We receive a number of phone calls from people trying to troubleshoot a no start problem, after replacing the injection pump. Or they have the engine started, but it will barely run, after replacing the injection pump. We provide an overflow valve (OFV), that the pump was calibrated with, and is installed in every rebuilt pump. Often times we receive cores that the overflow valve has been removed and kept. If you kept the overflow valve, then you would have an extra banjo bolt or OFV.
Pay close attention to the position of the overflow valve when you remove it. Note the difference between a fuel flow banjo bolt and the OFV.
Notice the large hole in the fuel inlet banjo, and the small orifice on the OFV (Overflow Valve). If the OFV valve is installed on the inlet side, it will restrict the fuel flow to the pump. If you installed a normal fuel flow banjo on the outlet, it will never build the internal pump pressure required for proper operation. The new style OFV on the left above, has the fuel return banjo installed as noted, with the acorn nut on the end.
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