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ncmountainbeeman 03-01-2012 06:56 PM

Fuel smell need help 1998 tj
hello all,
i have a 1998 jeep wrangler tj and it has a heavy fuel smell
no leaks anywhere and doesnt blow smoke while driving
on deceleration only i can hear a small popping in the exhaust not a big backfire just small putting sound

any help would be much appreciated

Abnmarine 03-01-2012 06:58 PM

How is your fuel mileage? Has there been a recent decrease? Could be the cat going bad.

ncmountainbeeman 03-01-2012 07:08 PM


Originally Posted by Abnmarine (Post 2092414)
How is your fuel mileage? Has there been a recent decrease? Could be the cat going bad.

hey abnmarine semper fi i just got back from 4 years as a contractor in iraq former marine 1979-83

i didnt know the cat would do that it does have 146000 on it so i guess im due lol thanks for the info

Abnmarine 03-01-2012 07:30 PM

Semper Fi

I'm not saying that is the cause but if fuel mileage has decreased combined with the popping exhaust it's a possibility.

Jerry Bransford 03-01-2012 07:34 PM

My first guess would be a bad upstream 02 sensor. Your '98 has more than enough miles on it to by now need new 02 sensors (your '98 has a total of two 02 sensors). When the upstream 02 sensor (mounted just below the exhaust headers) goes bad, it often erroneously signals the computer the air/fuel ratio is too lean... which causes the computer to enrichen the air/fuel ratio way beyond what it should be. That air/fuel ratio is often so rich you can smell it. Plus it will cause the engine to run like crap.

To save $$$, I'd start by replacing just the upstream sensor. On early TJs like yours, the upstream 02 sensor is the one that the computer uses to monitor the air/fuel ratio.

ncmountainbeeman 03-01-2012 07:35 PM

thanks ill check it out

G54 03-01-2012 07:58 PM

Is your check engine on? My upstream O2 just went bad on my '99 but it lit up my check engine light which tipped me off before any other bad symptoms showed up.

But I think I've heard that it doesn't always trip the light.

Jerry Bransford 03-01-2012 08:06 PM

A bad 02 sensor, especially on earlier model year TJs, will not often generate a Check Engine light. Early TJ engine computers have a tough time determining if the 02 sensor is feeding it bad info.

ncmountainbeeman 03-01-2012 08:56 PM

there is no check engine light but i believe it is the o2 sensor the symptoms are what was described thanks a bunch guys!

IslandTJ 03-02-2012 12:37 PM

Jeep used to have a strong fuel odor, especially after a fill up. Turned out to be a loose collar on the fuel tank. I didn't find out until I dropped my tank to install my gas skid.

LOL, the dealership told me at the time that the tank "needed" replacement and that they would easily do it for $650 :eek:. I'm glad I turned the recommendation down and troubleshooted myself. Didn't cost a dime to tighten the collar :).

badlittlemunky 11-03-2012 09:46 PM

I had similar symptoms and more--powerful gas smell, popping, sputtering, flat-out backfires, hesitation, smoke on start up, high idle, absolutely awful gas milage... But, no check engine light. Based on what I read in this thread, I decided to replace the upstream O2 sensor and do a quick tuneup. All the symptoms are gone. I'm positive that the O2 sensor isn't the only cause of the smoke and idle issues and will be paying close attention to see if those or any of the other problems come back. For now, things are really good. Cheers, all.

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