Having too much boost is not always a good thing!  Too much boost can increase air flow and intake temperatures that can trigger dangerous detonation.  You would think more boost would be a good thing, but if you don't have enough fuel to compensate for the increase in air flow and an intercooler that can keep intake temperatures in check, it can lead to a dead motor.

We'll concentrate on the first type - sudden and uncontrolled boost pressure increase - first.  This is something that happens all-of-a-sudden and can usually be traced back to the operation of the wastegate.  Usually, it's a failure of a properly operating wastegate that allows the boost to increase uncontrollably.  First check the vacuum wastegate line from the turbo compressor housing to the wastegate actuator.  The hose can come loose due to a bad hose or loose clamp.  The fitting on the turbo compressor housing can come loose or even pop off the turbo compressor housing itself.  The wastegate itself can fail due to a bad or torn internal diaphram, or the actuator or flapper can seize.  If the wastegate fails in the "closed" position, you will run into a problem with runaway boost pressures!

"Boost creep" is a more subtle type of uncontrolled boost pressure increase.
Check out our boost creep page here:
FC3S Pro:  Problems, Symptoms - Turbo, Boost Creep

For more information on detonation, please check out our Detonation page here:
FC3S Pro:  FAQ - Detonation

Ensure any boost controllers are working properly!

Questions?  Comments?  Send mail to:  reted@fc3spro.com