Rear Mount Gas Tank Write Up, Wagoneer

['89_Wagon]

Just completed a rear gas tank swap in my 89 Grand Wagoneer. This post is meant to document the process I went through.

Why did I do this? At half a tank, my Jeep would start to sputter, hesitate, or die while taking turns and accelerating out of a stop. It did this when carbed and fuel injected. I threw a new pickup tube and fuel pump at it and nothing changed. Later, I was running two fuel pumps and it was very noisy. Rust is also a concern in my area so the saddle tank setup would eventually become a problem.

Why this setup? This setup does not require any notching of the frame and the fuel level gauge seems to work well enough. The fuel pump design solves any fuel starvation issues when turning or steering. The nylon lines won’t rust or corrode and parts themselves are cheap. There’s also plenty of ground clearance and it moves the fuel tank to the spare tire area.

Why not this setup? The gas tank is smaller than stock…. 19 vs 20. For me, it felt like I doubled the size since I had to fill up at half a tank before. Pressing fittings onto nylon can be a pain without the proper tools. I gave it shot with simple tools and decided it wasn’t worth the frustration so I dropped a lot of money on the tool (I used KD tools kit). I’m happy I did since it saved me a ton of time. Obviously… no spare tire.

Does it work? Short answer, yes. I have no problems with fuel starvation, cold starts, and as mentioned before the fuel gauge is good enough. It’s also quiet. It can be heard priming when the ignition is turned on, but it’s muted. I can’t here it all when the engine is running.

['89_Wagon]

Parts List

-97 S10 two-door Blazer gas tank
-96 S10 Blazer fuel pump. This fuel lever sender reads accurate enough.
-Fuel lines. I used 5/16 and 3/8 nylon fuel lines and quick disconnect fittings. I paid a lot for the installation tool but the peace of mind was worth it as well as the ease of installation. I didn't want to fight with other methods of pressing nylon fittings to the hose.
-Fuel filter. I used one with 3/8 quick disconnect ends. The one I purchased was for a Buick Roadmaster.
-Quick connect fuel fittings. Keeping with the theme I purchased straight and elbow quick disconnect fittings. Fuel supply uses 3/8 and return uses 5/16.
-At minimum, four 3/8 fittings are needed. 1 @Fuel pump, 2 @ fuel
filter and 1 @ TBI.
-At a minimum, three 5/16 fittings are needed. 1 @ TBI, 1 for fuel
return at pump and 1 for the fuel tank vent port.
-Fuel line mounting clamps.
-GM 6AN fittings to replace stock pods. Found these on Ebay from a vendor called dstrumpet. Saves much needed space at the TBI.
-6AN to QD fitting. These mount to the GM TB adapter fittings above.
-Tank straps
-Hockey pucks. Cheap spacers.
-Rubber sheet, 1/8 thick an 3 inches wide. 10 feet was $16 on Amazon
-Double sided tape.
-Copper reducer 2” to 1”. Bough off Amazon.
-1 inch fill hose. 1 foot length
-2 inch fill hose. 1 foot length
-Over flow hose 5/8, 1 foot length
-Over flow hose 3/4, 1 foot length
-5/8 to 3/4 fuel line adapter for overflow hose

TBI fittings are optional. Barbed fitting can be pressed into the nylon hose and rubber lines can be ran from there.

Edit 5.14.21: Corrected nylon fuel line size to 3/8.

['89_Wagon]

More Pics to follow

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[SJTD]

Looking forward to more pics with hope it doesn't stick down as far a most of these installations.

['89_Wagon]

Here are some more pics.

[IMG]Gas tank by [url=https://www.flickr.com/photos/93784013@N04/][/IMG]
[IMG]Gas tank by [url=https://www.flickr.com/photos/93784013@N04/][/IMG]

Rear mount, looking up. The rear strap is bolted to the upper lip of the rear cross frame.

[IMG]Gas tank by [url=https://www.flickr.com/photos/93784013@N04/][/IMG]

[scottb]

When you say 5/8, do you mean 3/8? 5/8 seems large for fuel line. Thanks!

['89_Wagon]

Yep, good catch. Should be 3/8. I'll fix that.

['89_Wagon]

Been running this setup for a while now. No issues so far. Although, I haven't found a home for the tank vent tube yet....

[Warlordsix]

Looks good. I'm planning to use a polyethylene 20-gallon Wrangler YJ tank. Should be a straightforward swap, but I'm still running a carb, so I'll need to remove the electric pump from the tank and figure out a replacement, straight pickup tube.

Ernie

[devildog80]

You can use the in tank pump, just check your carb pressure needs, as you might need to only put a pressure regulator in line and a bypass back to the tank.

[Warlordsix]

Roger. Thanks. That would require an adjustable fuel pressure regulator that could take it down from somewhere near 50psi to something under 8psi (I'm running a Holley 1450).

Ernie

[devildog80]

Correct

Also, if you decide not to use the in tank pump, can you leave it all in the tank and just disconnect the power feed, and still be able to pull fuel through it with a lower pressure pump?
Would keep all your tank internals in place, and gauge should still read. You would only disconnect the pump power lead, which you would rewire to your new on frame electric pump.

Just a thought, as we can do that when switching from mechanical to electric pumps.

[Warlordsix]

Possible, I suppose, but I suspect I can just remover the in-tank pump and leave the fuel sender in place. I'm planning to use the stock, mechanical pump.

Ernie

[devildog80]

Then you would need to replace the in tank pump with a pick up tube, as the sender is probably separate from the pump in that tank?

[Warlordsix]

Originally Posted by devildog80

Then you would need to replace the in tank pump with a pick up tube, as the sender is probably separate from the pump in that tank?

Right. In my experience with other fuel injected tanks, the pump mounts to the same bracket that the sender is mounted to. My guess is the YJ tank is no different. We'll see.

Ernie

[devildog80]

Ok
Hope whatever I was babbling about helps

['89_Wagon]

Curious, why are you aiming to run a mechanical pump over an electric one? The electric one solves some issues with the mechanical type (vapor lock, leaking gas into the oil sump ect). Just to keep things simple?

[Warlordsix]

Most of the electric pumps (for various vehicles) I've purchased at parts stores in the last several years have given up the ghost in under two years. Sure, they typically come with lifetime warranties, but the fun of repeatedly draining and dropping tanks to replace yet another electric, in-tank pump wears off quickly. Much easier to swap out a mechanical pump.

Ernie