MBC set at 15psi, running 22psi?

[jim90TSi]

Ok guys I have a 1990 awd, big 16g,ported 2g o2, 3 inch dp. I have a dual stage turbo xs mbc and both sides are all the way down(should be 15psi) I was driving my car tonight and it was boosting a hard 22psi. Ran faster than a scalded dog, but 22 is way way to much right now. Anyway, what would cause such a big boost spike like that? I would like to return to 15psi asap. Im getting around 43 counts of knock with 22psi untuned

 

[Heavy-D]

For a few weeks, my car's manual boost controller wouldn't work and I would hit 21 PSi with stock turbo. I thought my wastegate actuator stopped working cause its so old, my problem wound up being one of the little hoses came loose.
So two things it might be are the wastegate actuator or a loose hose coming of the MBC.

 

[jim90TSi]

All my hoses are on there tight.

 

[crankbender]

All my hoses are on there tight.

Remove the boost controller....

If you still are not boosting correctly you have either a creep problem or the actuator is broken/disconnected.

 

[fastalon82]

Ive heard nothing but bad thing about the turbo xs B/C so it may just be a bad unit. However for the time being, you really should at least back both knobs out and try to get your car to STOCK boost and start from there. Dont worry abour what the directions say, just get it to 10 psi and then start taking it out for some test runs and every now and then pull over and give it a quarter turn and see where your at. Also, see how much boost you can run before you start getting knock, then once you get knock turn it back a half psi and stop there.

 

[97EclipseGS-T]

well like the wise man said, you want to eliminate what you installed, so take it off. Run stock boost and if it occurs, you can have a boost leak, exhaust leak (my downpipe came loose and I did boost spike alot), you also might have it connected wrong.....or if worst comes to worst, you got all boost happy and wastegate is broken/disconnected.

 

[jim90TSi]

Remove the boost controller....

If you still are not boosting correctly you have either a creep problem or the actuator is broken/disconnected.

thanks man, the boost controller is bad........i took it off, found a bunch of crappy vacuum lines, replaced them and it sitll spiked past 20. I took it completly off and the car runs perfect at 11psi.

thanks again..........it was a turbo xs dual stage by the way for future reference on crappy mbc's