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Fuel tank question

tjmotter

tjmotter

NAXJA Forum User
NAXJA Member
Location
Texas
My '90 XJ fuel pump just died. The problem is that I filled the tank up yesterday. Anyone know how full is "full"? More specifically, how much am I going to have to siphon out to ensure I don't end up with gas all over the floor when I pull the pump?

thx
 
Oh man that's a problem. I'd try to siphon ten gallons at least. It's not just the spillage it's the weight. You'll have to loosen the tank straps to drop it down enough to replace the pump.

I've done this twice in our 92 Xj with 20 gallon tank. The first time a long time ago it had a problem with the locking ring with not sealing or bring bent. Had to get a factory replacement that took some time to order in. But it spilled all over and was a bear to deal with. I tried not to drop the tank at all but eventually had to to get it all lined up right.

Maybe somebody knows a better way but thats my experience.

I definitely try to siphon as much as possible out. The sender and fuel line are pretty high on the tank, I can't remember where ours stopped leaking at but it had to be 3-5 gallons from full. If it very full you could have over 22 gallons total. Depending if the tank is oem .
 
siphon 5-10 gallons out.

I used a transmission jack.

support the tank with the jack, loosen the tank straps some so the tank drops down a bit, but keep it supported. feed a ratchet strap over the tank and strap it to the trans jack for stability.

once its on the trans jack and strapped, then remove the tank straps and lower it. swap the pump and carry on.
 
Before assuming its a bad fuel pump have you bypassed or checked the fuel pump ballast resistor, swapped out the fuel pump relay, and checked the fuel pump ground located behind the plastic panel in the back were the spare tire mounts?
 
Green Mesa XJ said:
You'll have to loosen the tank straps to drop it down enough to replace the pump.

I've done this twice in our 92 Xj with 20 gallon tank. The first time a long time ago it had a problem with the locking ring with not sealing or bring bent. Had to get a factory replacement that took some time to order in. But it spilled all over and was a bear to deal with. I tried not to drop the tank at all but eventually had to to get it all lined up right.

Maybe somebody knows a better way but thats my experience.
Click to expand...

I don't know how much it may vary from one year to the next, but I did my '96 without dropping the tank or even loosening the straps. I did pay close attention to the twists and turns required to navigate the fuel level float and other obstacles on the way out, and I attempted to replicate the process in reverse. I didn't have any trouble and was quite happy with my decision to leave the tank in place.

As to the amount of fuel to drain, I would agree that ten gallons sounds reasonable.
 
i've done three xj fuel pumps: '96, '87, and '89(yesterday)...never had to drop the tank.
i think as long as you're no more than 3/4 of a tank, you "should" be ok in regards to fuel level.
 
Anak said:
I don't know how much it may vary from one year to the next, but I did my '96 without dropping the tank or even loosening the straps. I did pay close attention to the twists and turns required to navigate the fuel level float and other obstacles on the way out, and I attempted to replicate the process in reverse. I didn't have any trouble and was quite happy with my decision to leave the tank in place.

As to the amount of fuel to drain, I would agree that ten gallons sounds reasonable.
Click to expand...


It looked possible without dropping the tank. You can definitely pull the current pump and sender assembly as is without lowering the tank.

For whatever reason it was a colossal PITA to get the sender plate line up correctly with the tank. maybe the tank baffles are different.
I ended up putting a aftermarket assembly in all those years ago. Not long ago I put the oem assembly back with a new oem supplier pump. It still was a hassle getting the pump seated correctly. Not difficult I wouldnt go further than saying It was a pain to get lined up.

Edit: I my case it was easier to line up with the tank slightly lowered. But what I would do is siphon off enough to pull the pump sender assembly then see if you can put it back as is. If not you got plan b.

Of course double check the relays and fuses too
 
Last edited:
Green Mesa XJ said:
For whatever reason it was a colossal PITA to get the sender plate line up correctly with the tank.
Click to expand...

this has always been a pain for me. i spent a solid 30 min last night trying to get the stupid thing to seat correctly inside the tank. after fighting with it for a long time, it suddenly dropped into place and i just had to wiggle it around to get the rubber nipple on the return pipe to seat all the way into the hole in the baffle. i'd rather change a cps than a fuel pump any day...
 
thanasi85 said:
Before assuming its a bad fuel pump have you bypassed or checked the fuel pump ballast resistor, swapped out the fuel pump relay, and checked the fuel pump ground located behind the plastic panel in the back were the spare tire mounts?
Click to expand...

All diags have passed.
First, connected a fuel pressure gauge to the rail - no pressure
Second, I bypassed the resistor - no change.
Third, I crawled under the XJ with a meter in my hand and my wife behind the wheel. With the connector disconnected and the key on I have power to the connector (and good ground). With the connector re-attached and the key on, I have no noise nor vibration from the tank area.

It is the pump.

thx
 
Green Mesa XJ said:
Edit: I my case it was easier to line up with the tank slightly lowered. But what I would do is siphon off enough to pull the pump sender assembly then see if you can put it back as is. If not you got plan b.

Of course double check the relays and fuses too
Click to expand...

I like the way you think. I will try that first.

thx!
 
older XJs must be totally different. on a late model it is completely impossible to do it without dropping the tank or cutting a hole in the floor.
 
rockclimber said:
older XJs must be totally different. on a late model it is completely impossible to do it without dropping the tank or cutting a hole in the floor.
Click to expand...
Older XJ's have a front mounted pump and metal tanks..
 
Anyone have a good source for the proper tool for removing a rust seized lock ring on the fuel pump assy for an 87 XJ? I have already had three dry runs at it.
 
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