1988 Jeep Wrangler > 15 to 20 Gallon Gas Tank Conversion - Finished Feb.
12, 1999
UPDATE: You can now read about this conversion over at the Wrangler YJ web site.
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 wrecking yard that specialized in Jeeps. Its
original home was 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 guage 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 so the wrecking yard would not
take it back. And 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it was originally made to carry.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 it’s
been a two hour plus task for others and the reason being they lowered their
gas tank (or had tequilla shots prior to). 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.
Let's begin
