"97 Swap Fuel Pump Question

I'm still trying to decide what I want to do with my fuel system on the '97 swap. I've seen where others have used adapter rings for the XJ pump on the comanche tank or have swapped in other tanks completely. Someone suggested to me that I just run an electric fuel pump and just cut power to the existing pump. Please excuse my ignorance (I've not messed with any of this fuel stuff before), but does this sound like a viable option?

I got a in line fuel pump on my '97 WJ. It's got over 6,000 miles on it with no trouble.I put a inline fuel filter in front of it and cut the power lead going to the old fuel pump and hooked it to the new one. Works great. Jim

I'm planning on buying a fuel tank for my short bed without the pan inside so I can run a cherokee fuel pump in it so the dash gauge will read correctly. Some have said that the gauge will move around some but if you don't let it get below 1/4 tank it shouldn't be to bad.

I'm planning on buying a fuel tank for my short bed without the pan inside so I can run a cherokee fuel pump in it so the dash gauge will read correctly. Some have said that the gauge will move around some but if you don't let it get below 1/4 tank it shouldn't be to bad.

Is this a slosh pan or something? How does the removal of the panel cause the gauge to move around?

If its a stock Comanche tank, how do you plan on adapting the Cherokee pump?

I'm really new at this and just trying to figure it all out. Thanks for the help.

This is one area I am not 100% which direction I want to go.

1) Follow Woodkrawlers way on JF

Besides using a custom fuel cell set up, the only idea I can come up with is to use a pump adapter ring like this:

http://copperheadfab.com/index.php?acti ... ductid=203

 

I "think" I will be able to block off the original hole on the MJ tank and cut a new hole in the top of the MJ tank to mount this adapter ring. Based off my measurements the XJ fuel pump/sender will sit about 1-2" off the bottom of the MJ tank when coming from the top. I need to cut the hole in the MJ tank to fit them and seal up the old fuel pump hole. The ring is the location where the hole will be cut. The ring will go inside the tank, then the pump sits down on the tank from the outside and a final ring mounts over the top of the pump, thus sandwiching the pump between the 2 rings and the tank for a seal.

 

Also we finished up the MJ/XJ tank conversion with fuel pump rings from Copperhead Fab. My fingers are crossed that this set up works. I really don't want to go the fuel cell route unless I just have to. With this set up I'm able to keep the stock tank in the stock location using the XJ high pressure pump. The only problem I forsee with it is the XJ pump sits about 2.5" off the bottom of the MJ tank so I "may" not get the max capacity out of the MJ tank. Also the XJ tank had 1 rollover valve and the MJ tank has 2. I don't think that will be a problem.

 

I am using the stock MJ tank, I've just adapted it to hold the XJ fuel pump. The Renix era fuel systems are a traditional send/return using 2 lines, one sending and one return. The later fuel systems, like on the '99 XJ 4.0L in my build, use a returnless system with only one sending line. Also the later fuel pumps are 49PSI versus a much lower PSI rating on the older style pumps.

2) TJ fuel tank/sender and gauge cluster

Shelbyluv does a good job showing what he had to do in order to get the TJ tank in place. We all know where to find that information.

3) Jeepman's adaptation of the XJ fuel pump/sender into a 1st gen 15gal Dakota tank.

I used the 92 Dakota tank and Yes the 98 XJ Sender fits right in and the cap screws right on, however I did use my factory 4.0L fuel line and vent lines and located the XJ Vacum canister under the truck oposite of the tank...

 

I drilled the AN (Dakota) tank to use the MJ rollover valves but they did not seat very well since the MJ tank is thin metal and the AN tank is thick plastic so If I fill too full it can leak a little but I have no real interest in fixing this as I am going to the larger tank and Will sort that out then... The AN 15 gallon tank is almost the exact dimentions of the MJ tank I had which is 18 gallons so I just welded a drop brackets to my MJ Box and used new MJ tank straps and it has been perfect ever since...

 

The tank needs to be dropped a little because of the Fuel pressure regulator that is ontop of the XJ sender as I did not want it up close to the box floor just in case I ever drop something into the box and the floor dents and damages the regulator...

