Mods in sig. I've been tuned at 25psi for a year and a half now no problem. Last week I was at Lime Rock and blew an upper intercooler hose off. No big deal. Reattached it and went back out but I wasn't able to boost past 12psi. I tried troubleshooting it today to no avail. I put Tbolt clamps all around on the intercooler piping, replaced the vacuum lines and even ditched my crappy TurboXS MBC for the Hallman. After all that, I'm still at the same 12psi no matter how much I turn up the MBC. I guess it could be a boost leak but I kind of doubt it since I'm boosting to exactly wastegate pressure. Wideband reads fine.

Most of these threads are about the system being set up incorrectly, but that's not the case with mine. It was working for a year and a half but something beyond the intercooler hose blowing off happened at the same time I think. Nevertheless, I see a boost leak test in my future. Any other thoughts or suggestions beyond this?

 

Don't all rush to help at once!

I've since replaced the wastegate as well. No change, still holds at 12psi like before. None of this is due to installation. It worked, popped and then didn't. Ideas?

 

first do a boost leak test check egr vac lines, vac line to boost gauge and exhaust leaks

 

Overspun the turbo and burned it up?

 

Your car might be in limp mode. Reset the ECU.

 

^the ecu will reset itself out of limp mode after a couple of miles of normal driving.

Op check your manifold for any cracks or any exhaust leaks before the turbo from the gaskets they might have blown. I had a problem similiar to yours and everyone kept saying I had something hooked up wrong but it boosted fine before. One tiny crack along a runner caused mine to boost to 14# at redline and everytime I shifted it had to build boost again as if I had just went wot. Over time it went down to only boosting 10psi.

 

Are you using the compressor J pipe as your boost reference source?

 

i think the fact that you hit wg boost at 12psi is coincidence. check your j pipe make sure its bolted on correctly still. licp could have moved it and blown the seal between it and the turbo. your best best is a boost leak test.

 

Update: boost leak test revealed zero leaks. Tested at 20psi, 25psi and then 50psi for the heck of it. Absolutely no hissing whatsoever. Boost leak ruled out.

Not 100% confident in the used wastegate I got off here, I bought a Forge unit to hopefully fix the problem. Needless to say, it didn't fix it. I used the adjustment video posted on here and no dice. Maybe I could try adding more preload but it should work fine the way it's adjusted (and both other wastegates I've used have the same result, so it's not that).

So now I'm at a loss. Replaced MBC. Replaced wastegate. Flapper looks good. No exhaust leak. No boost leak. Turbo is fine.

Any last ideas before I resort to bringing it to a shop?

 

i have the same problem ....after my intake pipe blow out

i will have to check my intake maniflod today

 

Boost leak with soapy water spray??

Also check the vacuum lines for cracking. Very slight, also check you boost reference source. That line might now be loose.

 

justboosted02: well, ive been helping doug with his problem and I am out of ideas,

We preloaded the forge wga all the way and the boost stayed the same.

we then pulled the vaccum line to the wastegate and it is still boosting 12-14psi. There are no signs of an exhaust leak.

Has anyone had an issue like this before? Could it possibly be a bad turbo. The wheels on the turbo look fine, there is no contact with either the comp or turbing housings. The car does not smoke, which indicates that the seals in the turbo are good.

 

Don't you kids have anything better to do on a saturday night than to look at turbos? JK

 

12 PSI is just about base WG pressure. Is this the max pressure that you see if the MBC is cranked all the way in clockwise to the highest boost setting?

Does it make any difference whether the MBC knob is cranked all the way in as opposed to being turned al the way out? Or, is it the same 12# regardless?

 

Where in CT are you??