"Surging" issue when in boost

[techun]

My car seems to surge forward and backward during moderate acceleration, most noticably in 2nd or 3rd gear. It's bad enough to be noticed by a passenger. With the windows down I can hear my bypass valve going "pschew-pschew-pschew" while I hold the throttle steady, and a graph of my boost PSI has a ripple between 9-10 PSI while it's going on.

The car is stock, with 8k miles, and 93oct gas. I tightened all of my intake hose clamps aside from the driver's side intercooler one, which seems impossible to reach. If I give 100% throttle I can hit 18+ PSI, so I don't think this is due to a boost leak.

 

[Cesso]

The diverter valve and wastegate are electronically controlled, it could be an electrical issue with their connectors or something in the ECU. As your car is under warranty, I'd take it by your dealer and have a diagnosis done.

 

[me32]

I say take it in. you could contact the ford service on the site to help along too

 

[blurred]

how did you get a graph of your boost if the car is stock..?

 

[white-rhyno]

how did you get a graph of your boost if the car is stock..?

Accesspro without a tune installed? Just a guess. Or some other OB2 datalogger

 

[Joszer]

The same is happening with me, I thought it was a new tune of mine, guess not since it is happening to you. Let us know of any updates.

 

[daloonie]

I have a similar issue. Only noticed it after a dyno tune, but I haven't listened for any blow-off noise when it is happening. I might try on my way home from work today.
As of late though the effect has lessened slightly. I noticed it most just after the tune.
My best guess would be the ECU with the overboost function trying to regulate the boost mid throttle. But I could be wrong as there is many theories on how overboost functions.

 

[techun]

how did you get a graph of your boost if the car is stock..?

Accesspro without a tune installed? Just a guess. Or some other OB2 datalogger

Bluetooth OBD2 adapter and Torque App on an Android phone.

 

[techun]

I have a similar issue. Only noticed it after a dyno tune, but I haven't listened for any blow-off noise when it is happening. I might try on my way home from work today.
As of late though the effect has lessened slightly. I noticed it most just after the tune.
My best guess would be the ECU with the overboost function trying to regulate the boost mid throttle. But I could be wrong as there is many theories on how overboost functions.

Try being in 3rd at 2-3k and giving it pretty decent throttle and hold your foot steady. That's when I notice it most.

 

[daloonie]

I usually notice the surge most in 4th and 5th from 2k RPM and up.
Couldn't hear any blow off noises on the way home. Then again it was a little busy on the road. Will try again when it has quieted down. Still on stock air intake.

I will have to get some bluetooth OBD adapter and record some logs, if possible, of the problem. And see if the pressure drops. The surge definitely seems to have dropped the 2 months since the tune.

 

[techun]

Well the car is in the shop, but the dealership says they can't recreate the problem. There's still time before I need the car back, so I may be able to show them, but I'm not happy about it. Attached are some graphs of my boost psi during steady throttle input.
http://imgur.com/a/EjSUd

 

[FordService]

The same is happening with me, I thought it was a new tune of mine, guess not since it is happening to you. Let us know of any updates.

Have you been able to schedule an appointment with your Ford Dealer to get this diagnosed, Joszer? Shoot me a PM with your name, VIN, mileage, dealer, and best daytime phone number, and I'll see how I can help.

I have a similar issue. Only noticed it after a dyno tune, but I haven't listened for any blow-off noise when it is happening. I might try on my way home from work today.
As of late though the effect has lessened slightly. I noticed it most just after the tune.
My best guess would be the ECU with the overboost function trying to regulate the boost mid throttle. But I could be wrong as there is many theories on how overboost functions.

Hey daloonie,

I recommend contacting Ford Denmark about this, as they're going to be in the best position to assist you with this. Their number is 43 68 2000.

Nick

 

[Joszer]

Have you been able to schedule an appointment with your Ford Dealer to get this diagnosed, Joszer? Shoot me a PM with your name, VIN, mileage, dealer, and best daytime phone number, and I'll see how I can help.



Hey daloonie,

I recommend contacting Ford Denmark about this, as they're going to be in the best position to assist you with this. Their number is 43 68 2000.

Nick

Thanks for the follow up, I was able to get my tuner to tune the surging out of the car. I believe it was an issue with the updated boost tables and throttle mapping. All is good now =)

 

[FordService]

Thanks for the follow up, I was able to get my tuner to tune the surging out of the car. I believe it was an issue with the updated boost tables and throttle mapping. All is good now =)

Glad to read this has been resolved, Joszer - I'll be here should you ever need anything down the road!

Nick

 

[techun]

They replaced a boost pressure sensor, and it seems to have fixed the problem. I'll probably need to drive it for a week or so to be sure, since it was kind of an intermittent issue. So far it all seems good!

 

[techun]

Well I was able to reproduce the problem again. I guess I will live with it for a bit and see if it improves or gets worse. I may ride along in a friend's FiST and see if his does it too.

 

[therealandrew]

Any luck or update with this issue? My Fist has started doing this too. I have a laundry list of things and just added this and waiting to see my dealer but they are refusing to look at my engine because I have a COBB cold air intake.

 

[Joszer]

Well I was able to reproduce the problem again. I guess I will live with it for a bit and see if it improves or gets worse. I may ride along in a friend's FiST and see if his does it too.

Buy a COBB Accessport and have Adam from MAP perfoance tune your car. He tuned that surging out of mine

 

[techun]

Buy a COBB Accessport and have Adam from MAP perfoance tune your car. He tuned that surging out of mine

The main reason I got rid of my 2006 GTO for this car was the warranty.

I can definitely hear my bypass valve rapidly releasing boost over and over again. Pretty sure this is incorrect behavior...

"pschew-pschew-pschew-pschew"

 

[15performanceblue]

The main reason I got rid of my 2006 GTO for this car was the warranty.

I can definitely hear my bypass valve rapidly releasing boost over and over again. Pretty sure this is incorrect behavior...

"pschew-pschew-pschew-pschew"

If it is rapidly releasing like that, it is because the ECU is seeing an over boost code and is trying to release the pressure to save the turbo. So for some reason you are most likly getting a false over boost code. The dealer should be looking into the adjustment of the wastegate. There is an issue there for sure. My dart did the same thing, ended up getting the turbo replaced before I got rid of it.