Turbo Leak (3 psi drop after one day of maintenance)
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I may have a new way of describing my problem. I saw somehwere someone posted that they feel two surges of boost. It used to be that if I hit the accelerator to trigger the turbo I would get stage 1 (boost spooling softly)(low demand for boost) then when I would floor it I would get this awesome kick into stage 2 (boost spooling instantaneously)(high demand for boost). But now I accelerate slowly and get stage 1 but then when I floor it it seems like the engine hauls more but the boost climbs slowly as if in stage 1.
Sometimes I think in econ mode the car tends to skip stage 2 altogether because as always in econ mode I notice a slow spooling. So I guess for some to reference my situation it feels like when I am in sport mode I'm really in econ.
Even thought SOMEHOW my car has climbed up from 4 psi to 6 psi, I don't notice this two stage boost anymore.
Please someone tell me you know what I am talking about.
Sometimes I think in econ mode the car tends to skip stage 2 altogether because as always in econ mode I notice a slow spooling. So I guess for some to reference my situation it feels like when I am in sport mode I'm really in econ.
Even thought SOMEHOW my car has climbed up from 4 psi to 6 psi, I don't notice this two stage boost anymore.
Please someone tell me you know what I am talking about.
i guess it depends on where in the rpm range you are?
wait for tech.....
Ok, added a boost gauge and was surprised at the result. The IPD ECU was putting out 11psi and the Stock ECU was putting out 11psi....hmmm. Something odd here. I called IPD and they are going to take the ECU back and program mine then send it back to me.
One thing I want to try before fiddling with the sparks and injectors this weekend is my BCS. If I were to bypass the BCS by disconnecting the turbo and wastegate hoses and instead connect them to each other instead of the BCS, should I get stock boost?
you will get what ever the wastegate is set to. I dont know what it is set to, but I am going to assume ~5psi. try it. no harm to aanything if you try.
No then it will be a low boost. As soon as there is pressure the waste gate will kit in and lower the boost.
So now that I already have a boost gauge and seeing as my car seems to be more than shaky with reliability, I have decided to go the cheaper route and get a $47 MBC as opposed to a $225 ECU tun-up.
My question is, should I wait till I get my lack of turbo problem fixed before ordering? I understand I should get the car back to stock first but I didn't know if there are any tricks to where I can actually use the MBC to help solve my turbo problem.
I am going to pressurize my system Wednesday evening because I am really hoping it is a simple leak. It seems it must be a leak considering I only have noticed the problem after my bro disconnected the turbo to fix the oil lines.
My question is, should I wait till I get my lack of turbo problem fixed before ordering? I understand I should get the car back to stock first but I didn't know if there are any tricks to where I can actually use the MBC to help solve my turbo problem.
I am going to pressurize my system Wednesday evening because I am really hoping it is a simple leak. It seems it must be a leak considering I only have noticed the problem after my bro disconnected the turbo to fix the oil lines.
See if you guys can figure out this next puzzle...
So I am not testing for leaks until tomorrow because of my schedule. I was on lunch break yesterday and thought I would try something funny. I wanted to see if a leak could cause non-erratic lower boost that my current problem ensues.
So I remove a nipple from the turbo tree cretaing a "leak" (or an extra leak if there already is one) in my system (I could feel the vacuum suction at idle). I did this while the car was running and noticed it idled with a different tone which is what I expected. What I didn't expect was that I had NO CHANGE AT ALL. If there was any change, it may have been a little better.
Now I'm not saying it fixed the problem because I could still only max out at 5 psi and was surprised I could still hit 5 with a leak but I noticed that the throttle response was better and turbo seemed to spool a little faster.
Today I am going to disconnect two nipples and see if it gets better or worse. What do you guys think about that?
So I am not testing for leaks until tomorrow because of my schedule. I was on lunch break yesterday and thought I would try something funny. I wanted to see if a leak could cause non-erratic lower boost that my current problem ensues.
So I remove a nipple from the turbo tree cretaing a "leak" (or an extra leak if there already is one) in my system (I could feel the vacuum suction at idle). I did this while the car was running and noticed it idled with a different tone which is what I expected. What I didn't expect was that I had NO CHANGE AT ALL. If there was any change, it may have been a little better.
