2004-2010 GM 6.6L Duramax Release Valve Shim Kit
California Air Resources Board Executive Order No. D-701-32
The Release Valve Shim Kit increases the pressure needed to “pop-off” the pressure relief valve (PRV). This means that the available fuel rail pressure remains high, as requested by the engine computer during full-throttle driving. Reduces the fuel flow through the fuel return system due to an age-weakened spring.
It eliminates potential low fuel rail pressure DTC codes P1093 or P0087 (low fuel rail pressure during power enrichment) that are caused by insufficient pressure relief valve spring pressure opening, returning fuel to the fuel tank.
Installation Guide: Release Valve Shim Kit