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Discussion Starter · #1 ·
I noticed last night on the way home that if I'm in 5th gear around 3k RMP and I put the accelerator to the floor the car starts to accelerate but it makes a sound like it's intermittently venting boost and there's subtle lags in acceleration. Is this just the ECU controlling boost levels or is there something weird going on?
 

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Really tough to tell...i've never experienced anything like that...I've heard of people say they had some of the piping couplings a bit loose from the factory and needed tightening up to contain all the boost.
 

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I noticed last night on the way home that if I'm in 5th gear around 3k RMP and I put the accelerator to the floor the car starts to accelerate but it makes a sound like it's intermittently venting boost and there's subtle lags in acceleration. Is this just the ECU controlling boost levels or is there something weird going on?
21psi is a lot of boost so perhaps something is loose? I would check every coupler on your charge pipes and see if something is loose. Most cars have a rattle snake sound that is heard in the intake from the stock boost controller or wastegate but this doesn't sound like that.

Just check your charge pipes and if it doesn't change take a video of it and maybe that will help. Either way, if it isn't loose and doesn't go away, pay a visit to the dealer. You are paying for your warranty. Might as well get use out of it.
 

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Discussion Starter · #4 · (Edited)
Thanks for the responses.

If I go from a standing start and accelerate quickly it's not there. It's only full throttle roll on from partial throttle. If it were a leak I'd think it would be just as (if not more) present from a standing start. But even full throttle 1-4 from a standing start it's not there. But it's very apparently from partial throttle to full throttle (so far) in 4th, 5th, and 6th (haven't tried 1-3).
 

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its likely due to cold weather. If it sounds like this


(towards the redline in second you can hear a chu chu chu)

its the bypass integrated into the compressor venting excess boost due to reaching a load target.

More apt to happen in cold weather. Nothing to worry about
 

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Discussion Starter · #6 ·
its likely due to cold weather. If it sounds like this

(towards the redline in second you can hear a chu chu chu)

its the bypass integrated into the compressor venting excess boost due to reaching a load target.

More apt to happen in cold weather. Nothing to worry about
It's hard to hear but I figured it was that and also reasoned the cold snap we are feeling was at least partially to blame. Thanks for the peace of mind.
 

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I noticed last night on the way home that if I'm in 5th gear around 3k RMP and I put the accelerator to the floor the car starts to accelerate but it makes a sound like it's intermittently venting boost and there's subtle lags in acceleration. Is this just the ECU controlling boost levels or is there something weird going on?
I just encountered something similar to this last night. At WOT seemed a little weak at times?.. Also heard a venting sound as he described, but I've never heard this particular one before. I am also running an ultra guage and was monitoring the boost and it would only hit 14psi every time I entered boost. It was also really cold around 12F at the time. Any suggestions?
 

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I find on partial throttle you can hear it venting, but on full throttle it will only do it when I change gears, a loud Woosh sound.
 

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I've noticed this as well and only really seems to happen in 4th and above dependant on rpm and load. Usually seems to happen more when rpms are fairly low. It does "feel weaker" when this happens though.
 

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My particular power issue seems to have gotten worse. It doesn't put me back in my seat anymore, and feels like i'm not really getting max boost till around 4K rpm now. Service appointment set, hopefully everything is fine......has anyone else noticed lots of noise from the front drivers side? Maybe its just electric steering components or something, but on the shift from 1 to 2 I get clicks, and all sorts of noise. I also have a howl from the same area when the RPMs are around 1500 or so even with the clutch pedal depressed. I don't know.....weird.
 

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My particular power issue seems to have gotten worse. It doesn't put me back in my seat anymore, and feels like i'm not really getting max boost till around 4K rpm now. Service appointment set, hopefully everything is fine......has anyone else noticed lots of noise from the front drivers side? Maybe its just electric steering components or something, but on the shift from 1 to 2 I get clicks, and all sorts of noise. I also have a howl from the same area when the RPMs are around 1500 or so even with the clutch pedal depressed. I don't know.....weird.

I'm thinking we got leaks somewhere. My car hasn't gotten worse also, it just seems down on power and I hit 14-16psi at the most. I'll probably have to take mine in also judging by this thread lol. Take a look at it if you have already read..

http://www.fiestast.org/forum/showthread.php?t=604


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There is around 12 hose clamps between the turbo outlet and the throttle body, anyone can leak boost pressure. I have travelled 2000kms in my ST and tightened the clamps 2 times already.
 

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I tightened 4-5 mine... some were very loose.
 

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Are there not better clamps out there than what they are using? I am pretty sure there are....

 

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Just found this picture of the MRT Fiesta ST with the Cobb FMIC, those clamps!
Ummm, and look at the charge pipe diameter, holy 3" piping batman!!!! LOL :p
 

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My particular power issue seems to have gotten worse. It doesn't put me back in my seat anymore, and feels like i'm not really getting max boost till around 4K rpm now. Service appointment set, hopefully everything is fine......has anyone else noticed lots of noise from the front drivers side? Maybe its just electric steering components or something, but on the shift from 1 to 2 I get clicks, and all sorts of noise. I also have a howl from the same area when the RPMs are around 1500 or so even with the clutch pedal depressed. I don't know.....weird.
I know this is an old post but I am curious as to what the outcome was with the noises and such. Was there loose clamps or was it something else?? Thanks!
 
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