Boost flutter

[DSMtuned]

My mods are in my signature.

My truck has boost flutter in high gears at low RPM.  The boost will spike and then fall by about 5psi.  It will do this rapidly until I downshift or apply more throttle.

This effect was present when stock, but only when really lugging the truck when locked in a high gear.  With a tune it happens more frequently and without full throttle.  I just installed a Full Race catted downpipe and now the effect is very pronounced. 

It seems like the wastegate has a weak spring and is easily blown open with aggressive boost curves and higher than stock boost.  Also the decreased backpressure of the new downpipe didn't help things.  Sound about right, or is there a different explanation?

What about a fix?

Thanks for your brainstorming.

[AJP turbo]

What elevation do you live at?

[ZSHO]

I noticed you have a 2012 F150!!  Did you ever have your intercooler checked out in form of an updated TSB followed by a reflash of the PCM.?  Z
I would also check your boost solenoid and waste-gate hoses to make sure the hoses are not loose or split.
Any DTC codes set ? How many miles on her?
DSMtuned due setup an intro by following the below link and Welcome,thanks. Z
 
http://www.ecoboostperformanceforum.com/index.php/board,14.0.html

[SHOdded]

Some clues may lie in these threads:
http://www.ecoboostperformanceforum.com/index.php/topic,4756
http://www.ecoboostperformanceforum.com/index.php/topic,4958

[DSMtuned]

What elevation do you live at?

I'm at 6300'.  I asked 5 Star to correct for altitude

[DSMtuned]

I noticed you have a 2012 F150!!  Did you ever have your intercooler checked out in form of an updated TSB followed by a reflash of the PCM.?  Z
I would also check your boost solenoid and waste-gate hoses to make sure the hoses are not loose or split.
Any DTC codes set ? How many miles on her?
DSMtuned due setup an intro by following the below link and Welcome,thanks. Z
 
http://www.ecoboostperformanceforum.com/index.php/board,14.0.html

I bought my truck with 54k mile on it and it has 63k now.  It had the cam phaser and chain TSB done, but I'm not sure about the intercooler TSB.  How could I find this out?

No DTCs at this time.  I've checked all my vacuum, but I'll go through those again to be sure.

[ZSHO]

Here are a couple of links for ya,hope it helps any. Z
http://www.ifama.net/documents/fordservicemessagesandbulletins-may-sept2013.pdf
Under truck lines

BCM   6555   – 2011 -2013-F-150 3.5L GTDI– Identifying latest Level Charge   Air Cooler (CAC) By Service/   
Engineering Part Numbers
2011-2013 F-150 3.5L Gas Turbo Direct Injected (GTDI) latest level CAC   canbe identified   by inspecting the white   
part number label located on the   driver side   end tank of the CAC.
Service part BL3Z-6K775-B   (Engineering part   
BL34-9L440-AE) is applicable to 2011– 2012 model years only and Service   part   DL3Z-6K775-B (Engineering part
DL34-9L440-AC/AD) is applicable to 2013 model year only.   

Recalls & TSB
http://recalltsb.com/2012/FORD/F-150

CAC (Intercooler)
ftp://

[SHOdded]

We have some f150 recall/tsb stuff on here, but this is a very handy site:
http://www.revbase.com/BBBMotor/Tsb/Results?Year=2012&Make=54&Model=666

[DSMtuned]

Thanks for all the links!  Those should be helpful.

It looks like my intercooler is one letter off from the problem ones, so hopefully it's ok. 

My logs don't indicate any misfires. 

Attached is a log from today.  It looks like boost, load, and throttle position are all bouncing around.  Wastegate percentage also seems less stable than I would expect.  Any ideas?  I sure appreciate it! 

[DSMtuned]

Here's a video of the issue. 

Just for reiteration, I just installed a catted downpipe.  This boost flutter happens at moderate throttle, low RPMs, and with moderate load.  It happens with the stock calibration, my last revision custom tune, and with the updated custom tune to correct for the downpipe.  Attached is a log.  You can see it happens 3x a second.

I noticed this with the stock calibration prior to the downpipe when locked in 6th gear going 65 in the mountains.  It happened occasionally with my custom tunes, but never this dramatic and only when really lugging.  Now it occurs with all of my prior custom tunes and with the updated ones. 

