Fuel tank swap

[vlad588]

I’m thinking about swapping fuel tank in my 03 KJ, replacing 18.5 gallon with a 20.5 gallon one from 07 Liberty. I’m wondering about compatibility of the two, has anyone done it and is there any issues with this or is it a straight swap?

 

[duderz7]

I didn't even know there were different sizes whithin the kj's...very interesting. Not sure 2 gallons would be worth it unless you just happen to have one or it needs replaced anyway.

 

[vlad588]

There is an 07 KJ at local junk yard so it be cheap to get. My range has suffered a fair bit after adding steel bumpers, skid plates ext, so i’m trying to get as much fuel reserve as possible, i know 2 gallons doesn’t sound like much but it can make a difference when on the trail.

 

[klc]

My 06 Limited has a 21 gallon tank. It can consume mass quantities of dollars.

 

[lfhoward]

My 08 has a center mounted 19.5 gallon tank and a spare tire where the KJ fuel tank was in the rear. I have always wondered if it would be possible to install a KJ tank (and skid plate of course) and use it as an auxiliary tank that can feed the main one. I think the safety factor is the main thing keeping me from DIY-ing this. I have lots of good junkyards in my area so parts are widely available.

 

[dtennes]

Things to look out for:
1. Fuel delivery plumbing. 2002-2004 definitely has a fuel pump *inside* of the tank with an external connector back to the PCM, fuel filter outside with 2 specialized fuel line connectors, and a leak detection pump with a connector back to the PCM. IOW, specialized wiring and connectors that may not match models after 2004.
2. Electrical connections from fuel pump to the PCM. The PCM for 2005+ is redically different from 2002-2004. No signal, no fuel.
3. If you get a tank from a salvage yard, the yard may drain the original tank by augering a hole... which is what they do around Atlanta anyway. Not sure what the tank is made out of, and some plastics can be a challenge to patch.
4. Mounting staps. The 2002-2004 has 2 wrap-around straps that are specific dimensions designed for the tank for those years. Other tanks may have different shapes and therefore different alignment and tolerances when mounting and securing.

 

[dtennes]

Ok... the preceding post was "stream of consciousness". Disregard. I looked up the fuel pump for a 2007, and my advice is now: "don't mix and match tanks". If you have a fuel pump problem, (a) buy a new locking ring Mopar 52100409AB because the old one is probably rotted, (b) buy a Crown Automotive fuel pump, (c) keep and clean out the original tank, (d) buy a new fuel filter (also Crown) and replace the old one while the tank is down.

That way there is no guessing/hacking nonsense with wiring back to the PCM.

 

[vlad588]

Ok... the preceding post was "stream of consciousness". Disregard. I looked up the fuel pump for a 2007, and my advice is now: "don't mix and match tanks". If you have a fuel pump problem, (a) buy a new locking ring Mopar 52100409AB because the old one is probably rotted, (b) buy a Crown Automotive fuel pump, (c) keep and clean out the original tank, (d) buy a new fuel filter (also Crown) and replace the old one while the tank is down.

That way there is no guessing/hacking nonsense with wiring back to the PCM.

Thanks for the advice. I will probably abandon the tank swap idea as it doesn’t seem to be far too complicated for the small fuel capacity i would gain. Instead i’ll try to build a rear side window fuel can mount for extra storage.