SX4 tank mods

[BaldEagle]

Hello all,
I've searched and found very little in the way of SX4/Kammy tank mods, so I'm hoping anyone that's done anything will mention it here. In short, my car gets fuel delivered, but that's all. She's slow to fill and won't fill entirely, spits gas, holds the pump hostage, and is only accurate to 1/4 tank. I know that mpst of the problems can be corrected with an added vent line, but have found no one who has added one yet. Any other mods would be great to know, while the tank is out anyway............like a replacement filler neck or different sending unit.
Thanks,
~E

[shaggimo]

Are you talking 6 or 4 cylinder? 6 cylinder models already have a return and vent line (not sure about the 4 cyl though, may not have the return). Anyway, there should be a valve in the vent line (fairly close to the sending unit, little canister looking thing), if it gets pluged it can cause similar problems that you describe. I'd check there first, remove the vac hose from the side facing the tank, see if it cures your issue. You can buy new senders still for these, but filler necks, not so much.

[carnuck]

If the charcoal cannister under the hood was modified/removed/plugged, then this is one of the problems that happens after.

[BaldEagle]

Oh yeah.......it's a 6 cylinder, and has had the charcoal canister removed. I hadn't considered it to be a source of the problems, because I don't think any of the lines were plugged. Is there anything that can be done with the lines to fix the issues, or does it just need the canister put back in?

[vangremlin]

I had to create my own filler neck as the original one had been sitting in the same tank of gas for 15 years and kind of melted.  I used two different sizes of filler hose, one fit in the hole in the tank and the other fit the gas filler neck behind the license plate.  The sizes worked out that the smaller one fit very nicely in the larger hose.  I clamped the top to the filler neck, and then also put a clamp where the larger one fit over the smaller one.  Has worked really well for me.

And as shaggimo said, you can get new sending units, which is what I had to do.

[carnuck]

I used the steel fill pipe from my parts wagon on SOTE which had the all rubber fill that was rotted off by the 20% winter grade alcoholized fuel here in WA.

[captspillane]

An XJ fuel tank is the same dimensions. I plan on cutting the filler hole out of a rusted through SX4 tank and bonding it over a hole I'll create in the XJ tank. The biggest reason to consider this is if you plan on going to MPI in the future. When an in-tank fuel pump runs out of gas it recovers as soon as more gas is put in. My external fuel pump became terribly vapor locked the one time it ran out of fuel, so the engine wouldn't start even after the tank was filled. I've also seen Chevy Fuel pumps adapted to the bottom of the AMC tank pickup where the filter sock would be, so it's still possible to have an intank fuel pump without replacing the original Eagle tank.

A second reason to use the XJ fuel tank is that it has a side fill hole. I want to use that for two reasons. In my SX4 I want to double the fuel capacity by adding a fuel cell inside and then connecting the two tanks through the side fill of the XJ tank below the floor. On my kammback I would eventually like to seperate the rear body panel seam and create a tailgate. I've seen it done on a Gremlin with the same rear panels as the Kammback. The rear looked perfectly stock from the outside but the glass flipped up and the metal pulled out like a drawer. The hardest part is actually relocating the fill neck to the side.

[BaldEagle]

These are new developments, though it's been slow to fill for some time now. Certainly nothing that keeps it from going too, as we've already put 3K+ in miles on it. The neck itself may be fine with some filing and smoothing, because it just grabs onto the pump sometimes...............but after hearing how they can disintegrate, I'll be prepared. I'll disconnect that check valve on the vent line also, and see if that helps it to fill any faster. That's good to know I can still get a new sending unit, and fix the gauge. An XJ tank may be in the future too, but I've no plans to go FI. Thanks for all the mods and tips..........I'm sure that I'll be well armed to tackle these filling issues now!
~E

[carnuck]

If you get an '84 to '86 XJ tank (make sure it doesn't have TBI if 4 cyl '86!) they came without the in tank pump and the resistance values for the gauge are the same too.

[captspillane]

If you get an '84 to '86 XJ tank (make sure it doesn't have TBI if 4 cyl '86!) they came without the in tank pump and the resistance values for the gauge are the same too.

Thats good to know. Does the Renix system have the same fuel pressure value as the Chrysler system?

I'm currently installing a pair of 1992 fuel tanks because I already have them in stock. I'll be using a 1992 XJ tach and speedo already mounted inside the stock Eagle cluster. I'd like to keep the stock Eagle fuel gauge but don't mind retrofitting the XJ one like I did the other stuff. Do you know the difference in operating voltage offhand?

[carnuck]

I forget what year they changed the pumps, but the pressure regulator on the fuel rail is what changed in '91 for more pressure for the HO system (08/90 HO production started as did 23 spline AW4s)
   I think dash voltage was the same but the resistance in the tank from full to empty changed @'87 (actually reversed)

[shaggimo]

I'm running a 92 fuel sender in the sx/4, somewhere a little over half tank means empty, lol, I have yet to find time to correct this minute issue, but the guage does sweep the correct way. You can use a renix sender for an HO and vice versa, but the gauge will run backwards. My 88 chero has a newer sender, and of course, on my gauge E means enough, F means.........you get the picture  .