It sounds like the BOVs are dumping boost.  If you look at the logs, the throttle angle and the wastegate increase just after the boost deceases, mostly.

Here are my working theories:
1) BOV solenoids (one or both) are failing.  2012 F-150 here, so mechanical BOVs.
2) Wastegate solenoid is failing.  You can see the WG percentage sometimes falls when the boost falls, but not always, so I'm thinking the sharp increase is more of a compensation.
3) Wastegates are mechanically being blown open due to weak springs and the decreased backpressure with the new high flow downpipe made this worse.

Not too long ago I cleaned my MAP sensors and placed clamps on all my vacuum hoses.  I also checked for any cracked lines or connections. 

I still can't put my finger on why the throttle angle would change with the oscillation of boost like it does. 

Any ideas here?  I want to be excited about my new downpipe, but I'm really feeling kind of bummed.

[AJP turbo]

Did you have 5 star review the logs?

[AJP turbo]

1) BOV solenoids (one or both) are failing.  2012 F-150 here, so mechanical BOVs.
2) Wastegate solenoid is failing.  You can see the WG percentage sometimes falls when the boost falls, but not always, so I'm thinking the sharp increase is more of a compensation.
3) Wastegates are mechanically being blown open due to weak springs and the decreased backpressure with the new high flow downpipe made this worse.



I still can't put my finger on why the throttle angle would change with the oscillation of boost like it does. 

I don't think your BOV's are mechanical. Everything is electronically controlled at some point with these.
The downpipes shouldn't have made that dramatic effect on back pressure to the point it would manifest itself in other ways.

You really need to throw out conventional wisdom with the engine management with ecoboost. The throttle will do what it needs to in order to achieve the boost that is being commanded. Have you logged "desired TIP"?

The throttle pedal and throttle blade relationship really mean nothing that you think it does anymore....Your pedal position is simply a torque request and then gets processed in a complex algorithm which gets turned into an airflow request which then gets turned into a TIP(throttle inlet pressure) and the throttle will do what it wants to maintain the same TIP in the intake manifold.

I also think your elevation is playing a factor

[lamrith]

1) BOV solenoids (one or both) are failing.  2012 F-150 here, so mechanical BOVs.
2) Wastegate solenoid is failing.  You can see the WG percentage sometimes falls when the boost falls, but not always, so I'm thinking the sharp increase is more of a compensation.
3) Wastegates are mechanically being blown open due to weak springs and the decreased backpressure with the new high flow downpipe made this worse.



I still can't put my finger on why the throttle angle would change with the oscillation of boost like it does. 

I don't think your BOV's are mechanical. Everything is electronically controlled at some point with these.
The downpipes shouldn't have made that dramatic effect on back pressure to the point it would manifest itself in other ways.

You really need to throw out conventional wisdom with the engine management with ecoboost. The throttle will do what it needs to in order to achieve the boost that is being commanded. Have you logged "desired TIP"?

The throttle pedal and throttle blade relationship really mean nothing that you think it does anymore....Your pedal position is simply a torque request and then gets processed in a complex algorithm which gets turned into an airflow request which then gets turned into a TIP(throttle inlet pressure) and the throttle will do what it wants to maintain the same TIP in the intake manifold.

I also think your elevation is playing a factor

WOW,
Great breakdown.  I am not having problems at all, but that writeup is great info to help understand a little bit on how this newer system works.

[Colorado-SHOBro]

What elevation do you live at?

I'm at 6300'.  I asked 5 Star to correct for altitude

Where do you live?

Don't underestimate the impact of altitude on a tune with these ecoboosts. Me and AJP turbo had to iron out a good few details when tuning my car and he was willing and able to put in the effort to see exactly what worked.  It's hard for me to believe any vendor out there has enough experience tuning at altitude to get it right on the 1st couple of tunes. If i were you, bugging 5 star to look at the logs and troubleshoot would be the 1st step.

[DSMtuned]

Did you have 5 star review the logs?

I sent them the logs on Friday afternoon.  I'll probably call them tomorrow.

Attached is the full log.  It does have TIP boost and TIP boost dsd.