I'll be bolting in the '96 4.0L into my '85 CJ-7 next Monday, and I'm wondering if anybody has modified an aftermarket 20 gal CJ tank to accept the '96 fuel pump/sending unit, regulator. If so, how's it done, any any tips would be greatly appreciated. If it can't be done, I might be forced to change out the fuel rail for a pre '95 with the rail mounted regulator. Thanks for the help.

I don't know much about the conversion, but I do know that the 96 4.0 fuel pump is a real POS. I know b/c I have replaced mine once and it is about ready to give out again also I have heard of many others replacing theirs.
Wish I could help with the swap info..
Good luck with the project.

Does the 20 gallon CJ tank have a round sending unit top like the 15 gallon one? If so you want to get a '87-90 4 cyl. YJ tank pump and sending unit. It is a drop in and the fuel gauge will be off a little but who cares. If the tank has a square opening you should use a '93-95 4 cyl or I6 YJ fuel pump and sender. These units allow you to use an external filter. I assume when you say you already have a '96 the unit is coming from a XJ because they did not make a Wrangler that year. I don't think I have ever seen anyone use a XJ pump and sender in a CJ. I think the tank shape is too differnt and it will not work. HTH.

gonna need a new tank and sending unit from 96 or newer or a new feul rail with the rail mounted regulator like you said. pick your poison. dont forget new fuel lines. should read up on fuel pressure too, make sure that the pre 95 regulator is high enough for the 96, yoy may need to get a new regulator as well that is rated high enough, these bastards can cost over $200

"If so you want to get a '87-90 4 cyl. YJ tank pump and sending unit. It is a drop in and the fuel gauge will be off a little but who cares. If the tank has a square opening you should use a '93-95 4 cyl or I6 YJ fuel pump and sender."

I had originally planned on doing just that, but the '96 and newer 4.0L's use an in tank regulator, fuel pump and sending unit, the pre '95 use a fuel rail mounted regulator.

I know that the '87-'91 4 cyl YJ tank will fit in the frame rails of my CJ, but does anybody know if the '96 and up fuel regulator, pump and sending unit will fit in the '87-'91 tank? I'd like to use a newer tank, but to my limited knowledge, nothing else fits. Anybody have any guesses?

I know the '97 and newer sending units are a very different shape because they go into a TJ tank. The TJ tank is very different for a YJ/CJ tank. If you are creative I am sure you can mount the guts of a TJ unit to a YJ/CJ stem. I have taken these things apart and they are usually just help together by a simple bracket off the return stem. You need to pull the CJ sender and then find a TJ unit and compare them. Sorry, but this is the extent of my knowledge.

I guess you could always swap fuel rails.

Thanks for the help DE. Did you have the same problem with your swap, or did you use an pre '95 motor?
For those new to this thread, the question is: Will a '96 and newer fuel pump and sending unit fit inside a '87-'91 YJ 15 gal tank? (OR) Will any '96 or newer fuel tank fit inside the frame rails of a '85 CJ-7? Once again, thanks for any help.