Excelerate

Merging on to the freeway today I took a look at my boost gauge - to my absolute surprise, instead of reading the 15 psi I'm set at, it was blasting up towards 20!!!

Fearing for my engine, I let off and drove without boost the rest of the day, but now that I'm home, I'm having a devil of a time trying to figure out what's causing this.

Setup is a manual boost controller tee'd off the intake manifold, and a Lindsey dual port wastegate. My gauge is an aftermarket VDO teed from the KLR boost input, so I'm pretty sure it's reading accurately.

Tested all the vacuum lines with an air compressor and someone plugging the other end with their thumb, no leaks in any of the ones that affect the wastegate.

Paulyy

have you done any exhaust mods just before this happend?

DeWolf

wind the boost down and see what the gauge reads.

Excelerate

Nothing changed on the car before this started happening, and adjusting the mbc seems to have no effect. Wastegate perhaps?

fast951

MBC tends to fail, it's easy to test. Remove an dinspect, blow through the IN port, adjust the ****, the flow on the OUT side should change. If it's not the problem, you can check the rest of the system:

1)If running in dual port WG, close the hose between MBC and WG. (keep the hose on the pressure side of the WG to open it). You should be running low boost. If not, go to step (3)

2) If running in single port WG, remove EBC, reconnect hose from pressure side (IC pipe or Manifold) to hose going to WG. You should have low boost. If not, go to step (3)

3) Check the line(s) from pressure side to the WG. If line is fine, check your WG.