Now I'm not saying it fixed the problem because I could still only max out at 5 psi and was surprised I could still hit 5 with a leak but I noticed that the throttle response was better and turbo seemed to spool a little faster.
Today I am going to disconnect two nipples and see if it gets better or worse. What do you guys think about that?
Last edited by Saleen9090; Jul 21, 2009 at 09:32 AM.
okay, if you had the TCV disconnected and drove it with the turbo not connected to the wastegate and you still only made 5psi, it is most likely a bad pluck. The pluck on the inside of the turbo could be stuck open. preventing you from boosting and more.
Gilber just found out his was stuck opened when doing the exhaust:
See....
Wait for others to comment.
Gilber just found out his was stuck opened when doing the exhaust:
See....
Late this eveing I will disconnect the TCV and try that to make sure it ain't a wastegate issue.
Because it will be extremely overboosting, should I let off the pedal as soon as it breaches 10 or so?
Because it will be extremely overboosting, should I let off the pedal as soon as it breaches 10 or so?
I have a crucial question I just thought of...
Is the signal from the turbo housing to the TCV the exact same as a boost gauge would read?
If so, I was thinking about getting an MBC and testing it externally from the car, setting it to open at 7.5 psi. If I did this then put the 7.5-set MBC into the car and the car ran like stock again it would prove to be a TCV failure and not a leak.
Also, a question of curiousity probably for Tech. The TCV gets a boost signal from the turbo, analyzes it, and sends out pressure to open the wastegate. How does this all work?
Basically, how does the TCV control the wastgate while crusing on the highway. When cruising on the highway there will be no boost signal from the turbo so where does the pressure come from to open the wastegate to let the exhaust bypass the turbine?
Is the signal from the turbo housing to the TCV the exact same as a boost gauge would read?
If so, I was thinking about getting an MBC and testing it externally from the car, setting it to open at 7.5 psi. If I did this then put the 7.5-set MBC into the car and the car ran like stock again it would prove to be a TCV failure and not a leak.
Also, a question of curiousity probably for Tech. The TCV gets a boost signal from the turbo, analyzes it, and sends out pressure to open the wastegate. How does this all work?
Basically, how does the TCV control the wastgate while crusing on the highway. When cruising on the highway there will be no boost signal from the turbo so where does the pressure come from to open the wastegate to let the exhaust bypass the turbine?
The pressure side of the turbo sends pressure through the control valve to the waste gate. When the turbo needs to be bypassed the bypass valve opens and dumps the pressure back into the intercooler system/motor. The waste gate is open untill you build some pressure and then it closes.
Check out Gilbers posts in one about the exhaust I edited one of his pics showing why it was stuck open. See what that looks like then check and see if yours has the gap like the one in the pic. If so then there is your boost loss.
Actually here is the pic.
Check out Gilbers posts in one about the exhaust I edited one of his pics showing why it was stuck open. See what that looks like then check and see if yours has the gap like the one in the pic. If so then there is your boost loss.
Actually here is the pic.
They make a good point. The could be the problem, when that wastegate was stuck open, the turbo spooled really slow, never created much boost. once i got that fixed by replacing the housing, the difference was huge. I noticed that the turbo was spooling faster and I was actually getting boost. It would make sense, because it seems a little odd to all of a sudden have a boost leak after doing some maintenance, but it would also be weird for the wastegate to suddenly become stuck open.
P.S. tipsp and tech- I have those pics copyrighted, soooo... uhhhhhh...yeah, just saying..

P.S. tipsp and tech- I have those pics copyrighted, soooo... uhhhhhh...yeah, just saying..

Ya it happened right after maintenance however my brother never took the turbo housing apart. It could be coincidence.
Before testing for leaks, I plan to disconnect the vac lines running to the TCV and see if I can overboost.
If I can overboost (say over at least 10 psi) then the wastegate must be fine but if I get stuck at 5 psi again, the problem will be found.
Before testing for leaks, I plan to disconnect the vac lines running to the TCV and see if I can overboost.
If I can overboost (say over at least 10 psi) then the wastegate must be fine but if I get stuck at 5 psi again, the problem will be found.


