hi again , some updates. I've installed the fast glow plugs and hooked them up without firewall resistor (10V feed currency), It seems like the car began to start much better now ... but still sometimes I just can't start her up . this weekend was relatively cold, 39F at night, so I had no luck to start in the morning.. but this morning temperature was almost the same , ~ 40F , I primed the pump before actual cranking and engine started easy.. this leads me to believe that there is some air leak somewhere ... I've checked all the rubber hoses from filter to IP pump, replaced the fuel hose to primer pump and return, tighten all clamps, replaced prime pump... I've noticed that when I push prime pump it takes several pushes until pump starts to pump fuel ... so my question is what else could be wrong with mechanical prime pump, I've replaced that notorious part but maybe the whole prime pump body ,which bolts on to the IP pump needs to be replaced or maybe the valves inside it leak the air or fuel back to tank? or maybe the partial solution would be to buy a universal electrical pump and install it before prefilter ?
thanks for the replies .