How to Replace a Mitsubishi Mirage Fuel Filter | It Still Runs Insert the new fuel filter into the mounting bracket, with the fuel filter's arrow facing the engine feed line (do not mount it backwards). Tighten the bolts securing the fuel filter to the mounting bracket. Step 11 Attach the fuel lines. Mitsubishi Fuel Filter Problems and Troubleshooting While a faulty fuel filter can affect the starting of an engine, there are other possibilities to be examined before the filter is replaced. The first is for air leakage in the fuel pipes and the filter. At the rear of the engine on the left side on the firewall is the fuel filter. On top of the filter housing is a small pump.