Sti is overboosting... Need advise AGAIN!!!!

[cobbtunedsti]

Cool thanks

 

[HolyCrapItsFast]

Yeah, I agree with fugi... I see nothing wrong. Boost is not a constant anyway. It all really depends on load and RPM. Higher Load and Higher RPM will result in higher boost. If you overshoot your target (spike) and you see it fall that just means the ECU is doing it's job and reducing waste gate duty cycle to achieve the target. Plus the dyno is testing the car harder than you ever will on the street so the odds of you recreating this condition in that same gear on the street is not very likely or not to the same extent. Does this happen on the street?

I would only worry if you shot to like 24 psi and stayed there. A 1 or 2 psi spike would not phase me.

 

[IGOTASTi]

So I think I'm good???

Yep your good. A ok there shortie.

 

[cobbtunedsti]

Thanks again!!

 

[cobbtunedsti]

Still having OVERBOOSTING issues

I thought I sloved my issue when I found my uppipe plug had came loose.. I don't know how to slove this issue and I don't fell like driving down to Plano Tx.. Usually I have overboosting with an exhast leak!!

 

[05STiOwner]

do you have stock or aftermarket boost solenoid?

 

[cobbtunedsti]

Cobb's 3 port..

 

[STi FR3AK]

Did you build that vacuum/exhaust leak tester?

 

[cobbtunedsti]

Yes but i never can build any pressure!!! I hooked it to the inlet!!The air is coming out below the Throttle Body. I just hear air coming out but can't feel anything..

 

[HolyCrapItsFast]

I moved the thread into the engine section and merged the thread with your original. This will keep all of the history in one thread. :tup:

From what you just described it sounds like you have a major leak. That Must be addressed before we can go any further.

 

[cobbtunedsti]

What do you suggest?

 

[HolyCrapItsFast]

Perhaps perform the test again but this time also burn an incense. Bring it close to the area until it has the most effect on the trail of smoke. That will get you close to the area and at least you will know where the leak is.

Although I believe this is not the reason you are over boosting I do believe you must investigate and fix this first.

Can you do me a favor please? Make a log and post it. I just want to confirm the leak in the log.It should go rich under boost. Just one WOT in third and fourth. You should log...

A/F Correction 1
A/F Learned 1
A/F Sensor 1 Ratio
Boost
TD Dynamics
MAF Voltage
RPM
Throttle position
Waste Gate Dutycycle
Boost Target
Calculated Load

Thanks
George.

 

[cobbtunedsti]

Sure.. Once I get to a PC. I already have the logs.. Man... I'm so tired of having these problems.. I've never made it through an oil change without an issue. The past events that happened (vacuum leak, overboosting)could have ended my car.. I'm just going to try to do all my own work now.. I hope you know the feeling?

 

[Bluedemon_II]

Usually with an exhaust leak before the turbo, you get lag if it is big enough. I could say that the solenoid could be malfunctioning.

Still the smoke idea is good. also if you don't want to drive down to tx then do it your self man! It's an easy job if you have patience and the tools to do it.

 

[HolyCrapItsFast]

Sure.. Once I get to a PC. I already have the logs.. Man... I'm so tired of having these problems.. I've never made it through an oil change without an issue. The past events that happened (vacuum leak, overboosting)could have ended my car.. I'm just going to try to do all my own work now.. I hope you know the feeling?

If you can please take a fresh log with the parameters I highlighted above. :tup:

 

[HolyCrapItsFast]

Usually with an exhaust leak before the turbo, you get lag if it is big enough. I could say that the solenoid could be malfunctioning.

Still the smoke idea is good. also if you don't want to drive down to tx then do it your self man! It's an easy job if you have patience and the tools to do it.

Exactly.

Also I was thinking if there is a leak after the turbo outlet compressor side, boost will leak to atmosphere and there should be a drop in boost... not a spike or over boost condition.

 

[STi FR3AK]

Exactly.

Also I was thinking if there is a leak after the turbo outlet compressor side, boost will leak to atmosphere and there should be a drop in boost... not a spike or over boost condition.

^This. When I was at the drag strip (a long time ago) I was running low 14's and couldn't figure out why when I was normally low 13's. I checked my boost gauge and was only running 11psi instead of 20. I popped the hood with the car on and sure enough my pos "turboXS" bov was unscrewed enough to where it was leaking. I tightened it and wheeeeee low 13's again.

 

[cobbtunedsti]

Usually with an exhaust leak before the turbo, you get lag if it is big enough. I could say that the solenoid could be malfunctioning.

Still the smoke idea is good. also if you don't want to drive down to tx then do it your self man! It's an easy job if you have patience and the tools to do it.

I have noticed bad lag lately..

 

[cobbtunedsti]

Exactly.

Also I was thinking if there is a leak after the turbo outlet compressor side, boost will leak to atmosphere and there should be a drop in boost... not a spike or over boost condition.

So before the turbo (inlet?) I could have a leak? I know the 3 inch inlet was a Pain to get on the turbo.. It's tight but it could have slipped off..

 

[HolyCrapItsFast]

Not really... Here's what I was thinking. You have a leak after the turbo somewhere. Either way a log will confirm that by showing us rich fuel trims during WOT and either normal or lean trims during normal cruising. Or if you have a leak before the turbo this will also show in the log as lean trims all the time. Either way a log will reveal an issue.

As for the over boosting I believe this to be the tune and you simply need an adjustment. But you can not do that until you confirm the leak and fix it. As you suggest when you pressurize the intake, you can hear the leak and the system looses pressure. By that description you have a leak somewhere.

Take the log first and then pressurize the system again and use the smoke to find it.

I will not comment any further until you have done this. :Sticks tongue out:

So before the turbo (inlet?) I could have a leak? I know the 3 inch inlet was a Pain to get on the turbo.. It's tight but it could have slipped off..