1988 Jeep Wrangler > 15 to 20 Gallon Gas Tank Conversion - Finished Feb. 12, 1999
From 1991-1995, Chrysler offered two different sized gas tanks for the Jeep Wrangler: 15 gallon and 20 gallon. On the outside, however, these two tanks were not different in size at all. I learned this the hard way after doing an engine swap. My new engine was fuel injected, therefore I needed to buy an electric fuel pump to feed it. It was recommended I get a gas tank from a later model Wrangler with a 4.0L HO engine because these tanks had a fuel pump built inside.
I bought a 20 gallon tank from a Snohomish, Washington wrecking yard that specialized in Jeeps. It came out of a 1992 Wrangler. Upon thorough inspection, it had the same dimensions as my stock 1988 tank so the wrecking yard assistant and I concluded it was a perfectly matched 20 gallon replacement.
After the installation, and finally being able to drive my Jeep with the new engine, I didn't travel more than 200 miles until the vehicle sputtered and stopped. The fuel gauge read 1/4 so being low or out of fuel never crossed my mind. But the only way it started again was by filling the tank up - with 15.1 gallons to be exact. This incident repeated just a few days later and after filling the tank with another 15.1 gallons, I knew something was wrong.
30 days had lapsed since I purchased the tank and the wrecking yard would not take it back so now I was stuck with a fake 20 gallon gas tank. But not for long.
What started out as a 20 gallon tank, became a 15 gallon tank, then ended up as a 20 gallon tank. Here's why: Chrysler only made 20 gallon tanks for 1991-1995 Wranglers. The difference in some was a small plastic vent hose that extended down into the tank which prevented more than 15 gallons being filled into them. By shortening this hose, the tank can hold the 20 gallons of fuel it was originally made to carry.
The entire conversion process is about a 60-90 minute job. I've heard its been a two hour plus task for others and the reason being they lowered their gas tank (or had hangovers). With a 2" body lift, scrawny arms, and small hands, I was able to work around the tank and hoses without any problems to speak of.
If the information you find here is helpful, then please let other Jeep owners know about it by linking to my site so others can easily find it. This information is provided at no expense to the offroad community, but because of its continually increasing popularity over the past years, I'm now asking three favors from my visitors:
I recommend reading all the information provided here before proceeding with your own gas tank conversion.
Oh yeah, one more thing. Don't hold me responsible if you don't have the same outcome as I did by following my instructions. My instructions are here for help only. Diamler/Chrysler/Jeep did not pay/authorize me to publish this information. Again, IT IS STRICLY FOR HELP ONLY. If you know of easier ways to get through some of the steps, then do as you wish, but please think of the rest of us and consider sharing your idea by emailing it to me so I can post it for others to read. If you have any questions about anything, I'll do my best to answer them. Email me at dorianj AT gmail DOT com and put the words 'JEEP WRANGLER' in the subject line otherwise I may not receive it.
