zfinger Posted December 10, 2014 Share Posted December 10, 2014 I just stripped a 2000 XJ and I'm getting ready to swap it over as soon as I know I've got all the pieces. The fuel system is what I haven't figured out yet. I read in some of the 97+ swap threads people using TJ components or modifying MJ tanks to fit XJ pumps. Whats the issue with using the stock MJ tank and pump? Or why can't the stock XJ tank be put in place of the MJ tank? Link to comment Share on other sites More sharing options...
johnj92131 Posted December 10, 2014 Share Posted December 10, 2014 Totally wrong physical size and shape. Link to comment Share on other sites More sharing options...
dave92cherokee Posted December 10, 2014 Share Posted December 10, 2014 The XJ tank goes from side to side under the hatch, pre 97 tanks had a pump that mounts in like the mj pump but is an exact mirror physically and resistance for float arm is backwards and had a fuel return lines. Post 97 tanks had fuel pumps that mount in from the top but still go from side to side under the hatch but eliminated the fuel return line. I've seen some people in the past swap in dakota tanks when they did the 97+ swap and reported good success with the fuel sender and mounting, so I'd recommend searching dakota tank on here to get ideas from that. Link to comment Share on other sites More sharing options...
Jeepman Posted December 10, 2014 Share Posted December 10, 2014 You can use the XJ tank if your Willing to mount it at the back of the MJ (kinda as it would be in the XJ) but not in the OE MJ location... Link to comment Share on other sites More sharing options...
87Warrior Posted December 10, 2014 Share Posted December 10, 2014 You can use the XJ tank if your Willing to mount it at the back of the MJ (kinda as it would be in the XJ) but not in the OE MJ location...Or if you want, you can strap the XJ tank in the bed... Link to comment Share on other sites More sharing options...
zfinger Posted December 16, 2014 Author Share Posted December 16, 2014 You can use the XJ tank if your Willing to mount it at the back of the MJ (kinda as it would be in the XJ) but not in the OE MJ location...Or if you want, you can strap the XJ tank in the bed... I'm leaning towards just strapping the XJ tank down in the bed for now. Next spring/summer I plan on building a tube bed and going to a fuel cell. I'd rather not deal with finding/installing a Dakota tank, but that's a good option. I'm also looking at modifying the MJ tank to fit the XJ pump setup. I'll be spending my evening doing some reading on how that works. Link to comment Share on other sites More sharing options...
zfinger Posted December 17, 2014 Author Share Posted December 17, 2014 For the fuel tank, there are a few different routes you can take. The route I chose to use was to get a new tank without a slosh pan and an adapter ring for the XJs fuel pump and assembly to work. I cut a hole in the top of the tank, and using the ring, dropped the XJs fuel pump in. Bolted it up and plugged in the wire harness. This will require the tank to sit lower than where is was, necessitating longer J bolts and spacers. You can use the J bolts from the XJ tank, and use anything you feel will work as spacers to keep the pump regulator from contacting the underside of the bed. 3/4 inch should be all you need. There are also threads explaining how to use a TJ tank as well as a Dakota tank. You are more than welcome to use whatever means necessary to make yours work. To keep the check engine light off because of emissions, move the charcoal canister from under the XJ to under the MJ. I mounted mine under the bed and ran hoses from the two hard plastic lines that come from under the hood over to the canister. Also I ran a hose from the rollover valves on the fuel tank to the canister. It is my understanding that the canister on the earlier 2nd gen XJs is under the hood. If that is your case, mount it where it should be under the hood and run your tubing as needed. Slosh pan? I assume that's some baffling down in the tank? Where did you find a tank without a slosh pan? And the adapter ring for the fuel pump, where did you get that? As soon as I get the fuel tank figured out, the swap is on! There's a mountain of parts taking up space in my shop right now. Link to comment Share on other sites More sharing options...
shelbyluvv Posted December 17, 2014 Share Posted December 17, 2014 86 MJ V6 fuel tank has no slosh pan. The rings can be had from copperhead fab. Link to comment Share on other sites More sharing options...
zfinger Posted December 17, 2014 Author Share Posted December 17, 2014 86 MJ V6 fuel tank has no slosh pan. The rings can be had from copperhead fab. So is using my 90' tank not an option? Can the slosh pan be trimmed or reworked to make room for the XJ pump? My MJ is still on the road, so I haven't torn into it yet and have no idea what the tank looks like inside. Fuel tank ring to add an XJ pump to another tank http://www.genright.com/ProductInfo.aspx?productid=APR1000#.VJDZpOv77yA Link to comment Share on other sites More sharing options...
Timeless Posted December 17, 2014 Share Posted December 17, 2014 Interesting...I hadn't previously considered installing the OEM XJ tank under my comanche. Any one have pics of an XJ tank installed where the spare tire would go or similar location? Maybe your slosh pan can be trimmed, but how the heck are you going to get into the tank with any sort of cutting apparatus to trim it? Not to mention you will be introducing alot of debris into the tank that may never come out. Link to comment Share on other sites More sharing options...
zfinger Posted December 17, 2014 Author Share Posted December 17, 2014 I'd open up a good piece of the top of the tank. Kinda "can opener" it and peel back a flap, cut what I need to, then fold the flap back down and reweld it all. A good rinse should get out any debris. Long story short, my MJ was dead when I bought it due to mud in the fuel system. Tanks are easy to clean, and the inline filter will catch anything I miss. Right now that's my best option. Make the XJ pump fit the top of the MJ tank. Link to comment Share on other sites More sharing options...
Jeepman Posted December 17, 2014 Share Posted December 17, 2014 The 15G Dakota tank is near the same size of the MJ tank... 15G Dakota tank next to my 18G MJ tank Image Not Found Now the 15G Dakota Tank to the 23G Dakota Tank is a different story... Image Not Found Link to comment Share on other sites More sharing options...
zfinger Posted December 19, 2014 Author Share Posted December 19, 2014 Here is what I've come up with as a solution. I found a flange online that was aluminum and was meant for fuel XJ pumps into fuel cells. But it's $160 and I can make something close for cheap. Feel free to chime in if you see any flaws in my logic. I cut out the top of the plastic XJ tank where the fuel pump sat. Clamped that down on the mill and made the outer edge flat with the bottom of the groove. I made a simple steel ring, sectioned in 2 piece that will be inside the MJ tank. Bolts will point up and the XJ ring and pump will bolt down to the top of the MJ tank. The pump will drop in and the ring will screw on as it was designed to do in the XJ. I'll use JB Weld or some gas-safe epoxy between the plastic ring and the top of the MJ tank to make a leakproof seal. Link to comment Share on other sites More sharing options...
shelbyluvv Posted December 19, 2014 Share Posted December 19, 2014 If you shop around you can find the adapter ring for less than $100. Why risk a leak? Link to comment Share on other sites More sharing options...
zfinger Posted December 19, 2014 Author Share Posted December 19, 2014 Free > $100 Plus I'll be going to a fuel cell probably within the next year Link to comment Share on other sites More sharing options...
Jeepman Posted December 19, 2014 Share Posted December 19, 2014 I'd add a top ring just to better distribute a better seal otherwise looks good and inexpensive Link to comment Share on other sites More sharing options...
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