2015 Ford Fiesta ST boost leak

[Miniman]

I have a 2015 ford fiesta st with 35k miles. About a month ago I suddenly was only getting about 5 psi of boost on my AP and had pretty much no HP. I got home and tightened up all my hosing underneath the car, this got me up to 19 psi but still not back to the 21 psi I was previously making. I decided to install a go fast bits diverter valve which got me back up to 21 psi. Unfortunately a few days ago I was getting off the highway and noticed I was back down to 5 psi once again, I went home to double check my diverter valve and the same hosing again but still no luck. Any ideas what the cause could be???

 

[tyler2687]

Maybe a wastegate issue? Being that it keeps coming back and forth I don’t think you have a boost leak. I had a lot of trouble with my old plastic diverter valve in my car so whenever you get the money and or time I’d install a Turbosmart em dual port bov that’s what I have and ever since then had no issues. Those plastic ones are garbage. And I know the stock wastegate actuators are known to leak boost past. Someone correct me if I’m wrong but I don’t think a boost leak is much in question

 

[Miniman]

Maybe a wastegate issue? Being that it keeps coming back and forth I don’t think you have a boost leak. I had a lot of trouble with my old plastic diverter valve in my car so whenever you get the money and or time I’d install a Turbosmart em dual port bov that’s what I have and ever since then had no issues. Those plastic ones are garbage. And I know the stock wastegate actuators are known to leak boost past. Someone correct me if I’m wrong but I don’t think a boost leak is much in question

I’ll definitely be investigating the Wastegate now that you mentioned that

 

[cidsamuth]

Can only tell you what happened to me ….

With stock turbo, the hot side hose blew off the IC while on the track. It almost caused me to get run over. Easy fix.

When I went S280, I lost boost, with 5lbs being the most it would muster, and I feared something catastrophic. I had checked the hoses and saw nothing. Turns out, the hose had disconnected at the throttle body, which was easy to miss because you don’t have a clear line of sight.

Your experience may vary ….