88whitemanche Posted August 28, 2013 Share Posted August 28, 2013 What's up guys Lately the truck has been running great no issues except that I've noticed my gas has been going fast than normal. I do mainly highway miles so it shouldn't be much if an issue....so lately I've been noticing that when I put gas or when I'm idling I'm smelling unburnt fuel... is there anything I can do to diagnose this? Link to comment Share on other sites More sharing options...
mpace6a Posted August 28, 2013 Share Posted August 28, 2013 Check for leaks. Happened to me and I had a leaking fuel line in the engine bay. Usually gas evaporates fast enough you won't notice a leak, but drive somewhere, and when you smell gas pull into the nearest parking lot, pop the hood, look for wet areas, and check the lines from the tank to the engine bay. Link to comment Share on other sites More sharing options...
AeroNautical Posted August 28, 2013 Share Posted August 28, 2013 To add on to mpace6a: If it's a leak, FIND IT FAST. I had a fuel line leak into the fuel rail, the o ring was bad. It happened to be the exact time I had a wire shorting somewhere in the engine bay. Electrical fire plus gasoline means a bad time. Dedicate some time in your day to finding and fixing it. Take a day off of work if you have to. Your life is worth more than a day of pay. Though it might sound like it, I'm not overreacting. It's literally a time bomb until you fix it, can't stress this enough. Link to comment Share on other sites More sharing options...
MancheKid86 Posted August 28, 2013 Share Posted August 28, 2013 02 sensor? Link to comment Share on other sites More sharing options...
cruiser54 Posted August 30, 2013 Share Posted August 30, 2013 What's up guys Lately the truck has been running great no issues except that I've noticed my gas has been going fast than normal. I do mainly highway miles so it shouldn't be much if an issue....so lately I've been noticing that when I put gas or when I'm idling I'm smelling unburnt fuel... is there anything I can do to diagnose this? Do this regardless: Renix Ground Refreshing The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily. The components grounding at the dipstick tube stud are: Distributor Sync Sensor, TCU main ground, TCU “Shift Point Logic”, Ignition control Module, Injectors, ECU main ground which other engine sensors ground through, Oxygen sensor, Knock Sensor, Cruise Control, and Transmission Sync signal. All extremely important stuff. The factory was aware of the issues with this ground point and addressed it by suggesting the following: Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Must be clean, shiny and free of any oil, grease, or paint. Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Reinstall all the wires to the stud and tighten the nut down securely. While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, and reattach securely. Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for it’s intended use and subject to corrosion and poor connections at each end. First off, remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Reattach securely. Remove the other end of the cable from the rear of the head using a 3’4” socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely. A suggestion regarding the braided cable: I prefer to add a #4 Gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18” long with a 3/8” lug on each end works great and you can get one at any parts store already made up. Napa has them as part number 781116. A further improvement to the grounding system can be made using a #4 cable, about 10” long with 3/8” terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. Napa part number 781115. For those of us with Comanches, it’s very important to remove the driver’s side taillamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Reattach securely. If you want to upgrade your grounds and battery cables in general, contact Jon at www.kelleyswip.com. He makes an incredible cable upgrade for a very reasonable price. Revised 03-04-2013 Link to comment Share on other sites More sharing options...
88whitemanche Posted August 30, 2013 Author Share Posted August 30, 2013 Cruiser I have already done your ground refreshing...but I did notice today while looking into my engine bay that the ground by the back of the head that attaches to the fire wall of the engine bay is filled with oil and muck from my previous plastic VC and rubber gasket....since I've upgraded to the aluminum VC and pre molded 98 Dakota gasket....it hasn't leaked a single drop.... But I haven't cleaned up since then...I will do refresh my grounds again Saturday This Saturday I will be cleaning that area as well as the dipstick ground also.... Link to comment Share on other sites More sharing options...
cruiser54 Posted August 30, 2013 Share Posted August 30, 2013 Excellent plan. Don't be shy about adding extra grounds per my write-up. Link to comment Share on other sites More sharing options...
88whitemanche Posted November 13, 2013 Author Share Posted November 13, 2013 To bring this thread back to life...I've done the grounds refreshing again and no more unburnt fuel but now I'm getting a loud popping noise....sounds like a muffled back fire.... First time at a light at idle I thought it was someone popping a paper bag but I heard it on the hwy decelerating today and it's the same noise that I heard the other day.... Also noticed lately my water temp haven't been getting up to temperature lately it's been at about 140-150 degree range...I live in miami so cool weather is at about 75-80 degrees/windy Could it be that the water temp. Not getting up to spec that it's dumping more fuel and causing the backfire? Or the o2 sensor may be going out as well? Link to comment Share on other sites More sharing options...
carnuck Posted November 20, 2013 Share Posted November 20, 2013 Cat ratting? Sounds like popcorn almost. Injector sticking open? I re-did my thermostat and almost forgot to bleed the system by unscrewing the temp sensor. Link to comment Share on other sites More sharing options...
88whitemanche Posted November 20, 2013 Author Share Posted November 20, 2013 The cat is not rattling but it did backfire again today decelerating with the truck in gear. I was with a buddy of mine that we car pooled to work today and he literally jumped out his seat because of it. Then while at the light at idle after the backfire my idle was extremely low right in the 100 area and it did sound like popcorn popping. But after 20seconds the idle went back to normal and the popping stopped. So I arrived at work decelerating again and no back fire. I was sitting at my parking spot at idle and no popping or anything. Even checked the muffler and cat to see if it exploded and no signs if any damaged. Even looked inside my tailpipe and no signs of black smoke or residue Link to comment Share on other sites More sharing options...
carnuck Posted November 20, 2013 Share Posted November 20, 2013 Check the dist cap fro moisture and/or crossfiring. Link to comment Share on other sites More sharing options...
88whitemanche Posted November 20, 2013 Author Share Posted November 20, 2013 I will check the distributor cap when I get a chance today after work and I've done a little bit of research here in the forum and all signs seem to be pointing at the o2 sensor... So far this backfiring is only happening in the mornings when it's cool and when in gear(ax5) decelerating from 70 down to complete stop...I normally put the truck in neutral rolling to a complete stop but to pin point the backfire I've been leaving it in gear.... Link to comment Share on other sites More sharing options...
88whitemanche Posted November 30, 2013 Author Share Posted November 30, 2013 Well just to update this thread I checked the dist. Cap and clean as a whistle and no moisture I happened to change the o2 sensor and a 195degree thermostat compared to the 160 degree I had before and the truck idles flawlessly and no rich mixture smell anymore!!! Will know more about the backfire in the coming days but so far fixed!!!!! Whoo hoo and a pic of the old o2 sensor! Filthy! Link to comment Share on other sites More sharing options...
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