Shibby Engineering Rail Cap

The Shibby Rail Cap is designed to block-off your factory pressure relief valve. Over time, factory pressure relief valves can leak and cause a drop in fuel rail pressure. This becomes even more evident in high performance applications. The Rail Cap will keep consistent pressure at the rail and not just return fuel to the tank. As an added bonus, the Rail Cap also works as a diagnostic tool when diagnosing no-start conditions. Installing the Rail Cap in place of a questionable factory relief valve can show if the OE component has failed.