What would happen if you read the fuel flow after the bleedback unit drains fuel off to regulate pressure? I.E. Tank --> Pump --> Regulator --> Flow Measurement --> Injectors ^ | +-------------------+ (I've not torn a car fuel injection system apart, just Carbs (Holly's & Quadrajets mostly ) - perhaps the pressure regulator is after all the injectors, but seems to me that if it's inline, adding a small flow measurement body inline AFTER the return line, would give the desired flow rate! Mark Willis, mwillis@nwlink.com Bruce Turrentine wrote: > > The problem with measuring fuel flow in a fuel system such as fuel injection > is the fuel pressure regulator bleeds fuel back to the tank to control the > pressure. Therefore, you would have to measure the fuel returning as well as > the total flow and compute the difference.