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Car randomly loses boost for a few days

Messages
8
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2
Location
Lumberton
#1
Hey everyone. I purchased my 2014 FiST about 5 months ago. It already had some upgrades, when I got the car. (Injen intake, mbrp exhaust with downpipe, and a Cobb Stage 3 tuner covers most of the motor stuff) After about 2 months, the car just randomly wouldn't boost. It was fine one minute and then boom, not OK. It was only getting to about 5lb of boost. Well after a couple days, it just went back to normal. I don't really know too much about turbos (I've always been a Jeep guy) but what made the most sense to me was a sticking waste gate. Well after it started working properly again, that lasted about a month and then it did it again. So now, it seems to happen once every few weeks. It will last a couple days and then seems to go back to working (back to 24ish lb of boost)

I have checked all the hoses and lines and they are tight. Like I said, I dont know much about this, but logic has me thinking that the waste gate is sticking. I guess I am going to pull the turbo off and take a look at it. Anything I should watch for? Tips on removing the turbo? Things to look for when its out?

Another thing that the car is doing (may be related is why I mention it), it has the surging issue that I have read about. Seems this happens often on these cars? When at a low RPM, if I step on it and the turbo really has to build a lot of boost I get the surge and hear the psst, psst, psst, until it gets into a higher RPM and the engine isnt bogged down anymore.

Let me know if anyone has any ideas or solutions! Thanks
 


Messages
309
Likes
123
Location
Brooklyn
#2
Hey everyone. I purchased my 2014 FiST about 5 months ago. It already had some upgrades, when I got the car. (Injen intake, mbrp exhaust with downpipe, and a Cobb Stage 3 tuner covers most of the motor stuff) After about 2 months, the car just randomly wouldn't boost. It was fine one minute and then boom, not OK. It was only getting to about 5lb of boost. Well after a couple days, it just went back to normal. I don't really know too much about turbos (I've always been a Jeep guy) but what made the most sense to me was a sticking waste gate. Well after it started working properly again, that lasted about a month and then it did it again. So now, it seems to happen once every few weeks. It will last a couple days and then seems to go back to working (back to 24ish lb of boost)

I have checked all the hoses and lines and they are tight. Like I said, I dont know much about this, but logic has me thinking that the waste gate is sticking. I guess I am going to pull the turbo off and take a look at it. Anything I should watch for? Tips on removing the turbo? Things to look for when its out?

Another thing that the car is doing (may be related is why I mention it), it has the surging issue that I have read about. Seems this happens often on these cars? When at a low RPM, if I step on it and the turbo really has to build a lot of boost I get the surge and hear the psst, psst, psst, until it gets into a higher RPM and the engine isnt bogged down anymore.

Let me know if anyone has any ideas or solutions! Thanks
Possible inadvertent map switching. Did you play with cruise control when it happens?




DEss
 


Messages
475
Likes
227
Location
Dublin, OH
#3
Could be a malfunctioning diverter valve or a sticking piston if you have a GFB valve.
 


OP
W
Messages
8
Likes
2
Location
Lumberton
Thread Starter #4
Possible inadvertent map switching. Did you play with cruise control when it happens?




DEss
I am assuming you are wanting to know if it does it with cruise on and off? I do use cruise for about 50 miles every day. Have not noticed anything strange.
 


OP
W
Messages
8
Likes
2
Location
Lumberton
Thread Starter #5
Could be a malfunctioning diverter valve or a sticking piston if you have a GFB valve.
Thanks for the reply. I will do some reading on this. I have no idea what that is or if I have a GFB valve lol. The only modifications to the car are the ones listed in the OP, so everything else would be factory equipment. Any other info or things to check would be appreciated! Thanks again
 


Messages
182
Likes
54
Location
Gatineau
#6
Being stuck at 5PSI really sounds like being on the eco map as, if I remember right, it limits boost to 5PSI.

With cruise control off, press the cancel button. The RPM gauge will go to either 1 or 2 depending on the map it's on. 1 being power and 2 being eco (that's for the OTS Cobb map, different for other tunes). Switch between them with cruise up and cruise down, you'll see the needle go between 1 and 2 doing that. You have only a few seconds after pressing cancel to switch the maps, but you can do it as often as you want.

You can also check and switch them in the AP.

I have not got any surge on my 2014 sonce I've had it for a year, but I built it up to stage 2 from stock myself, so who knows what your previous owner did that might cause that.

Sent from my ONEPLUS A3000 using Tapatalk
 


OP
W
Messages
8
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2
Location
Lumberton
Thread Starter #7
Being stuck at 5PSI really sounds like being on the eco map as, if I remember right, it limits boost to 5PSI.

With cruise control off, press the cancel button. The RPM gauge will go to either 1 or 2 depending on the map it's on. 1 being power and 2 being eco (that's for the OTS Cobb map, different for other tunes). Switch between them with cruise up and cruise down, you'll see the needle go between 1 and 2 doing that. You have only a few seconds after pressing cancel to switch the maps, but you can do it as often as you want.

You can also check and switch them in the AP.

I have not got any surge on my 2014 sonce I've had it for a year, but I built it up to stage 2 from stock myself, so who knows what your previous owner did that might cause that.

Sent from my ONEPLUS A3000 using Tapatalk
Thanks! Will mess with this in the morning.
 


