wont start from cold with a serious over fueling problem

can anyone help, my 1988 rangey classic has a intermittant but serious problem where it will start some days with no problem at all OR from cold will crank over and over with not a sign of firing up and a overwhelming smell of petrol, i believe its temperature related, ie a cold start sensor or something like that, i have replaced the distributor, coil pack, leads, plugs, but now think i was on the wrong track,, i can only start her when it plays up by pulling out the fuel pump fuse and cranking her over, foot to the floor, she fires up briefly and i quickly shove the fuse back in and she will run roughly for 20mins burning a massive amount of fuel until she clears and runs ok, not properly though,, other times i turn the key and she purrs??, i have been told maybe the e.c.u or a temp switch?? i have checked its not a stuck injector, i am now pulling my hair out,, she is a minter with only 36,000mls which is genuine!!, also a 4.5 conversion by oblig rover power when new so everything is based on the 3.5 efi,, it has to be something silly i have overlooked,,

if its 14 cu , ie flapper injection dry disconecting the cold start injector on the side of the inlet plenum. you wont need it in the uk anyway

I think the '88's also had a bimetal controled air valve mounted near the plenum, sometimes these fail and either don't allow enough choke air in or fail open and add to much air....

Called an Extra Air Valve....Does a similar job to the stepper motor/idel control valve fitted to the later Classics

thanks guys, i will give those items a look a.s.a.p, i thought it was something along those lines, i want to get the old girl up and roaring again, i have lost count of the amount of petrol ive used whilst trying to sort this problem,