E36 TT st2 over-boost

[Haifisch M3]

Many years of trouble free operation and all of a sudden over boosting
we have replaced waste gate, removed EBC and still over-boosting

any Ideas as to what else it could be?
BOW?

thanks

[E36M3LX]

Many years of trouble free operation and all of a sudden over boosting
we have replaced waste gate, removed EBC and still over-boosting

any Ideas as to what else it could be?
BOW?

thanks

how do you know you are over-boosting? boost gauge i assume? im sorry i am not familiar with your build.

hows the vacuum line going to the waste gate? maybe replace it just to rule that out. could fail internally and easily be missed during visual inspection

[Haifisch M3]

how do you know you are over-boosting? boost gauge i assume? im sorry i am not familiar with your build.

hows the vacuum line going to the waste gate? maybe replace it just to rule that out. could fail internally and easily be missed during visual inspection

Typical TT bottom mount build
new vacuum lines all around and still over-boost
over-boost determined by 2 independent boost gauges (greddy EBC being one of them)

[pbonsalb]

Could you have the wastegate hoses reversed assuming dual port WG? Could you have a boost leak occurring after the tap that feeds your gauge? Is the line to the WG from a source that would see boost (no check valve)?

[Haifisch M3]

Could you have the wastegate hoses reversed assuming dual port WG? Could you have a boost leak occurring after the tap that feeds your gauge? Is the line to the WG from a source that would see boost (no check valve)?

will check, thanks!

[mike radowski]

I know you said you have done some of this, but you need to verify the basics:

- Verify the system will run gate pressure by eliminating the bc altogether and running a boost source only to the lower wg port. Leave top port open. If this does not work there is a hole in the line or a mechanical issue with the wastegate(sticking valve in china gate, undersized, flex coupling liner swelling closed).

- Most newer external wastegates have multiple ports to allow for ease of install. Make sure if there are multiple port options that one or more "redundant" openings aren't open therefore causing it to act like the line has fallen off or has a hole in it.

If this works in the configuration above you can then troubleshoot the ebc/lines/etc.

[Haifisch M3]

I know you said you have done some of this, but you need to verify the basics:

- Verify the system will run gate pressure by eliminating the bc altogether and running a boost source only to the lower wg port. Leave top port open. If this does not work there is a hole in the line or a mechanical issue with the wastegate(sticking valve in china gate, undersized, flex coupling liner swelling closed).

- Most newer external wastegates have multiple ports to allow for ease of install. Make sure if there are multiple port options that one or more "redundant" openings aren't open therefore causing it to act like the line has fallen off or has a hole in it.

If this works in the configuration above you can then troubleshoot the ebc/lines/etc.

Thanks Mike
yup, was the waste gate stuck...not only the original old one but the new replacement as well...
Btw, the cutring h-gasket you installed 8-10 years ago held up perfectly even surviving multiple track days each year, and a 29psi over-boost event that fried a piston and bent 3 rods...