Boost Acting Weird...Need Help!

[b4christ15]

Lately, my boost has been acting a little strange. I have a Joe P. MBC set to 15psi and for the past couple days, after my car has been running for about 20 minutes, it'll take a lot longer to reach full boost. Normally, I hit 15 psi by 3k in every gear...now sometimes it takes as long as 4500 in 3rd gear to hit full boost. This is pretty random too, sometimes I'll reach full boost like I should, sometimes it'll take longer. I'm thinking it could be a leak of some sort, or maybe something to do with the wastegate Anybody can chime in and give me some advice would be appreciated

 

[oldman]

The fact that the problem is intermittent makes it difficult to pin point what it is, the best way is process of elimination and go through the usual suspects.

1. Bypass the mbc and test run. If problem solved, it's the mbc. If not, go to 2.

2. Disable the actuator and test run. If you get all out boost (make sure you feather the throttle and not let it go over 20psi) without the lag, you have an actuator that opens prematurely. If not, go to 3.

3. Disconnect the actuator arm and make sure the flapper is fully close by comparing the position of the arm and the lever at closed position. Also check for any exhaust leak before the o2 housing. If everything all checked out and problem persists, go to 4.

4. Perform a boost leak test as described here . Fix all leaks until system is able to maintain 20 psi.

If after all this problem still persists, the only thing left is the turbo itself. Good luck.

 

[b4christ15]

The fact that the problem is intermittent makes it difficult to pin point what it is, the best way is process of elimination and go through the usual suspects.

1. Bypass the mbc and test run. If problem solved, it's the mbc. If not, go to 2.

2. Disable the actuator and test run. If you get all out boost (make sure you feather the throttle and not let it go over 20psi) without the lag, you have an actuator that opens prematurely. If not, go to 3.

3. Disconnect the actuator arm and make sure the flapper is fully close by comparing the position of the arm and the lever at closed position. Also check for any exhaust leak before the o2 housing. If everything all checked out and problem persists, go to 4.

4. Perform a boost leak test as described here . Fix all leaks until system is able to maintain 20 psi.

If after all this problem still persists, the only thing left is the turbo itself. Good luck.

WOW.....guess that answers my question. I'll give it a try and see what happens...hopefully, it's not something serious. Thanx

 

[b4christ15]

I just took the car out for a quick ride before I tried anything and now it's always acting up. From when I started it to when I just parked it, it never made full boost before 4k