What you are hearing is the reurn fuel ine. If you can hear it draining back, fuel pressure may be an issue as this is the high pressure line.
Unfortunately being in the USA, I don't have the test pressure for the diesel.
The petrol pressure, and probably the diesel can be taken of the fuel rail with a fuel pressure test gauge. If you can't find that test port, I have a diagram that shows a test port connectore between the fuel filter and fuel rail. The test gauge should have an adapter to fit the threads of the test port.
The spec for the petrol motor is 3.0-3.9 kg/cm 2. I don't think the pressure is the same for a diesel, but you can probably double check it on-line or get it from a parts store. I actually have some European specs and as this was the pressure spec for all, it most likely is the same for diesel, but I cannot say that with 100% verification.
Test it and if it is not up to spec, the may be an obstruction in the line causing pressure loss. I think doing the in-line fuel filter is definately the best move for now as if it is the original, it is surely impeding the fuel flow.
Get back to me with the results.
Thursday, September 22nd, 2011 AT 1:20 AM