[kelvin2010]

Two days ago, I took my car to track. Got into "half engine power" mode, but it was gone after I restarted the car. I was running 35% E85 on map5.
After the "half engine power" mode, I notice the car has been running slower than usual and only created 10psi boost. So, I did two datalogs and found out JB4 turned into map4 by itself.

Then I contacted Terry immediately. We have been making few changes on the setting. After that, the car has been creating more boost and no longer go to map4 by itself. But the problem is the car creating too much boost than it should be, it is creating 20psi.

After doing some changes, the car is still overboosting. So, Terry recommended me to go to a local tuning shop to address the overboosting problem, he thinks the problem is not about the tune, it might be the wastegates. My car runs and sounds normal.
Any of you have similar experience or have any idea before I go to the shop?

By the way, thanks Terry for his helps! He is awesome and replies e-mail just in a minute.

[Myaddiction]

I'm sure you want through the PID settings with Terry but I'm curious to know what they are at and what settings have you tried?

[kelvin2010]

Originally Posted by Myaddiction

I'm sure you want through the PID settings with Terry but I'm curious to know what they are at and what settings have you tried?

The PID was 20, now lower to 10.

[kelvin2010]

Originally Posted by Myaddiction

I'm sure you want through the PID settings with Terry but I'm curious to know what they are at and what settings have you tried?

fud=2, pid gain to 10, boost limit to 18 and also lagfix=0
What do you think?
Want to try as much as I can before I spent that money to address the problem at the shop..

[enrita]

sticky wastegate?

[Myaddiction]

I'd disconnect the vacuum line at the wastegate and hook up a mighty vac hand pump and see that it operates smoothly and that it's opening at the correct pressure. I'm not sure what the spring is set at for our cars. It'd be less then the factory 8 psi. probably 6psi or so. That'd be a start.

[TenshiWingusu]

Originally Posted by Myaddiction

I'd disconnect the vacuum line at the wastegate and hook up a mighty vac hand pump and see that it operates smoothly and that it's opening at the correct pressure. I'm not sure what the spring is set at for our cars. It'd be less then the factory 8 psi. probably 6psi or so. That'd be a start.

The N54 wastegates close under vacuum. Hook up the hand pump and pull it down, they should close fully at about 7" hg vacuum and should hold whatever level of vacuum you put on it. If not then it needs adjusting or replacement

[kelvin2010]

Originally Posted by TenshiWingusu

The N54 wastegates close under vacuum. Hook up the hand pump and pull it down, they should close fully at about 7" hg vacuum and should hold whatever level of vacuum you put on it. If not then it needs adjusting or replacement

Sounds like all you guys agree with the wastegates is the cause of this problem?
The wastegates don't rattle at all... Does it matter?

[kelvin2010]

Originally Posted by Myaddiction

I'd disconnect the vacuum line at the wastegate and hook up a mighty vac hand pump and see that it operates smoothly and that it's opening at the correct pressure. I'm not sure what the spring is set at for our cars. It'd be less then the factory 8 psi. probably 6psi or so. That'd be a start.

No code is showing up, I think if I take the car to the dealership, they will refuse to do anything...
Is it a difficult job to test it out?

[JamesM3M5]

Any competent shop that knows N54s and their proper operation can test all that stuff, but you can just buy a Mityvac hand vacuum pump WITH gauge (some don't have a gauge) system for about $50. Pull the WG vac hose off after the solenoid, pull vacuum, and watch the WGA rod. It should stop moving at 6 inches of mercury (inHg) vacuum. Factory spec is 200mbar, which is 5.9inHg. At that point of vacuum, the wastegate actuation rod should not move any more.

You will only be able to see the rear WGA/rod easily. The front is buried between the block and turbo. You may be able to see a tiny bit of the rod moving if you remove the metal rail that holds the solenoids to the side of the head. Checking the rear first will give you an idea whether they are really loose (not stopped at 6inHg vacuum). Also move the rod by hand. There will be some spring force in the WGA to overcome, but you should be able to do this on a cool engine with just your hand/fingers. The rod should actuate smoothly. Sometimes the shaft that goes inside the turbo housing gets badly worn and sticks/binds. That can lead to underboost that suddenly shifts to overboost when it binds open, then gets slammed and binds shut.

[cn555ic]

Originally Posted by enrita

sticky wastegate?

+1

[Jeff@TopGearSolutions]

Yea sounds like sticky wastegate. Common problem on tracked vehicles, more so in extended road courses.

[Myaddiction]

Originally Posted by kelvin2010

No code is showing up, I think if I take the car to the dealership, they will refuse to do anything...
Is it a difficult job to test it out?

Is it under warranty still? If so does it act up in map 0? You could take the JB4 out and tell them the power is inconsistant and have them check the boost then they will see it. If it doesn't act up in stock mode you might have a problem getting them to fix it.

It doesn't need to rattle to have a problem with the waste gate.

[kelvin2010]

Originally Posted by JamesM3M5

Any competent shop that knows N54s and their proper operation can test all that stuff, but you can just buy a Mityvac hand vacuum pump WITH gauge (some don't have a gauge) system for about $50. Pull the WG vac hose off after the solenoid, pull vacuum, and watch the WGA rod. It should stop moving at 6 inches of mercury (inHg) vacuum. Factory spec is 200mbar, which is 5.9inHg. At that point of vacuum, the wastegate actuation rod should not move any more.

You will only be able to see the rear WGA/rod easily. The front is buried between the block and turbo. You may be able to see a tiny bit of the rod moving if you remove the metal rail that holds the solenoids to the side of the head. Checking the rear first will give you an idea whether they are really loose (not stopped at 6inHg vacuum). Also move the rod by hand. There will be some spring force in the WGA to overcome, but you should be able to do this on a cool engine with just your hand/fingers. The rod should actuate smoothly. Sometimes the shaft that goes inside the turbo housing gets badly worn and sticks/binds. That can lead to underboost that suddenly shifts to overboost when it binds open, then gets slammed and binds shut.

Originally Posted by Myaddiction

Is it under warranty still? If so does it act up in map 0? You could take the JB4 out and tell them the power is inconsistant and have them check the boost then they will see it. If it doesn't act up in stock mode you might have a problem getting them to fix it.

It doesn't need to rattle to have a problem with the waste gate.

Originally Posted by Jeff@topgearsolutions

Yea sounds like sticky wastegate. Common problem on tracked vehicles, more so in extended road courses.

I just did another datalog on map4 which is stock mapping. Found out the boost looks normal on map4. Here is the log, please take a look..

[kelvin2010]

Bump

[Razodo]

Kelvin, any updates on this?
Im going through the same situation and can't figure out. I am mostly getting overboost fault code 30FE but did get underboost 30FF before. Curious to know how you resolved the issue. Did you test the wastegate solenoids?

[kelvin2010]

Originally Posted by Razodo

Kelvin, any updates on this?
Im going through the same situation and can't figure out. I am mostly getting overboost fault code 30FE but did get underboost 30FF before. Curious to know how you resolved the issue. Did you test the wastegate solenoids?

I didnt do anything to it. After other two tanks of gas, the car has been running fine since then.
The only problem that I am having is, when I do full throttle accelerating straight line, the car runs fine. But when I am driving in the curves, doing half throttle or so, the power is not constant at all. The car runs weird... It only happens on Map5, but fine on Map1 and 2