Hi changed out left most injector seal in 08 1.6 desiel  Tdci focus. First one I done worked a treat. Second one I done I forgot to tighten the fuel line into the injector before I tried to start the car. It took towing it for about 500 meters then it started all looked good. Stopped and started ok immediately but if you let her sit for a while she turns over longer than she did before and on restart goes ok. Now the car has not done a drive since  it was changed . But I am concerned that I a leave it till the morning it will not start. How long does it take to purge the fuel system after air gets in. Should I let here idle for awhile and see?.

4 hours ago, Maddog55 said:

How long does it take to purge the fuel system after air gets in.

The high pressure side of the fuel system should purge almost as soon as the car starts. There are return pipes from pump and each injector, that carry quite a lot of surplus fuel away at idle, and will vent any air. It is just possible there could be tiny air pockets left in the common rail, that would need a little more cranking to pressurise the system. A bit of driving should clear this.

The real problems are with the low pressure side, from tank to pump. This is under suction when running, and the pump will not work on air (at least not at cranking speed), so air in this part can prevent starting entirely.

Ran her today all ok. Starting back to normal