Fuel Tank and pump

Mountaineer

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Hi, I just aquired a 1990 yj with a fuel injected 360 swap . I am replacing the fuel tank, a 15 gallon steel one with new 15 gallon one. The previous owner states that the original engine was a fuel injected 4.0 but what I am not sure what in tank pump I need. It has an external electric high pressure pump with a regulator, sucking gas from a bottom outlet on the tank (previous owner mod) and no in tank pump. I plan to keep the external pump but add an in tank pump as well. The problem is that the pump assemblies that I can find for that tank states that are for a 4 cylinder engine with the 15 gall tank. It seems that there is 15 gallon tank 1990 YJ with a fuel injected 4.0 and an in tank pump? Thanks for your help and excuse if confusing.
 

machoheadgames

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1990 was not a fuel injected 4.0 year. In 1990 you could only get a carbureted 4.2L or a throttle body injected 2.5L. The tanks of that year would be a metal 14.5 gallon tank with a circular opening, or a 20 gallon plastic tank with a rectangle opening. either engine could have either tank, though the typical was 4.2L 20 gal, 2.5L 14.5 gal.

In 1991 they deleted the metal tank, going all plastic, and they started limiting most of them to 15 gallons with a tube inserted into the vent tube that goes back to the filler neck. The tank was still the same size as the 20 gallon before and for the new fuel injected motors for 91, they started using the 87-90 sending unit with a fuel pump inserted into it. Somewhere in there, probably between 91 and 92, they changed the fuel sender ohm readings. the fuel gauges changed from 91 to 92, so that's why I imagine the ohms changed then.

So either that Jeep is not a 1990, or the owner doesn't know what engine it actually had.

If you are replacing with a plastic tank, I would just get a 91-95 fuel pump and sending unit combo, install it into the new plastic tank, and delete the external pump they added. The stock in tank pump is already high pressure and supports about 100 PSI. It would be pretty tough to out-engine the stock pump.
 
OP
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Thanks a lot for the reply. I already have a new 15 gallon tank, with the round opening, what about a pump and sending unit for this tank? Thank you.
 

machoheadgames

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Thanks a lot for the reply. I already have a new 15 gallon tank, with the round opening, what about a pump and sending unit for this tank? Thank you.
Don't see them very often. You can try this one: https://www.quadratec.com/products/55107_97.htm

I don't know the specs of it other than it was made for a 2.5L 15 (14.5) gal metal tank.

Looks like all the 87-90 TBI 2.5's had that 14.5 gal tank. Maybe that pump is good enough, but like I said not sure of the specs so you'd just have to try and see what psi it outs out.
 
OP
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Hi, have the new pump with a pig tail with 3 wires, gray, purple and black but not sure which one is what. The body pig tail fits perfectly with the pump but with different wire colors, orange with black stripe, brown with black stripe and black with yellow stripe. When I plug the pump with the body, the black goes with the orange with black stripe, the purple with the brown with black stripe and the gray with the black with yellow stripe. I understand that probably the pigtails shouldn't match because it did not have an inside the tank pump before, but curiously, when connected, the fuel gauge works but the pump doesn't. If at least I can decipher the pump wires, I can connect everything correctly. By the way, the original sender (with no pump) only had 2 wires where the black with yellow stripe body pigtail wire remained unused. Thanks a lot for the help.