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?
Fuel tank swap
- Thread starter vlad588
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duderz7
Full Access Member
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.
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.
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.
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.
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.
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.
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.
