Audi A4 1.9TDI 1998 start problems

[ademzuberi]

Hello,
in advanced sorry for any misused terminology, im not very informed for english terminology of vehicle parts.
I have a problem with my Audi A4 1.9TDI 1998, it doesn't pump the diesel from the filter, when i manually pump the fuel (with a small manual pump used when u change the filters) on filter exit it starts and goes for about 10 KM and it doesn't pump anymore, all the fuel lines are empty (from filter to the fuel pump), i changed the fuel filter, and the same problem occurs again, i checked the lines from fuel tank to the filter for air leak and they are ok.

Any suggestions
Thanks

[kenney]

try replacing the control valve on top of the fuel filter,if that does not help,i think you have a problem with the pump.

[ademzuberi]

Hello, thanks for your reply,
i replaced the control valve on top of the fuel filter the car works it starts even on -15 degree Celsius, but until the engine is at normal working temp, if i reach over 4000 RPM on gas, when i release the gas the car starts destabilizing (the RPM goes 8 - 11 and then goes at normal RPM) and after a 2-3 sec it works perfect,
the mechanic told me that this could be a cause of the oil pump, when the engine is hot the oil gets thin and the pump can pump it normally, but when it is cold it has problem pumping the oil.

Ill let him change the oil pump and ill inform u tomorrow.

Thanks