PECV
It controls the vacuum signal to the carburator power valve[PV].
During NA operation the manifold vacuum is conected to the carb. PV ,through the PECV ,which adjusts dependant on engine load. The vacuum will pull the main jet needles into the jets when the vac. is high, lean for light load. When the vac reduces, on heavy load ,the needle springs will lift the needles resulting in a richer mixture.
When the manifold goes into boost conditions the PECV will cut off the vac/boost to the PV. This prevents damage to the PV and also gives max. rich under boost.
If the PECV is not fuctioning correctly ,damage to the power valve may result.
