Reinstall any of the remaining parts and hoses that were taken out during the installation, and double-check your work to make sure nothing was missed. The final step is to purge the fuel lines of any trapped air. If the engine won't start or runs poorly, loosen the banjo fitting above the fuel filter and use the push-button primer to free any air trapped in the main fuel line. If the engine still runs poorly or not at all, loosen the steel fuel lines one at a time and crank the engine until it appears that only fuel is escaping the fittings, then quickly tighten them. Use extreme caution during this procedure to prevent the high pressure fuel from puncturing your skin or spraying over a hot engine.