boost going up and down im scared!!

[rastok]

hi guys, long story short, lately the car is acting funny under wot acceleration in third and forth gear. I can see on my boost gauge, feel and ear the boost jumping under hard acceleration. When i hit the gas it goes up to 17-18 psi then drops to 14-15 then up again to 18ish it can do this 2-3 times then it slowly climbs back up to 18 if i keep my foot in it.. i thought i had a boost leak so i deleted the symposer, i bought and installed the mbrp hot side charge pipe and finally i installed the gfb dv and i still have the issue.. i also checked and tighten all the hose..

the car has an injen intake, a catless dp with full 2,5 exhaust, denso itv 20 irridium plug, fidanza lightweight flywheel, stock tune. I red about the target torque thing could it be that..

i dont know where to look now..

 

[TuxedoST]

Fun, mine does something very similar. Most days, it goes around 16-18 psi. On some days, even if the temp is the same, it gets around 16-18, then I'll stop the car, go into a store or something, come back to drive, and it'll go to 20 or 21 and feels WAY different.

Glad to see I'm not the only one having this problem....

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[rastok]

me it jumps from 14ist to 18 ish while im at wot... not the same issue there.. it bounce up and down

 

[Bretley]

Not sure if im reading right, but do you have a catless downpipe running on the stock tune?

 

[rastok]

Correct fmic is on the way then accessport and dyno tune is next

 

[rastok]

Why?

 

[Bretley]

Then it may be your torque target setting in the ecu. Also if your intercooler becomes heatsoaked, then the car will also run slower. Lastly, just having a catless dp without the proper tune may cause it to run different. Having that intercooler and accessport are definitely a good idea. You will see the gains from all those mods you have.

 

[rastok]

Yeah i cant wait to install it! I wanted it get everything inline before going pro tune.

 

[A7xogg]

factory overboost with ecu target torque is what im going with. tune will fix that

 

[zanethan]

Then it may be your torque target setting in the ecu.

^This. My guess is that your ECU is hitting the targeted performance numbers then compensating boost to not exceed them.

Ignoring the boost gauge, does it feel like its surging under WOT? If not then it is normal and something a tune will help to alleviate. However, if the car feels like it's surging at WOT then something might be off.

 

[eleven]

I had similar issues...it was the wastegate actuator...but I was properly tuned every time I added parts.

 

[rastok]

how can i check the wastegate actuator? im going under the car this afternoon to recheck stuff out..

 

[FearTheSnail]

Where are you at in the RPM range when it tapers off to 14-15psi? The stock turbo is quite small and will drop off up top.

 

[rastok]

climbing throught the rpm... while its going up from lets say 3k to 6... thats where boost is jumping up and down

 

[FearTheSnail]

That's completely normal. The tiny little Borg Warner KP39 starts dropping boost after it peaks a little bit after 3k. Looking at old logs from my wife's old ST before the DHM Quick Spool Kit, the car would peak around 3300 rpms and taper down to 14psi by redline. This was on a car with a protune. Are you running an off the shelf Cobb tune at the moment?

 

[FearTheSnail]

If you are on an off the shelf map, here are the tune notes. Depending on what "stage" you are running the boost levels will vary.

Ford Fiesta Map Notes

 

[rastok]

Stock map... when I slam it it quickly boost to 15-16 psi then drops back to 10 ish then goes back up to 15 and it keeps jumping between 10-15 like that...

 

[digglesworth]

I had similar issues...it was the wastegate actuator...but I was properly tuned every time I added parts.

So what ended up being the fix for that, new actuator?

 

[rastok]

lol there was no fix yer, we got a shit ton of snow and the car in sleeping since 2 days, im gonna get her tune then well see if this fix the issue..

 

[DANger_zone]

Thats a waste gate issue for sure (imo). i had a similar issue on my gti. Check that the wastegate actuater rod isnt stuck. Also pretty sure we have a vacum operated actuater and if the line is broken or loose or even if the actuator is cracked it can cause over boost.

If that happened the its posible the comp is seeing overboost before your gauge depending on were the sensors are and were your vacum line tap is.

Just an idea to ponder.

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