Will an XJ fuel pump fit?

I have an 87 MJ and the fuel pump is leaking from the metal elbows that come out of it. I have a fuel pump from an 89 XJ that runs when I plug it into my trucks harness and looks the same as the MJs except the leads coming out of it are straight rather than at a 90 degree bend. Are these otherwise the same pump? Airtex has the same part number listed for the two of them but I want to be sure before I go sticking it in there.

I've got a new Airtex #7091 assembly sitting in a box right now. The only difference I can see, even though they list it both for the XJ and MJ, is that the sock strainer at the bottom is rotated 90 degrees clockwise from where it should be. I'll be swapping it in in about a month or so, and was planning on modifying it somehow when I do....there is a small slot in the lower pump mount that lines up with a plastic tang on the strainer head. I was thinking of either cutting a new slot or using the pump mount from my current MJ assembly.

I can toss some pics of it up if you want to see them, lemme know.

Jeff

Well the pump I have is a stock one out of a Jeep Cherokee so it might be slightly different than the Airtex. As long as it seats in there right I should be fine. If I remember right I think the strainer can actually be rotated. I think the Comanche ones are weaker because of the bend in the hardline that goes into the tank, so hopefully this one will last longer.

just got home from work and looked at it again

the sock strainer is rotated 180 degrees, not 90, and is not adjustable.

Also, I'm wondering if the overall in-tank length is the same and if the return line will fit into the "cup" in the inner tank (it looks like it's the same by eyeballing it). The plate that fits into the side of the tank looks to be a bit more angled, too, but that can be adjusted by a careful bend of the hardline.

Can it work? probably

Can it work without some modification? looks unlikely

I've had my stock fuel pump assembly in and out 3 times now...thankfully neither of the hardlines have cracked where they are prone to. But, I disconnect the soft lines where the connect to the hard fuel lines on the body, not from where they exit the tank, just to be safe.

Jeff

We went over this a little bit ago. Dr. Thunder put in a remart sender. He said he got a clanging noise from something hitting the in-pan tank. The XJ/MJ units are not the same. The MJ one is no longer available. I've read on here that your two options are to either "fix" your leaking one by I think welding or soddering the the leak or to disassemble the remart one and reassemble it to mimic the MJ one. I don't think Dr. Thunder ever posted his solution to the problem. Maybe he'll chime in.

So to answer the original post. The XJ sender will not work in the MJ tank without modification like Jeff said.

Edit: I meant Airtex not remart.

Well I don't have the money to buying a new one since I just got this one and $40 it cost me. So I am going to pull it out and see if I can't make the Xj one work. Sounds like I would have to modify it even if I did buy a new one, so if I break this one it isn't as big of a deal. I'll report back for the record.

OK.....I'll pass on how I've repaired 3 sending units in the past couple years.

Correct!!! the XJ sending unit will not work on the MJ. Correct!!! the MJ sending units have not been made since like '94.

Your doing this at your own risk.

Remove the sending unit. Remove the fuel pump, and the sock. Flush it out with water, let it air dry couple hours.

I get 1/4" brake line, 8" long, I cut it in half, I bend each cut end 90* and remove the old steel lines at the end of the sending unit disk. I ream out the two existing lines and make the new steel line fit into the exiting lines. Then I mig weld the new lines on to the plate/old lines. Die grind the welds down. I use RTV sealant (gas ready) to seal the entire unit. Water test it. and done.

Oh.....yes, it's easier to bend the tubing before you cut it in half.

Using the brake line give you a 'flair' end for the soft line to slip over and stay on, with hose clamps of course. Using the 1/4" line fits into the pressures line with no problem, and the return line is slightly smaller.

You could solder or braze the lines in, but I prefer the welding. Steel to steel, welding is better. The RTV or any GAS sealer is just to make sure there are no pin holes.

After your water test for leaks, blow out any water in the lines and let air dry couple hours. Install in the tank and done.

I'm in the rust belt, and found out years ago the sending units don't exist, and had to come up with a repair for the old sending units. Every one I've done was the same, the 'tubes' rust out at the base / bend.

