2002 td4 wont rev

have had the maf out this afternoon and cleaned it, still no joy. discovered one thing though, if i switch the engine on and rev it hard it goes all the way round to 5000rpm,then let it go back down to tick over and rev it again it stops at 3200rpm and wont go any higher. have tried this several times with the same result. anyone got any ideas?

Maybe you have pressure building up inside the engine, only a guess, rev it up with the dipstick is out if you are brave!!

try dissconecting the maf un try agin wont hurt it. . .

failing all of above. . .then its gonna be fuel pressure related. . .

is this engine breather thingy underneath the injectors or around that area? also can it be cleaned with wd40/brake cleaner or other such substantces, or do i need to replace it?

ming said:

failing all of above. . .then its gonna be fuel pressure related. . .

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If possible, connect a voltemeter to the fuel pressure sensor on the fuel filter housing. (Pierce the wires with pins so you can check the reading with the plug still connected.)

It should read about 4v at idle - i.e. 2.5bar. If you rev the engine the reading should barely change.

Ideally, run the wires though into the cabin and monitor the voltage when driving - ie under load. If the reading drops significantly, there is a fuel supply problem, most commonly due to a the in-tank pump.

Ron