WoodKrawler's method to me seems to be the easiest (and maybe the cheapest). The adapter ring is $60, which would probably be cheaper than sourcing another tank or a tank and gauge cluster. I didn't want to swap the cluster any way since the mileage is stored in the unit (that is correct isn't it?). I don't like the idea of losing capacity by using the adapter ring, but stepping down to a 15 gallon tank wouldn't help matters either. I wonder if it would be possible to fabricate a drop bracket for the adapter ring or modify the pump to space it down the extra 2.5".

Is there is any way of just bypassing the stock pump with an electric one?

I'm planning on buying a fuel tank for my short bed without the pan inside so I can run a cherokee fuel pump in it so the dash gauge will read correctly. Some have said that the gauge will move around some but if you don't let it get below 1/4 tank it shouldn't be to bad.

 

Is this a slosh pan or something? How does the removal of the panel cause the gauge to move around?

 

If its a stock Comanche tank, how do you plan on adapting the Cherokee pump?

 

I'm really new at this and just trying to figure it all out. Thanks for the help.

The pan that's inside the manche tanks is there to help keep the fuel level from sloshing around so the pump always has fuel and the gauge is accurate. However the stock manche sending unit's are no longer produced either by aftermarket or dealerships so it makes it extremely hard on those of us who need one. If swapping out for a fuel tank without a pan the cherokee sending unit and pump can be used as the only interference with it is being turned the other way and the pan being in the way.

I like being able to replace it without dropping the tank. So top load isn't a viable option for me.

I'm adapting the 97 xj sender to the mj unit and modifying an h.o. Xj pump and filter screen to it, with an mj float arm on it so that it will read accurately.

I like being able to replace it without dropping the tank. So top load isn't a viable option for me.

 

 

I'm adapting the 97 xj sender to the mj unit and modifying an h.o. Xj pump and filter screen to it, with an mj float arm on it so that it will read accurately.

I definitely want to see this when you do it. Please post more details when you can.

Read threw my build on Onyx. I tried the Copperhead ring. The slosh tray was in the way. I scrapped that plan and adapted a XJ sender to the MJ pump. It worked and was really easy.

Then I had the idea that a TJ cluster was better looking than a XJ one. :nuts: This involved a lot of work. I took some pretty decent pics of the X/MJ sender configuration.

EDIT: check page 11 on the Onyx build.

this is probly a dumb question but i don't k now the answer so ill ask. I'm doing a 4.0 swap in my mj and see you guys talking bout the fuel pump and fuel sender? is the sender just what tells the guage to show? sorry not my thread but I'm curiouse...

You're sort of right, the fuel pump mounts on the fuel sending unit (which for MJ's can no longer be purchased). The fuel sending unit is the piece that mounts to the tank that the lines run through the metal plate then curve down to the pump. The gauge sender is attached to the sending unit and has the float arm going through it to vary the resistance on it for the fuel level. I'm getting ready to buy a tank for my short bed without the pan inside as that's the only hinderance to being able to use an XJ sending unit in the MJ tank.

I'm getting ready to buy a tank for my short bed without the pan inside as that's the only hinderance to being able to use an XJ sending unit in the MJ tank.

I have not started tried to source a new tank yet but I am curious where you are finding a replacement tank without the slosh pan. I think this is the route I want to take along with the OEM 99 pump and sender with adapter rings.

I'm getting ready to buy a tank for my short bed without the pan inside as that's the only hinderance to being able to use an XJ sending unit in the MJ tank.

I have not started tried to source a new tank yet but I am curious where you are finding a replacement tank without the slosh pan. I think this is the route I want to take along with the OEM 99 pump and sender with adapter rings.

http://raybuck.com/i-66714-gas-tank-86- ... -o-fi.html

There's the one I'm planning on getting and they also have tanks with the pan in for someone wanting to buy a new one.

I have been thinking about this and was wondering if there was any way to just add a converter to the signal line of the gauge wire. I'm not great with EE stuff but I would think it would be easy to take the Comanche signal (I assume it is an ohm reading with a higher number meaning full tank and a lower number meaning empty tank or the other way around) and making a circuit that would take the ohm sweep and convert it to the readings that a newer Cherokee gauge cluster could read and understand?

like if the Comanche rheostat put out a reading of 100ohms for full and 0ohms for empty

and a Cherokee put out a reading of 50ohms for full and 0ohms for empty

couldn't you make a circuit that translated the information? so in this example if the Comanche rheostat read 75 (3/4 of 100)

the circuit could translate it to read 37.5 (3/4 of 50)

just thinking out loud.

