gvalve issues

[89boostedminivan]

ok im running a gvalve for boost control, recently here im having a problem with controling the boost setting, anything up to 15psi it will maintain that setting, over 15.. say 18psi, it will spike to 18 but then drop and maintain at 15, so basically anything i set it for above 15 it just hits it real quick then drops off to 15psi. i pulled the gvalve and made sure it was clean and all looked good, im gonna get a used MBC today from a local guy ( hallman pro) but does this sound like a boost control issue or something else??

[anokabball24]

It's probably because you're running a 2 bar MAP calibration, limited to 14.7 psi, anything beyond that and you'll hit fuel cut.

In case that isn't the issue, perhaps it has something to do with your wastegate actuator or a boost leak somewhere.

[89boostedminivan]

im running a gvalve for a map bleed. it was boosting at 18psi but now it seems to only spike at 18 and drop off to 15ish, im just thinking its the gvalve cause it is kinda old. do the springs ever wear out in these things? is it possible to that the turbo xs rfl BOV is leaking under high psi?? cause i was running 3 shims in it and then removed them cause i was having a problem with the BOV but found out i didnt have a big enough vac line to it, but im still running 0 shims since that problem

[89boostedminivan]

yep it was a shim issue in the BOV, put 3 shims back in and i can hold boost now :amen: