eaglescout526 Posted January 28, 2020 Share Posted January 28, 2020 Alright like the title says I have been battling this problem since I got LR. I have replaced the vents on top, the sending unit O-ring and an emissions hose. I have no idea what else to loom at or replace. I have even blown out the lines that go to the vents on top of the tank and the gas still over flows. Any suggestions? I vaguely recall someone blaming GM on this issue but don't remember. Link to comment Share on other sites More sharing options...
Ωhm Posted January 28, 2020 Share Posted January 28, 2020 Don't filler neck have two (2) tubes going to the tank. One being a vent, the other for fuel fill. Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 28, 2020 Author Share Posted January 28, 2020 That is correct. I have heard they can kink but I have removed the tank only once(during the get her running phase) and it has always done such. Maybe I did kink the vent line? Link to comment Share on other sites More sharing options...
Ωhm Posted January 28, 2020 Share Posted January 28, 2020 Kinked or plugged. Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 28, 2020 Author Share Posted January 28, 2020 Well that's one possibility I will check for this weekend. Ill probably remove the filler assembly anyways to clean it up. Any other possibilities? Link to comment Share on other sites More sharing options...
Ωhm Posted January 28, 2020 Share Posted January 28, 2020 Try another pump nozzle. Link to comment Share on other sites More sharing options...
eaglescout526 Posted January 28, 2020 Author Share Posted January 28, 2020 Lol! I even tried the first latch on the nozzle to slow down the flow rate and it still did it. Guess I could just stand there and hold it until it fills up. But I just can't imagine this being a huge issue back then. Link to comment Share on other sites More sharing options...
CODriver Posted February 1, 2020 Share Posted February 1, 2020 I've got the same overflow problem, if you solve it let me know. Link to comment Share on other sites More sharing options...
eaglescout526 Posted February 1, 2020 Author Share Posted February 1, 2020 I have not. I even went as far as taking the charcoal cannister apart and no dice there. Then I tried blowing in the lines with compressed air and down the filler neck it spit fuel back up but down the air side it did not. I believe the baffle is a problem in the tank. Link to comment Share on other sites More sharing options...
Ωhm Posted February 6, 2020 Share Posted February 6, 2020 Using your Sales Code Decoder per VIN (nice job by the way), three (3) different size Fuel Tanks (gallons) show up. 18.5, 20 & 23. Do all three tanks use the same filler neck? I'm wondering if there could be a mismatch between Tank size and Filler Neck. Link to comment Share on other sites More sharing options...
eaglescout526 Posted February 6, 2020 Author Share Posted February 6, 2020 No. The catalogue is showing me that all years use the same part number. As far as I know my truck is pretty unmolested which is nice. I haven't replaced the filler neck tubes. The only thing I can think of is the baffle but I can't find any info on the baffle being an issue for the tanks and the tank I have is an original 16 gal tank. Link to comment Share on other sites More sharing options...
Ωhm Posted February 6, 2020 Share Posted February 6, 2020 Funny how no 16 gallon tanks have showed up yet, but I've only look at 25 VINs. Link to comment Share on other sites More sharing options...
eaglescout526 Posted February 6, 2020 Author Share Posted February 6, 2020 Well wasn't there 3 tank options? 16 for the typical base/economy package for the LWB, 23.5 was optional and 18 was SWB. 20 gal should be an XJ tank capacity I thought. Link to comment Share on other sites More sharing options...
Ωhm Posted February 6, 2020 Share Posted February 6, 2020 Don't know Parts. My train of thoughts was larger tank might need shorter fuel filler neck or vice a versa. Link to comment Share on other sites More sharing options...
eaglescout526 Posted February 6, 2020 Author Share Posted February 6, 2020 I see what you're saying. But nope the filler neck is same for all MJ years and mine is in good shape minus the flap not pressing up against the filler hole. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 4, 2020 Author Share Posted March 4, 2020 Well I have no idea why this happens. I am willing to bet it is due to the pressure rate in which the pump dispenses fuel. Anyways I removed the sending unit last night from the tank to see if there was any obstructions to the baffle or vents and I found nothing other than slight rust. So I filled up this morning and listened closely to when the fuel was gonna come back out. All the vent lines are clear and every seal has been replaced on the tank. Link to comment Share on other sites More sharing options...