here's another link for a tank without a slosh pan http://www.1aauto.com/1A/Gas-Tank/Jeep/ ... 79081/1987

so what i have gathered is with a tank without the slosh pan i can get my cherokee pump/sender to work?? how come i don't see anybody else putting a inline pump in?? that seems pretty simple to me so i must be missing sumthing.

here's another link for a tank without a slosh pan http://www.1aauto.com/1A/Gas-Tank/Jeep/ ... 79081/1987

 

so what i have gathered is with a tank without the slosh pan i can get my cherokee pump/sender to work?? how come i don't see anybody else putting a inline pump in?? that seems pretty simple to me so i must be missing sumthing.

you're going 4 cyl to 4.0 correct? what year 4.0 conversion?

if it's anything from 87-90, use an '87-90 pump and sending unit.

anything from '91-'95 or '96, use either a H.O. 4.0 mj sender, or combine the xj sender and pump with the mj sender and pump.

this topic is specific to '97 and newer swaps...so, if you're not doing that conversion, this topic is doing nothing but leading you astray.

the point of this topic is not about the fuel pump, but about getting the gauge to read accurately. the gas tank without a slosh-pan is necessary if you want to put the complete '97 sender in with the aftermarket locking ring.

I don't like that setup because the tank has to come down in order to swap the sender.

side note....an in-line pump will work great, if there's no pump mounted on the sender in the tank. if there is a pump in the tank,it will block flow, so your in-line pump won't develop the pressure it needs.

above that, your actual fuel level sensor needs to be specific to the generation of xj you're doing the swap from. otherwise your gauge will not read accurately.

ok thanks, i have a 89 mj 4 banger that I'm slowly putting my 4.0 in from my 96 xj.

I'm not against dropping the tank to swap the sender, so the tank without the slosh pan seems like a viable plan for me. However, I do have two questions:

1. How will not having the slosh pan negatively affect performance? Obviously there is a reason for having it in the first place, so what will eliminating it do?

2. Since the XJ tank is a different size, how will that affect the sender accuracy?

I'm not against dropping the tank to swap the sender, so the tank without the slosh pan seems like a viable plan for me. However, I do have two questions:

 

1. How will not having the slosh pan negatively affect performance? Obviously there is a reason for having it in the first place, so what will eliminating it do?

 

2. Since the XJ tank is a different size, how will that affect the sender accuracy?

empty will mean you have more left than you think you do, and your fuel will slosh in the tank a bit, but otherwise, no.

ok thanks, i have a 89 mj 4 banger that I'm slowly putting my 4.0 in from my 96 xj.

are you running the '96 xj wiring? if so, then use the '96 pump and sender mounted to the '89 sending unit.

in wiring do you mean engine harness? if so yes. ive got the cab forward harness swapped over to the xj, I'm using the xj dash guages ect. havent spliced/connected the rear harness together yet. too lazy and don't want to go work in my leaky garage. now to combine the xj/mj pump/sender do i still need the tank without the slosh pan??

in wiring do you mean engine harness? if so yes. ive got the cab forward harness swapped over to the xj, I'm using the xj dash guages ect. havent spliced/connected the rear harness together yet. too lazy and don't want to go work in my leaky garage. now to combine the xj/mj pump/sender do i still need the tank without the slosh pan??

I hope you're doing the dash wiring swap, too...won't work without that.

and no, you don't need to buy a tank. remove the comanche sender, remove the xj sender, swap the pumps and figure out a way to swap the xj's fuel level sensor onto the MJ sending unit.

I'm not against dropping the tank to swap the sender, so the tank without the slosh pan seems like a viable plan for me. However, I do have two questions:

 

1. How will not having the slosh pan negatively affect performance? Obviously there is a reason for having it in the first place, so what will eliminating it do?

 

2. Since the XJ tank is a different size, how will that affect the sender accuracy?

It will not effect a thing if you are running the 97+ fuel module. The slosh tray is built into the module.

I think the MJ and XJ tanks are just about the same height. If anything you may need to tweak the sender arm a little to get it to read correctly at empty. It might hang on full a little long than it should but it should be ok.

yes i took the entire mj wiring and dash out and have put in the xj dash and engine wiring. just trying to do research before i tear into it so itll be done right the first time. sorry for kinda jackin the thread but thanks alot for the info. :cheers: