To answer your question, I'm pretty sure your fuel gauge will read correctly with a 20 gallon fuel pump/sending unit assembly. My tank started life as a 20 gallon tank and I removed the sending unit and installed a 20 gallon fuel pump/sending unit. The gas gauge works as well as it ever did.

When I look at the '91-'93 parts catalog, the 1991 gauge is a different part number than the 1992-1993 gauge, but there's no reference to 15 gal or 20 gallon gauge.

When you get your new fuel pump, make sure to replace the 2" internal hose with a hose that's rated for constant immersion in ethanol gasoline. (see pics). Use fuel injected rated clamps. (see pic #2).

Good Luck, L.M.

 

Mine read way overfull for the first few gallons, but runs pretty much inline relative to remaining marks with the gauge till empty.

 

#metoo

 

@Luckymac Thanks for the advice on the fuel hose. I ordered a Delphi brand from Rock Auto. I'm hoping getting a major brand like Delphi the included hose is the proper hose, but in today's world where mfr would rather sell it for a few cent cheaper then include the proper hose, I will definitely check.

I ordered new fuel assembly gasket, fill hose and vent hose since the current one are likely original.

Any suggestions on what else I should consider replacing when dropping the tank?

 

@Luckymac
Any suggestions on what else I should consider replacing when dropping the tank?

It's easier to get the tank back up if the tailpipe is unbolted from the frame. However, it's fairly difficult to start the tailpipe bracket bolts with the tank in place. I modified my tailpipe btacket. See pic #1.
I bought a cheap angle drill adapter at Harbor freight so that I didn't have to drop my spring to drill the hole in the bottom part of the frame rail. (see pic #2. The bracket ended up close to the tank, but neither the tank nor the bracket move, so they never touch. See pic #3. A shot of black paint and it looks stock. (see pic #4).

You'll also note in pic #4, that my rear shackle bolts are pointing inward. On the drivers side it's very difficult to remove the shackle because the factory installs the shackle bolts pointing outward before they install the tank (see pic #5. While the tank is down, it's easy to switch direction of all 4 shackle bolts in preparation of ever having to install new springs or replace the shackle bushings (see pic #6

Use Anti-Seize on all the threads fasteners.

Good Luck, L.M.

 

I'd replace the roll-over vents and grommets and also make sure your shackle bolts are pointing outboard. When dropping the tank, you may need to use a ratchet strap to pull the muffler a bit outboard to make the tank a bit easier.
As to the hose thingie...it's not only whether its rated for fuel immersion (blue thread core), but it has to exceed your pumps max output psi, which can be up to 90 psi.

 

I got the replacement fuel pump and assembly today. What exactly am I looking for regarding the 2" hose?


It's a Delphi so I assume it's not low quality junk.

Looks like dropping the tank should be easy. I was able to remove the exhaust hanger which should give me enough space to work the tank out and loosened the 6 nuts holding the tank. Just need a siphon to get the 5 gallons in the tank out.

 

Take a look through this thread, if you look at the sidewall view in the last pic, you can see the difference in fuel line construction.
It looks like the stuff on that pump is the failure prone type. I'd swap it out before installing your new pump.

Yet Another In Tank Fuel Pump Fail.

Hopping onto the freeway the other day the engine sputters and dies. A quick check of the pressure gauge on the supply line tells me I got low pressure, but I can hear the pump running so of course the first thing that hits me is the damn fuel line burst in the tank like on so many others...

www.wranglerforum.com

 

I'd change the hose just to feel safe. Look at the hose differences in the link that GIAL posted.
Here's a pic of what I put on mine. Not cheap, but I think it was money well spent.
Note the FI rated hose clamps. You'll destroy the compression clamps when you remove them, so buy some FI rated clamps. The conventional screw clamps seem to not hold up well.
Also, see the pic with the hose rating.

Good Luck, L.M.

 

Installed the fuel pump last night. Gauge seems to read correctly with the 20 gallon fuel assembly. I siphoned 4 gallon and added 6 gallons at the gas station and the gauge reads exactly half full.

I have the Mountains double end box wrenches (same as the Icon), that was the trick to get the exhaust hanger bolts out with the tank installed. With the hanger removed the exhaust swings out of the way just enough to slide the tank past.

Thanks everyone for the advice and hits. I didn't swap the spring shackle bolts since the rubber bushings looked pretty dry rotted and didn't feel like opening a possible can of worms.

 

The Fuel pump I Bought wont fit into the Tank. Do I have A 15 OR 20 gallon tank....How / where can I get the SHORTER ONE ....91 Wrangler

 

Welcome to the forum!

Won't fit meaning not the same top (there is a round lock ring style and a rectangular bolt on style.
Or is it too tall to fit the tank? Most are adjustable To a degree. Some of the poly tanks when dropped will sink up to an inch making it a pain to get the new sender in.

 

Welcome to the Forum @msieraws

look at the bottom of your tank and the tank side of your skid plate.
Is the middle of the skid plate pushed up?
Is the center of your poly tank pushed up?
Is your sending unit contacting your slosh basket?
Is the slosh basket sides warped? There's an easy fix to a warped slosh basket that doesn't include removing it.

let us know what you find. It's unlikely the fuel pump/sending unit is too long.

Did you replace the little hose between the fuel pump itself and the outlet pipe? If you didn't, I strongly suggest that you do replace it with a section of FI hose that's rated for constant immersion in gasoline.

To discover if you have a 15 or 20 gallon tank, pull the vent tube from the tank (the smaller of the two hoses has a smaller hose in it. The inner hose should only be about 2-3 inches long. If it's any longer than that, you have a 15 gallon tank. To make it a 20 gallon tank, cut off the excess and put the 2-3" piece back where you pulled if from before you cut it. All poly tanks have a 20 gallon capacity. For some unknown reason, the factory installed a longer vent hose so that the tank could only accept 15 gallons.
I expect that your new fuel pump/sending unit is a 20 gallon unit. I don't think anyone makes a 15 gallon unit because most folks will do the 20 gallon mod while the tank is down.
For a more detailed explanation, Google "Jeep 20 gallon mod".

Feel free to ask any questions. You'll find most members here are eager to help.

Good Luck, L.M.