Hi all, got a 2013 fiat florino 1.3 multijet. Got to start it cold or hot and it just turns over for around 10-15 seconds as if the fuel has run back to the tank. No fault codes, replaced the fuel pressure sensor on the rail, just fitted a new pump with the new pressure reg, when on live data checking the rail pressure its on 0 until the engines cranks to start then it flies up and starts, knock engine off and it drops all pressure almost straight away. Checked the fuel pump in the tank and that's all working like it should. Any advise would be great,
Thanks

Hi

There is a few spots where it can bleed back to the tank..

Worth checking them

How long does it take to build that pressure from 0 to idle pressure while cranking?

Around 10 seconds,

Checked all the pipes from the tank to the filter and from the filter to the pump, all seem good even fitted a non return valve in the fuel line to prevent any return. Only thing I can think is its losing pressure through the injectors?

Checked all the pipes from the tank to the filter and from the filter to the pump, all seem good even fitted a non return valve in the fuel line to prevent any return. Only thing I can think is its losing pressure through the injectors?

Sorted, no3 and no4 injectors leaking the pressure into the bore. Fitted pair of injectors and fault sorted