Stian, Original DeLorean fuel pumps have internal check valves, the later version uses an external check valve. There are several check valves throughout the fuel system, their function is to maintain fuel system pressure when the fuel pump stops running. This stored or rest pressure prevents vapor lock and allows the engine to quickly re-start. DMC Joe / De Lorean Services / <dmcjoe@xxxx> Web Site: <http://www.deloreanservices.com> ----- Original Message ----- From: Stian Birkeland <dmc_norway@xxxx> To: <dmcnews@xxxxxxxxxxx> Sent: Friday, February 04, 2000 9:01 AM Subject: [DML] Bosch Fuel Pump > Hello DML'ers! > > Investigating a bit around the DeLorean a fuel pump, I learned that this > Bosch part (along with other old Bosch fuel pumps) has been superceded by > one new Bosch fuel pump. It looks like it will fit very well, but I noticed > that this fuel pump has a so-called CHECK VALVE. > > Now, what does a check valve do? > And the original pump doesn't have a check valve, does it? > So will there be any problems because of this check valve? > > Best wishes > Stian Birkeland > NORWAY