1989 Renault engine suddenly doesn't like starting

[Carpentersuperstar]

Hi, I don't know if anyone can help but our campervan, a Renault Trafic of 1989 vintage was always a joy to start firing up first time after the heater plugs went out..
I've checked the heater plugs, all working, changed the fuel filter but still she doesn't want to fire up as before.
The engine fires but doesn't run until I pump fuel , by hand up to the pump body.
I'm gong to anneal the copper washers on the pipe between the filter and the injection pump today as it seems to me that the fuel is flowing back to the filter which must indicate that air is entering from the injection pump end.

Does anyone have any ideas?

[Coilspring]

Flowing back TO the filter, or FROM the filter?

Has it happened since changing the fuel filter?

Is it parked on a slope? If so, park it in the opposite direction, see if any difference?

But it does sound like an air leak, just need to find where and why? Most obvious cause would be disturnance of the fuel system.

[Carpentersuperstar]

:-)Thanks for that. I annealed the copper washers of the banjo bolts between the fuel filter and the injection pump then bled fuel to the pump input banjo and went around all the unions just to check before trying to start her up this afternoon. I must have put something right as it started 2nd time. I reckon the first try was pumping fuel through the pump. so I'll leave it 'til tomorrow after work and try again to see how she starts.
Thanks for the reply though . I was sure it must be air getting in to allow the fuel to flow back to the filter, but I've been known to miss the obvious now that my brian is getting old so it's good to have someone to talk to about these things. Wish I'd signed up to piston heads back when all my lights went to dsco mode every time it rained.. My auto electrics people couldn't work it out and said I probably should try a plumber! :-)