hey people when starting it takes ages to start, have replaced glow plugs and relay,changed fuel filter,air filter, took it vauxhall and fault reader said glow plug circuit fault but no engine maangement light comes on at all? the glow plug dash light only comes on in the morniing.also the the diesel doesnt seem to be coming through the filter on crank over? saying all this when its going it runs fine although a bit lack of power in 2nd. any help would be great because i'm a bit stumped been told its the gm enigine. cranks over about 6-20 times times and when it starts a cloud of smoke comes out the back which i believe is unburnt fuel?