Here is a quote from Rick Schaefer's 4.0 swap page:
"If you own a CJ, here's the easiest way to get it to fit: All Jeeps from 76-90 used the same diameter opening on the fuel tank, whether it be poly or steel in construction. From 87 to 90, all Wrangler 4cyl Jeeps used a TBI injection system with an in tank pump that was physically identical to the MPI pump used in all 4cyl and 6 cyl. Jeeps built from 1991-1995. SO THEN, to get a factory in tank pump, you can use a pump for an MPI Jeep, along with a fuel sending unit for an 87-90 Jeep 4cyl motor, and get it to fit in any pre-MPI Jeep fuel tank. The wiring is as follows: Dark green w/ black stripe goes to the fuel pump relay. Dark blue goes to the sending unit. Black w/orange stripe goes to ground. Make sure you use steel or FUEL INJECTION RATED rubber hose when you plumb your fuel lines. Also, use fuel injection specific hose clamps for all of your steel-to-rubber connections. The fuel supply line goes to the injection line closed to the rear of the motor (closer to the firewall) and the return line goes to the injection line closer to the front of the motor. For all swaps you will need a fuel filter. I used a K&N reusable billet aluminum filter, but there are cheaper alternatives available for less than the ~$65 I paid to have some shiny widget under my hood."
It sounds great, but I haven't tried it yet. I am still trying to figure out everything for my 4.0 swap. Does anyone know if the TJ in-tank assembly is the same size as a YJ one? Or if the tank holes are the same on YJ and TJ tanks?
If your going to fuel injection you will probably want a "fuel injection tank". The differance lies in that the fuel injected ones are baffled, basically looks like a cake pan in the bottom of the tank to keep fuel to the pump so that it doesn't run dry. As far as adapting a fuel pump to the sending unit, no problem. I used I believe an f body (camaro) to a 89 sending unit. The pump is made by walbro who makes bbk, accel and others. I got the pump for 97 shipped. Its the hi po 255lph pump. The only reason I used such a big pump is because the motor is a tpi 350 and I want to be able to adjust my fuel. You don't need such a big one for a tbi motor.
MPI wrangler tanks wont fit in a cj, i tried. I've looked at both tj and yj tanks and I think, can't remember for sure but I think the tj sending unit bolt pattern is round while the yj's are square.
What i did was use a steel 89 wrangler tank and sending unit from a tbi 4 cylinder. This tank is baffeled and the sending unit is equiped with the pump. Then I bought the pump from Auto Performance Engineering Part number gss307m for 97.65 shipped and farbricated it to the sending unit. The pump will fit a variety of applications. There is a website for ape with a 1-800 number. The guy knows a lot about fuel pumps. Oh and the wrangler gas tank will drop right into the skidplate no problems. I reversed mine around so i didn't have to mess with the fuel filler location.
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