Following on from O2 sensor and poor starting when hot issues, I managed to borrow a good pressure gauge and checked fuel rail pressure: result - zero until cranking! It also drops to zero immediately when switching engine off. There is no problem when driving and under load. The in tank fuel pump and filter were changed in October last year! Any ideas?

Len Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr

Last edited by Lenb on 17th May 2016 4:05pm. Edited 1 time in total

That fuel has to be going somewhere.
This happend (on another vehicle) to me and it was the seal under the injector.
It also happend to my son's TD5 and it was a loose fitting in the pipework somewhere.

As above, fuel pressure is dropping off due to it escaping. Either internally (e.g. failed non-return valve in fuel filter/pressure regulator or stuck open injector) or externally which hopefully would be a bit more obvious!
Also as Wealy says seems to be a bit more common on diesels due the higher pressures involved, I diagnosed a friends Disco TD5 recently with a failed injector seal (poor starting and higher fuel consumption).

Given you have hot starting problems but is fine if left I would be thinking injector issue. Fuel is dumped in the cylinder on switch off from a stuck open injector leading to an excess of fuel on hot start, if left it evaporates away and is fine on cold re-start. Does it smoke initially on start up when you have the hot-start issue?
What fuel pressure were you getting with it running? It should be 3.5bar.

If no other leaks are obvious I would be checking the injectors.

No smoking at all when it starts after hot start issue. The fuel pressure when running was about 3 bar (40 psi).

As an extra: my tank used to 'hiss' when removing the fuel cap but no longer - in fact the cap feels quite loose! Current: 2004 Vogue 4.4 V8 - 2004 Discovery 2
Previous: 2000 P38 DHSE - 1995 P38 DT Man - 1990 3.9 SE Classic, 1980 3.5 Classic 2dr