charlie2sods

I am converting a 1990 4.3 to a carb, I am installing a new hei distributor with built in coil, using a motorcraft 2100 two barrel carb, i havent completed it yet but its getting close, i am installing a 4.5-6 lb. psi pump below the tank, I cut the red wire to the pump to use for the new pump. I notice the other day after disconnecting the sensors and the distributor that when i turn the key on the gas guage goes all the way to full and i know it has a little less than half a tank, i dont know what caused this, also the old distributor had a plug with 4 wires plugged into the distributor as well as the hot wire for the coil on the other plug. I am wondering if there is anything in those 4 wires that need attention that might be affecting anything, the oil pressure unit I was able to leave in place just had to turn it a bit. would anyone know why the gas gauge did that , or about the plug with the 4 wires that went to the old distributor, they werent the power wires feeding the distributor, would appreciate any thoughts on this as i am not an expert on this stuff.

Irish_alley

could that little red wire actually been pink with maybe a black stripe? if so thats your sending unit wire and the reason why your gauge is pegging out. i cant tell you what color your fuel pump wire is but im sure there should only be one or two more wires to choose from. the other wires on the dis. should of went to the ecm to tell the injectors to "fire"

charlie2sods

I just went out and checked that wire it is pink but no black stripe, you could be right I may have cut the wrong wire, the other one i think is white, it could be the power wire to the pump, i will check it out tomorrow and get back with you, thanks for replying

Irish_alley

i think the black stripe was dependent on the year

efilnikufecin

There should be 4 wires to the sending unit. I'm not versed on the colors, but the 2 thicker wires go to the pump, the 2 thinner wires go to the gauge. If only 3 then the pump and level sender use a common ground.

Either way if you are using an external pump you should remove the internal pump and replace it with a hose to reduce wear on the external pump. The internal pump also could lock up over time causing no fuel flow. overall better to be rid of it sooner rather than later.

Irish_alley

you might be able to find the wire harness http://www.73-87chevytrucks.com/tech...ing_Manual.pdf its for a 91 v series truck but it should be about the same

charlie2sods

the pink wire was the guage, i reconnected it and it works fine, and there is no voltage to either wire, there are only two wires, one of the plugs that was unpluged under the hood must have cut the power to the pump,

charlie2sods

i think im getting closer to figuring this stuff out, im not familiar with this 2100 ford carb, there are three vacuum stubs on it, one small one in front of the choke, which i assume goes to the vacuum advance on the distributor, and then there is one about a 1/4 in coming out from under the round plate on top of the carb that accesses where the air filter is, and one 3/8 in one on the bottom right hand back of the carb, can someone steer me right on what these are and where they go to, would appreciate it , thanks

oilcanhenry

Curious why you want to change out a TBI for a carburetor. I am GLAD carbs are almost gone, even in motorcycles..

charlie2sods

i will soon be 74, i want an old school truck that I understand and can work on, thats the shortest best answer i can give