WeezyBlue Posted March 9, 2020 Share Posted March 9, 2020 This is still an issue with Jeeps through the 2000s. Whether or not it's the same cause, I don't know, but I fixed it on my 05 TJ and my buddy's KJ Libby. There's a rollover check valve inside the tank, at the base of the filler tube. The tolerances are too tight on the spring loaded valve, and depending on temperature and humidity it can stick, causing the overflow. Solution is to reach in through the fuel pump hole, pop it out, grind down the ridges on the valve, and stick it back in. Again, don't know if that was the same issue back then, but I know it plagues Jeeps at least as far back as the 97 TJ. Link to comment Share on other sites More sharing options...
Dzimm Posted March 9, 2020 Share Posted March 9, 2020 There are no check valves on the XJ/MJ that I've ever seen. Straight through to the tank. I occasionally have it spew gas out when it clicks off after filling or the pump refuses to dispense and keeps clicking off. This ha ls all happened to both XJs and both MJs I have/had. Try putting the filler spout only halfway in the Jeep, like just far enough in that it stays without you holding it. For some reason I never have a filling issue when I do this. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 9, 2020 Author Share Posted March 9, 2020 Just now, Dzimm said: Try putting the filler spout only halfway in the Jeep, like just far enough in that it stays without you holding it. For some reason I never have a filling issue when I do this. Funny enough I think I tried that when I filled up. I got better results that time, gas still wanted to spew out but I caught it. I think it also comes down to having just replaced the sending unit seal to where now the tank is perfectly sealed and air isn't escaping out of that point. Since the last fill up I noticed I put 15 gallons in and I would say I had about 2 gallons left in the tank so I over filled, so I think it is safe to say at that fill up it clicked off right when it should've and would've read right at the "F" on the gauge. Next fill up I will have to try this theory. Link to comment Share on other sites More sharing options...
Dzimm Posted March 9, 2020 Share Posted March 9, 2020 2 minutes ago, eaglescout526 said: Funny enough I think I tried that when I filled up. I got better results that time, gas still wanted to spew out but I caught it. I think it also comes down to having just replaced the sending unit seal to where now the tank is perfectly sealed and air isn't escaping out of that point. Since the last fill up I noticed I put 15 gallons in and I would say I had about 2 gallons left in the tank so I over filled, so I think it is safe to say at that fill up it clicked off right when it should've and would've read right at the "F" on the gauge. Next fill up I will have to try this theory. Just so I can fully understand the problem you are having, is the pump not clicking off at all, like it will just pump gas on the ground? Or does it do like mine and puke gas out when it clicks off? Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 9, 2020 Author Share Posted March 9, 2020 Just now, Dzimm said: Just so I can fully understand the problem you are having, is the pump not clicking off at all, like it will just pump gas on the ground? Or does it do like mine and puke gas out when it clicks off? It still pukes out when the pump clicks off, which has been the issue for forever. I haven't had a pump keep pumping when it is full. Link to comment Share on other sites More sharing options...
Dzimm Posted March 9, 2020 Share Posted March 9, 2020 1 minute ago, eaglescout526 said: It still pukes out when the pump clicks off, which has been the issue for forever. I haven't had a pump keep pumping when it is full. Yeah try the sticking out part way and see what happens. Hopefully it works for you. Link to comment Share on other sites More sharing options...
eaglescout526 Posted March 9, 2020 Author Share Posted March 9, 2020 Will definitely give it another shot next time! Thanks Dzimm! Link to comment Share on other sites More sharing options...
Ωhm Posted March 9, 2020 Share Posted March 9, 2020 On 1/27/2020 at 8:32 PM, eaglescout526 said: Any other possibilities? At the charcoal canister remove the vent line from the fuel tank and let it vent to air. Try fuel fill that way. Link to comment Share on other sites More sharing options...
Jaime Posted May 22, 2020 Share Posted May 22, 2020 Found your post. Can’t wait until the next time I need to fill up. I’ll try the spout partially out next time. Any thing to try and stop it. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now