OK, im doing my 4.0 swap and I just got a used TJ fuel pump in today. I believe my gas tank is from an 89 with a 4 cyl. I've read many places that a TJ fuel sending unit will work with these tanks, but my problem is that the pump I got is much bigger in diameter than the old one and looks to be in no way
similar enough to work. Am I mistaken and I need to get a TJ fuel tank? or is the pump I got wrong?
also, my tank is metal and everyone I've talked to says they're supposed to be plastic...could my tank be aftermarket?

Change the fuel rail on your TJ motor to a YJ fuel rail and run a frame rail mounted fuel pump.

I've never looked but I'd guess putting the TJ pump/sending unit in a YJ tank is gonna work easily.

CJ

what i did when i did the swap is i use hose clamp and tie down the TJ pump on my sending unit, and i use a gas tank from a YJ with a metal tank, those are the small tank. Or you could try to find a gas tank for a YJ that was on a Jeep with MPI, they use the same pump, YJ and TJ MPI.

RickyCJ7:D

seems like just strapping it down wouldn't make a good seal. did you do the same thing I am? IS there a modification that you do to the big plastic piece? I'm gonna try and find a tank that will accept it if its not too much... so a YJ tank with MPI will accept my fuel pump?

the senders are different from pre96 and 96 on
the tanks are different from 91-up.
personally, I'd rather see you sue a trailquest tank made for your Jeep that will hold the TJ sender. this will allow you to keep your current fuel rail and you'll only have to dick around with one fuel line, and let you have a cleaner set-up.

I'm on a budget and I think a used tank is the best way to go. So any 96-newer tank will work with the pump I have? I imagine one from a cherokee or grand cherokee will work also. Used stuff for those tend to be cheaper. ANyone know the physical dementions of those tanks? I want to mount it in the back between the wheel wells.

tanks made after 91 are wider than tanks made 90-down. they will not physically fit between the frame rails of 90-down Jeeps.
the only scrapyard soloution that I know of is to use a 87-90 4 cyl, 15 gal. EFI tank and sending unit, replace the TBI pump with an MPI pump, and replace the fuel rail with the earlier style rail that had the pressure regulator on the end of the rail with the return fitting.

That's not true. I put a 99 TJ tank on my 89 YJ that had the small metal tank before. It's just tight now and your tail pipe has to be put somewhere else. I only kept one of the fuel rail lines and put high presure fule hoses on them and flared them first. Works perfect.

every tank I've tried (3) is about 4" too wide for the CJ/early YJ frame rails. do you have a measurement on the width of the TJ tank? is it out of a 2.5L or a 4.0L. I'd like to know for my next swap.

I agree the TJ tank will not fit in the CJ 86 and before because there frames are too narow. But 87 YJ and newer have a different and wider frame and all the TJ tanks should fit! No I don't have a measurment but I can do it if you really want it? I would not be able to check today but I could find out Thursday night when I work on the Jeep? The TJ tank is out of a 99 4.0 L. I think all the TJ tanks are the same size!

how I got aroundthis was I bought an external fuel regulator from www.jegs.com mine was actually called acarborated bypass regulator. but it comes with two sets of sprins to make it work from 25-75 PSI (?????) I just mounted it on my fender.

it worked pretty well and it is adjustable. it is however $109

specs: 98 TJ 4.0 in a 94 4 cyl yj figured that would help you know where I am coming from

Not sure if you need it.... but I have a 19 gallon TJ tank for sale. $100 plus shipping and it's yours.

Paul