What does a stock blow off valve sound like?

[MHay]

Even stock, under low RPM with load on the engine the boost gauge will flutter. Mine does it at least twice per trip ( I live in mountainous terrain). It’s odd for sure and I can stop it by coming completely out of the throttle and then getting it to downshift.

Thanks — good to know I’m not the only one experiencing this (as long as it’s not a sign of a serious issue).

 

[MHay]

Ouch! How many miles… I hope still under warranty. At the conditions you described (10th gear, slight incline) the engine should be under a steady boost condition.

A somehow popular issue with older gen ecoboost was exhaust leak due to warped exhaust manifold that makes a squeaking sound under boost. See 1:09-1:15 from this video by Aaron Hines for what I am talking about: https://youtu.be/3r9-UT_3kyY

It only has 12,000 miles, although nearly half of those miles are from towing a 7,000 pound travel trailer.

The noise in the video is not what I’m hearing on mine. That noise sounds like it’s constant under boost (mine comes and goes) and mine is not as high pitched.

 

[MHay]

That's a reasonable assumption. The turbo spools up but the throttle plate isn't opened up enough to accept the large quantity of air. The air then pulses back through the intake to the turbos. The stock BOV may be opening but even so, it routes the air back into the intake track in front of the turbos so it gets caught in a feedback loop... If one were to ditch the stock BOV or simply disconnect the intake return pipe and cap it, then the issue may go away. Possibly? On my previous ecoboost F150, I ran a Turbosmart BOV. While the noise was cool to hear winter road grime locked it up and I would have to take it off, disassemble, and clean it at minimum once a year...

I was thinking of disconnecting the BOV return pipe to see what happens. I might give that a try this weekend. I also forgot to mention that I have an S&B intake. Maybe that’s pulling in too much air and since I don’t have a tune it’s creating an over boost situation?

 

[Team_Z]

I was thinking of disconnecting the BOV return pipe to see what happens. I might give that a try this weekend. I also forgot to mention that I have an S&B intake. Maybe that’s pulling in too much air and since I don’t have a tune it’s creating an over boost situation?

That what I thought, I put mine back to stock and it did the same.

 

[MHay]

That what I thought, I put mine back to stock and it did the same.

Have you taken it to the dealer to check it out?

 

[Team_Z]

Have you taken it to the dealer to check it out?

No not yet, I know it’s goi tkk ok be a CND issue since they won’t go out for that long of a test drive. I won’t wast my time. I’ll wait for something to fail or for it to get to a very consistent, easy to duplicate issue. For now, once it happens I let of the gas a few seconds and it goes away.