The changes made were Bambi lights, and disable double honk when the key is removed and the trick is running. Changed 3 years ago when I bought the truck.

The boost loss is increasing. Last night I data logged, then cleared adaptations and data logged again. Full boost returned for about 15 miles and started dropping off again. Drove about an hour this morning and now making about 40% boost.

Did Ford push an update that might be janky?

Should I flash the truck back to as built?

None of those changes would matter. You're not getting any codes because your truck at the very least thinks that it is producing the correct amount of boost. This could mean skewed MAPT sensors giving incorrect readings, but the most likely cause is that your desired air load and actual air load do actually match.

You need to find out what your desired air load is and if the truck is hitting that load or closely matching that number. With the key on and engine off, all of your MAPT sensors should show the same pressure/temperature readings and they should match atmospheric pressure/ ambient temperature if your truck has been sitting long enough. If everything looks good one can only assume that your truck is producing the boost pressure it is commanding.

If your truck is commanding low boost pressure, you need to diagnose why that is. Generally this is caused by real or false knock and it sounds like real knock is unlikely based on what you've already tried. Check for anything in the engine bay or around the exhaust that might be loose, hitting, or making noise. Even a minor heat shield buzz/rattle can drastically reduce commanded spark advance and boost pressure if the knock sensors hear it.

Sponsored

 

[keno199]

How is the fuel pressure? A clogged fuel filter can cause the low-end power loss.

Fuel pressure seems good.

 

[keno199]

None of those changes would matter. You're not getting any codes because your truck at the very least thinks that it is producing the correct amount of boost. This could mean skewed MAPT sensors giving incorrect readings, but the most likely cause is that your desired air load and actual air load do actually match.

You need to find out what your desired air load is and if the truck is hitting that load or closely matching that number. With the key on and engine off, all of your MAPT sensors should show the same pressure/temperature readings and they should match atmospheric pressure/ ambient temperature if your truck has been sitting long enough. If everything looks good one can only assume that your truck is producing the boost pressure it is commanding.

If your truck is commanding low boost pressure, you need to diagnose why that is. Generally this is caused by real or false knock and it sounds like real knock is unlikely based on what you've already tried. Check for anything in the engine bay or around the exhaust that might be loose, hitting, or making noise. Even a minor heat shield buzz/rattle can drastically reduce commanded spark advance and boost pressure if the knock sensors hear it.

All the sensors read 13.9 before starting and driving. When driving the boost sensor will change to the atmospheric pressure plus the boost pressure.

Could the wastegate be failing?

 

[SALEEN961]

All the sensors read 13.9 before starting and driving. When driving the boost sensor will change to the atmospheric pressure plus the boost pressure.

Could the wastegate be failing?

A failing wastegate would set a P0299 code, and wouldn't be "fixed" by resetting the adaptions

 

[keno199]

I pulled the IAT and cleaned it.

I pulled the intercooler off to check for oil and if the wastegate was sticking.

The intercooler had a very slight amount of oil on the hose from the driver side turbo. The passenger side turbo was completely dry.

I sprayed cleaner in the intercooler to see if it was holding oil, and the cleaning fluid was just slightly oil colored. Cleaned out the intercooler with compressed air.

Checked the wastegate and it moves freely. Clean off the very slight build up on the wastegate solenoid and reinstall.

Checked every hose and electrical connection. All were good. Nothing loose, no oil except for a small amount on the driver's side turbo into the intercooler.

I keep expecting a code to popup but nothing. To make it even more odd after reassembling I made a couple of trips where I turned off and parked. I had full boost on some trips and half boost on other trips. This is without resetting adaptations. It just decided when it would provide full, or half boost based on the key cycle.

Thanks to all who are sharing and trying to help me find the source. I appreciate the time you're taking to share ideas.

 

[keno199]

Update - I reset everything back to as built and still having the low boost issue. Still no codes.

Someone suggested the turbo might be failing. Seems odd at 76K miles but who knows. It will occasionally make full boost.

When I log with Forscan it seems like the requested boost matches the delivered boost. Why is it not requesting full boost?

 

[SALEEN961]

Commanded boost pressure is determined by desired load and primarily limited by the knock octane modifier and the manifold charge temp as a function of the low speed pre-ignition tables. There are other things that can limit boost pressure but they aren't relevant if you are on a stock calibration and your desired load closely matches your actual load.

Everything you have posted thus far would lead me to believe that there is absolutely nothing wrong with your turbochargers, wastegates, or BOV, and you don't have any boost leaks. A P0299 code will set if your actual boost pressure falls short of the target boost pressure by 4psi or more for more than 5 seconds.

 

[keno199]

I am still trying to find the root cause of this issue. Trying to tow uphill with half boost is nearly impossible.

I have logged many different variables and nothing is a smoking gun.

Knock - no knock recorded
Fuel - 1300+ range
Boost - require boost matches delivered boost
Turbo over or under - no
Turbo inlet - no fault
All Boost and watergate - no fault


There is one error from the active air dam. It was taken out by road debris. I did leave the actuators mounted. A code in PCM is present but no idiot light is on.

No clear adaptations does not restore full boost. But full boost will make a short random appearance.

 

[keno199]

After scanning with an SCT I found additional codes.
U0284
U0285
Both are related to the front shutters in front of the radiator and intercooler. A person on the Raptor forum had a similar issue and also had the shutter issue. Could the ECU be limiting boost based on the shutters condition?

 

[Jracing123]

I have a 2023 f150 3.5 with only 20,000 miles all stock and have the exact same issue, half boost unless I reset adaptations and sometimes it helps for a day or a week , then goes back to half, .... at a loss for what to do besides tuning it

 

[keno199]

I added a tune and the issue is gone.

 

[Jracing123]

What tune did you add

 

[keno199]

What tune did you add

5 Star

 

[DreamcastERA]

I am experiencing this same issue - and I've completed your diagnosis and more. Only difference is that I'm currently running an MPT 93 PRX tune. Despite that, I've had this tune installed for months now - and this behavior is new.

Did it ever return after your tune was installed? Or all good since then?

Sponsored