Announcement Announcement Module
Collapse
No announcement yet.
CJ 7 Gas Smell Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • CJ 7 Gas Smell

    Have a reasonable gas smell seems to happen most often without pressure on gas pedal, ie. idle speed or slowing to stop, coasting. Just had intake, exhaust manifolds and carburetor replaced. Any ideas. Thanks

  • #2
    Past Jeep Options...

    Recently we discussed the automatic rust inhibitor system installed by AMC on the CJ. There was also an unburned fuel aroma injection (UFAI) system available back in the day. It is a dual injection system that operates on the draft principle whereby all fuel fumes are directed toward the interior of the Jeep from beneath the hood and from the exhaust. This system was expensive. It cost pretty much the same thing as the Jeep and was purchased mainly by Jeepers who wanted to be reminded by the heavy gas smell that clung to their clothes all day that their four wheel love waited patiently in the parking lot for their return. It also has the added benefit of pleasing girls who have never been on a first date in a CJ equipped with UFAI.

    The automatic rust inhibitor system can be disabled with a generous application of maintenance effort, new gaskets and seals.

    The UFAI system is a totally different story. Once it has been installed it is very difficult, if not impossible to remove. Some theorize that older CJs simply won’t run without it. In order to prove this theory one only has to sit in his or her beloved CJ without the motor running. Notice how much cleaner the air smells?

    Man… I took a long time GOOFING with you on that one didn’t I? I guess I got to enjoying myself. Rerouting of the exhaust ‘might’ alleviate a majority of the gas ‘smell’ if you were talking about ‘smell’ as in exhaust. If you have a strong ‘raw’ gas smell it sounds like something might be leaking. Have you checked your new carburetor and associated tubing? Oh, and WELCOME to the board!

    Comment


    • #3
      Is it any different with a full tank or a half empty tank? It could be the "System Maintenence" notification AMC used on these jeeps. Unlike the newer "maintence lights" found on the dash of newer cars, AMC designed the float level sending unit to slowly self destruct so at the appropriat time you will have to remove the fuel tank and replace all the fuel lines while you inspect the rear of the frame for rust problems that could lead to a dangerous situation.

      AMC knew that lights can burn out and you would never think of checking on these simple maintenece items by yourself so they whent with a ofactory notification system. You may never hear a buzzer with the top off or see a light in the sunlight but you cant mask that smell.

      Comment


      • #4
        That was pretty awesome Blackwater. I personally would check connections and such to make sure things are tight. Or, I would simply take it back to whoever worked on it and tell them to fix it.

        High5

        Comment


        • #5
          i am trying to limit the smell from my cj5 for my kids sake. my cj currently has straight pipes on it. the draft from the jeep sends the fumes right in the back and on top of the kids.

          i am rerouting the tailpipe to behind the rear wheel and hopefully the draft from the tires send the fumes away. if anyone else has tried this with success please let me know. if it didnt help please let me know asap so i dont waste my time.

          Comment


          • #6
            exhaust routing...

            Originally posted by oxcj5
            ...if anyone else has tried this with success please let me know. if it didnt help please let me know asap so i dont waste my time.
            Ox, not quite but close. I rerouted to exit before the rear tires. This had a 'noticeable' effect but I still get exhaust fume incursion when running without a top. It's really pretty bearable. The problem with my routing is if you do the rocks it's going to cause clearance troubles at some point. Gnarly posted some pics some time back of his routing which is basically the same if you'd care to search his posts.

            Thanks, High5. John didn't do too bad, either... I like the 'self-destructing sending unit'. AMC engineers were BRILLIANT... simply BRILLIANT!

            Comment


            • #7
              I think yins are on the right track, but the exhaust was not the source of the gas smell on my CJ. If you think about it, exhaust doesnt smell like pure gas, and the smelly smell that I smelled was just as smelly as if I was pumping gas when I was stopped. I never smelled anything while moveing, even with the top off. It ended up being the charcoal canister. There is a vent on the gas tank that hooks up the the canister to remove excess fumes from the tank. When I had a full tank, and was going up /down steep inclines, the suction from the canister was enough to actually suck gasoline from the tank, and saturate the fibers in the canister. Sometimes gas would even drip from the bottom of it. I simply disconnected the line from the canister that ran back to the tank, capped the spout on the caniser, and plugged the tube going to the tank with a 3/8 bolt and a hose clamp. FIXED! well for the most part. It does still have a stench, but only when I turn off the motor.

              Comment


              • #8
                Mine's good with turn downs on the ends. With the top off, I never get any fumes.

                High5

                Comment


                • #9
                  ....took a long time GOOFING with you on that one didn’t I? I guess I ‘smell’ as in exhaust. If you have a strong ‘raw’ gas smell it sounds like something might be leaking. Have you checked your new carburetor and associated tubing? Oh, and WELCOME to the board![/QUOTE]


                  Man I was really enjoying the story, while writing the for sale ad....
                  Had the carb and all the connections checked about 3 times, my next thought was a gas tank leak, hadn't thought about checking the exhaust pipe, just didn't know if there was some sort of back pressure issue, since it only seem to happens when I back off the gas. Gonna check routing the tail pipe.
                  Thanks

                  Comment


                  • #10
                    Originally posted by High5
                    Mine's good with turn downs on the ends. With the top off, I never get any fumes.

                    High5

                    DITTO on the turn downs.
                    But I thought the fumes were a mosquito deterant while at a stand still. A thoughtful feature for an open air vehicle.

                    Comment


                    • #11
                      If I overfill the tank, keep adding gas after it has clicked off once. I get fumes from hell, the overflow backs up and ends up in the charcoal cannister. May or may not help with yours but it is worth checking.

                      Comment


                      • #12
                        I've had various raw gas smells from mine over the years. One was a bad fuel pump. One was a leaking carb. The other was that the gas tank would leak badly out of the top if it approached being topped off.

                        Fixed all of those now I just get the aforementioned exhaust smell but I'm used to it so I don't notice it. The wife however knows when I've been driving as "I smell like the Jeep".

                        Comment

                        Working...
                        X