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Discussion Starter #1 (Edited)
Hey all,

My sister has a '14 SFE EcoBoost w/ only 32k miles. As a car enthusiast, I personally recommended this car when Ford was bringing over the 1.0L turbo back in 2013. Turbo, hatchback, manual, 40+mpg, all seemed to make sense.

So far the car has been doing great until yesterday. While running errands, she briefly stopped to pickup something. Upon starting the car again, the car idled differently and she knew something was wrong. Driving home, the car was extremely slow and truly felt like a 1.0L without the aid of a turbocharger. No check engine light tripped, so I bet the car thinks everything is fine. :eek:

Being 1700 miles away, I can't physically diagnose the Fiesta, so I told her to take a detailed video of the engine bay and a few free revs to try and capture the sound.


Last oil change was less than 3k miles ago and the dipstick is still showing 3/4ths.

My guess is a boost leak somewhere or a stuck wastegate.

The car is a year out of powertrain warranty, so any other help / ideas would be appreciated!
 

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The wastegate is vacuum actuated. It requires vacuum (cam driven vacuum pump) in order for it to remain closed to provide boost. The brake booster is also driven from this same pump.

Do the brakes feel different? If so, there could be a leak somewhere in the vacuum system. I wouldn't rule out a small rip in the wastegate diaphragm. That one is easy to test. With the engine off, disconnect the hose from the wastegate and attach a mighty vac to the wastegate. Pulling vacuum should close the wastegate (you'll see the arm/rod move).


If there's no leaks in the system, the solenoid that controls how much vacuum the wastegate sees could be bad. It's somewhere on the back of the engine if I recall.

There are other things that could command the wastegate to remain open. Overboost or brake system faults (like resting your foot on the brake and accelerator at the same time), but those almost always trigger a code, and reset after every engine restart.


If she keeps her foot down on the throttle in a high gear for long enough, an underboost style fault should trip. I think it takes something like 10-15 seconds though.

Anyway just some ideas.



Yeah, it's really slow without boost. All 70whp worth. I have a button that disables my wastegate intentionally to prevent the car from going into boost. I mostly use it to prevent from going into boost before operating temps are reached.
 

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Discussion Starter #3
In a rare turn of events, my sis brought her Fiesta to a local mechanic...

Turns out someone tried to steal her catalytic converter while she was at work. :mad:

There are saw marks around the mid pipe resonator / secondary cat(?), I guess the thief gave up when he realized the primary cat was more upstream. The exhaust pipe broke shortly after the attempt which led to power loss + noise.

The wastegate is vacuum actuated...
I mostly use it to prevent from going into boost before operating temps are reached.
Thanks for all your insight! I remember seeing your post about having an "eco" button. That thread allowed me to try and diagnose my sis' issue remotely.
 
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