The next one I do, I'll do a write up and put it in the "project" section.

Thanks Wildman! I am still going to see if I can modify the XJ pump since I already have it and I am kinda pissed that I spent $40 on it before I realized it wasn't the same. This will be as much of an experiment as anything. So if (when?) I fail at that I will use your advice to repair my MJ one.

Ive been on the hunt for a sending unit as well.....i came across this today, would this work in an 88 4.0L SWB?.....looks like this may be our solution?

http://www2.partstrain.com/store/?N=921 ... ,year:1988),AND(universal:1))&Vi=10857+1557+4294966973&y=1988&mk=Jeep&md=Comanche

It lists the exact same part number as the 88 Cherokee, so probably not.

It will fit the Cherokee, and for some reason, parts manufacturers seem to think the Cherokee and Comanche parts interchange.

The sending unit I believe is turned 180 degrees from how it needs to be.

Yeah.....i have my Dealership (i work there, my family owns it) searching to get 1 somehow.......this really has been a slowly growing problem among us MJ owners over the past couple months :roll:

It won't work, but you know that. This is what sits inside of the tank that allows it to not work. I ended up soldering in a new line, still is working.

These guys might be an option for those who have run out of any other options.

http://www.tristarrradiator.com/

Looking up new gas tanks, I did find a number that specified NOT having a pan inside of them. With these tanks an XJ unit *might* fit.

Looking up new gas tanks, I did find a number that specified NOT having a pan inside of them. With these tanks an XJ unit *might* fit.

Yes, I believe it will work. However I believe the purpose of the in-pan tank is so a certain amount of gas stays level and that way your gas gauge doesn't fly all over the place. Now if that doesn't bother you, rock on baby, do it, and let us know how it goes.

Looking up new gas tanks, I did find a number that specified NOT having a pan inside of them. With these tanks an XJ unit *might* fit.

Quoted from the '89 FSM -

Fuel Reservoir

The fuel tanks of all Jeep vehicles are equipped with a fuel reservoir (Fig. 34) that provides fuel to the fuel pump inlet (fuel injected vehicles) or the inlet tube of the sender (carbureted vehicles) during all driving conditions, especially when the fuel tank has a low level of fuel. The reservoir is a small tray with raised sides that the fuel pump inlet or fuel sender sets in. The fuel return tube empties into small cup in the reservoir that is ported to the rest of the tank. When fuel from the return tube enters the cup a low pressure area is created causing additional fuel from the main tank to flow into the reservoir. The combination of return fuel and fuel from the main tank keeps the reservoir full even when the fuel level in the main tank is below the level in the reservoir.

I posted that, cause I thought the reservoir pan was for fuel injected, so I looked it up first. It saids all Jeep vehicles.

What your looking at is got to be an after market, which is nothing wrong with that.

I don't think a fuel tank from a XJ (Cherokee) would work, I have both at the shop, and tomorrow I can take pictures of them side by side. I'm thinking that the XJ tank is "flatter" and wider than a MJ tank. And you only have a few inches from the MJ fuel tank to the drive shaft. Of course, you could toss it in the bed and use it that way :brows:

These guys might be an option for those who have run out of any other options.

http://www.tristarrradiator.com/

Yea, that's an option......I think my method cost about $4 in parts and an hour of time. Seams like the same results.

I didn't mean using an XJ tank. I meant using an XJ pump/sending unit in an after market MJ tank without the tray.

But since I'm getting a used tank off you, it doesn't affect me :D

I didn't mean using an XJ tank. I meant using an XJ pump/sending unit in an after market MJ tank without the tray.

 

But since I'm getting a used tank off you, it doesn't affect me :D

Oh :eek: .....I read that wrong :oops:

I know, and it's been said that the XJ sending unit is "turned" 180* from the MJ sending unit. Like I wrote above, "re-building" the supply tubes worked for me, DrThunder had wrote that he replaced the tubes also. I think with our 20 year old trucks, we're at the point that some of the parts need to be made to keep them running :roll:

And Yes, I'll see you at the end of the month :D