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528
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Location
JeffCo
#8
...With cruise control off, press the cancel button. ...
I agree with everything you said, except I believe the button to push is Resume, not Cancel. (That's why it's so easy to accidentally switch them when you think you have cruise set and try to resume but you haven't set it yet - who even uses cancel, right??) Hold down Resume and the tach should sweep to the number of the map slot.

[rockon]
 


Messages
182
Likes
54
Location
Gatineau
#9
I believe we are both right. The button is can/res. Press on it and the needle goes for 1 or 2. Press SET+ or SET- to change maps.

It miggt work by holding the can/res buttons, but it works for sure with the can/res button by just tapping it.

And directly from Cobb:
https://cobbtuning.zendesk.com/hc/e...eatures-How-To-Map-Switching-on-Ford-Vehicles


Sent from my ONEPLUS A3000 using Tapatalk
 


Messages
475
Likes
227
Location
Dublin, OH
#10
Being stuck at 5PSI really sounds like being on the eco map as, if I remember right, it limits boost to 5PSI.
I have a Stratified tune with 2 eco slots (93 and E30) and the standard Stratified eco tunes are limited to 15 psi of boost, not 5 psi. The Cobb tune notes written by Will Trang state that economy boost is limited to 8 psi, which is a lot less than my Stratified tunes, but still not as low as the 5 PSI the OP is seeing. Of course, you can have the tune custom altered to limit boost to 5 psi, and other tuners might do other things.

Also, the "flutter" reported by the OP is an issue that GFB valve users have reported here, particularly when the piston builds up some crud. Cleaning the piston and lubricating it with a very coating of lightweight synthetic oil has been reported to fix it. That's why it might be a good idea to take a look and see if the OEM diverter valve has been changed.
 


Messages
182
Likes
54
Location
Gatineau
#11
I have a Stratified tune with 2 eco slots (93 and E30) and the standard Stratified eco tunes are limited to 15 psi of boost, not 5 psi. The Cobb tune notes written by Will Trang state that economy boost is limited to 8 psi, which is a lot less than my Stratified tunes, but still not as low as the 5 PSI the OP is seeing. Of course, you can have the tune custom altered to limit boost to 5 psi, and other tuners might do other things.
Hum, interesting, I thought I had seen 5 PSI somewhere and I had my readings matching that. Though my readings are not matching what I should have in power map. It should be around 21.5PSI per Cobb on stage 2, but I barely get over 20. Power figures and butt dyno feels much better than stock though and even the estimated HP and TQ are around and even higher than their max dyno gain figures, so that's good. I wonder if the reading is a little bit off somehow?
 


Messages
475
Likes
227
Location
Dublin, OH
#12
If your tune is set at 21.5 psi max and you are seeing over 20, that is surely within the accepted margin. Tune specs will often state that max boost achievable is +/- 1.5 psi from the value indicated in the tune specifications.
 


OP
W
Messages
8
Likes
2
Location
Lumberton
Thread Starter #13
Being stuck at 5PSI really sounds like being on the eco map as, if I remember right, it limits boost to 5PSI.

With cruise control off, press the cancel button. The RPM gauge will go to either 1 or 2 depending on the map it's on. 1 being power and 2 being eco (that's for the OTS Cobb map, different for other tunes). Switch between them with cruise up and cruise down, you'll see the needle go between 1 and 2 doing that. You have only a few seconds after pressing cancel to switch the maps, but you can do it as often as you want.

You can also check and switch them in the AP.

I have not got any surge on my 2014 sonce I've had it for a year, but I built it up to stage 2 from stock myself, so who knows what your previous owner did that might cause that.

Sent from my ONEPLUS A3000 using Tapatalk
This was the problem!!! Thank you so much for that. Blows my mind that they make it so easy to change, that it can be done on accident. Thank you guys so much. I guess now I will try and diagnose the surging issues.
 


OP
W
Messages
8
Likes
2
Location
Lumberton
Thread Starter #14
I have a Stratified tune with 2 eco slots (93 and E30) and the standard Stratified eco tunes are limited to 15 psi of boost, not 5 psi. The Cobb tune notes written by Will Trang state that economy boost is limited to 8 psi, which is a lot less than my Stratified tunes, but still not as low as the 5 PSI the OP is seeing. Of course, you can have the tune custom altered to limit boost to 5 psi, and other tuners might do other things.

Also, the "flutter" reported by the OP is an issue that GFB valve users have reported here, particularly when the piston builds up some crud. Cleaning the piston and lubricating it with a very coating of lightweight synthetic oil has been reported to fix it. That's why it might be a good idea to take a look and see if the OEM diverter valve has been changed.
Thanks for the tip! Will look into that this weekend for sure
 


Messages
453
Likes
345
Location
Orange
#15
I've accidentally left my car in Eco mode before. If I'm commuting, I want to keep my car on Stage 2 so I can cut and thrust in traffic. But, I put it in Eco mode for long boring highway trips. A few days ago I was trying to get around a Corolla and didn't have boost. Left it in Eco, oops..
 


KnockOff

1000 Post Club
Messages
1,348
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450
Location
Menifee
#17
I did it once. There was a 6 car wreck on my way to work and I got stuck in traffic for an extra hour. Once I cleared it I went to take off and the car felt like a reg fiesta lol. I was on the phone with my wife and thought that I switched maps but didn't know how at the time. Asked her to look it up and in 2 minutes the fiesta turned back into a fist. Now I change all the time. Eco for long stretches of the freeway and performance everywhere els.

Sent from my SM-G930P using Tapatalk
 


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