Guest Posted June 16, 2015 Share Posted June 16, 2015 Looking for advice on a strange problem. I purchased my 2000 LS a few weeks ago, it only has 72K on it and the Lexus History looks good. However I tried to fill her up the other day and as soon as the Guy (We still cannot fill our own cars in Oregon!) tried to put the gas in, it started to blow back. Further investigation revealed it was coming out of a small vent hole to the upper left of the filling pipe. He managed to squeeze a few gallons in VERY slowly and I said I would investigate the problem. The Gas Station is a new Shell and the pumps are brand new and fairly powerful. Anyway reading on here and other Forums, it seems putting fuel in can be tedious due to the neck of the filler pipe and the newer gas pumps. Anyway I decided to try again today at a different station (Mobil) Same problem? Tried moving the nozzle sideways, upside down etc. but still got liquid back out of this vent. I say liquid, because on further investigation (smell/taste) revealed it is WATER! We managed to get the tank full and the ammount of water coming back out reduced considerably as the tank filled. (I'm guessing I have seen about a cupfull during both fills. I'm sure this is not common, but The car does have VERY low mileage and I'm guessing has been standing for a large percentage of it's life. The climate here is currently dry (till September) but high humidity at night and cars left outside are wet from dew in the mornings. What do you Guys think? Do I need to have the tank pulled and flushed or is this just the EVAP system working overtime? The car runs great with no alarms of any kind, except low fuel a few days ago which started my investigation? Quote Link to comment Share on other sites More sharing options...
1990LS400 Posted June 16, 2015 Share Posted June 16, 2015 I never had a problem quickly filling the gas tank of the 2000 LS400 I sold last year. Google something like "how to clean out a clogged gas tank vent tube" and you should find suggestions and videos. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 16, 2015 Share Posted June 16, 2015 Thank You for the advice. I have just watched a video explaining how to clear/clean a Toyota Camry vent pipe and another that references problems with the Evap Solenoid., I am guessing the hole by the LS400 filler cap is AFTER the Charcoal Filter else it would just be venting vapour? If it is after then the water could have built up in the pipe from the canister over time and is only being purged now I am filling the car regularly? The fact it is being forced out, makes me think system is only blocked with water, does that make sense? Quote Link to comment Share on other sites More sharing options...
1990LS400 Posted June 17, 2015 Share Posted June 17, 2015 Who knows. Maybe it's rain water or condensation. The fuel system on the LS400 was revised for the 2000 model year. The tank capacity was 22.5 gallons previously and dropped to 21.9 gallons for the 2000 model year. It's still a decent capacity and easy to go 400 miles between refueling. It never got less than 25 mpg on 70 mph road trips in the 10+ years I had my 2000 LS but I drove it gently and used the cruise control more than most people. In no or light wind conditions on fairly level Midwest highways, it averaged between 26.9 and 27.1 mpg like clockwork. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 17, 2015 Share Posted June 17, 2015 Yes, I've found a few EVAP diagrams for older (Pre 96) 400's and a diagram for a 2000 and there are indeed quite a few changes. I think a lot was due to tighter emmission rules being introduced and mine WAS originally sold in California! However they all seem to show vent pipe from the charcoal canister runs back to the fuel tank and a further two that run directly from the tank to the outside/air. I'm tempted to try and "Top it Up" to see if I can purge any/all moisture out. I certainly do not want water floating on top of my fuel waiting for me to one day run the tank dry! :( Quote Link to comment Share on other sites More sharing options...
Clunkfish Posted June 17, 2015 Share Posted June 17, 2015 Just to say, water is heavier than fuel so the fuel will float on the water, not the other way round ;-) Quote Link to comment Share on other sites More sharing options...
Exhaustgases Posted June 17, 2015 Share Posted June 17, 2015 Some times I'd like that having them fuel it up. Other times when I have to worry about them scratching something or dripping gas on the paint under the cover then I wouldn't like that. I wonder if there are any complaints about ruined paint? If not, that is probably why they still do that. If enough people hit em up with 20,000 dollar equivalent to factory paint jobs because of ruined paint maybe then the tune would change. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 17, 2015 Share Posted June 17, 2015 Bob, strange you should mention that. The Oregon Senate is actually voting through a Bill this Fall to allow Drivers to fill their own vehicles (At last!) I think that just leaves New Jersey as the only place in the USA you cannot. Quote Link to comment Share on other sites More sharing options...
Guest Posted June 17, 2015 Share Posted June 17, 2015 Clunkfish, that makes sense particularly when you think of oil spills at sea. Would that therefore mean that if you DID have water in your tank and I'm guessing the fuel intake/pump is mounted quite low for gauge reading etc. then you would have a major disaster fairly quickly, or would there have to be a lot of water below the fuel? I've always assumed the EVAP systems had two roles, 1. To remove and recycle gas vapours to the engine and 2.. To remove excess moisture/water/condensation from above/within the fuel sytem. I'm guessing it would NOT detect any water below the tank fuel? Quote Link to comment Share on other sites More sharing options...
sha4000 Posted June 17, 2015 Share Posted June 17, 2015 Never heard of that happening but an interesting topic nonetheless. Quote Link to comment Share on other sites More sharing options...
Guest Posted January 7, 2016 Share Posted January 7, 2016 Hi All, Happy New Year! It's 6 months since I started this thread so I thought I would update. After my initial problems and investigation last Summer the problem just went away, perhaps due to more regular use of the car, the warmer summer weather or just luck? Anyway, no water coming back out of vent pipe on numerous refills. This holiday I made a couple of round trips from Oregon up to Vancouver, BC. Airport to collect family and had to drive through the Seattle rain :( Had to fill up on several occasions and, you guessed it, water burbling out of the vent hole in the upper left of the filler cap assembly? Again it was typically only about half a cupful, but is concerning as I would prefer to just have vapor/air! The car ran great 27mpg plus over 1500 miles of mainly I5 freeway cruising. No alarms, stuttering, poor starts etc. would just love to cure problem. Any new thoughts on my problem. Regards, Phil Quote Link to comment Share on other sites More sharing options...
Guest Posted August 19, 2016 Share Posted August 19, 2016 (edited) Eureka! After much investigation I have resolved my nagging "splash back" problem (Thanks to an in depth search on here!!!) See "craigamuir's" post 25120 dated Oct 28, 2005. "Last year my 2000 LS developed a problem when you tried to fill it with gas. As you pumped the gas in, much of it just sprayed back out. The dealer said that the charcoal cannister and the fuel filler valve needed replacing - $900. I paid for the repair. A few weeks ago the same problem repeated (or so I thought). I took it to a different dealer and told them it better not be the charcoal cannister or fuel filler valve. They pulled the shop manual on the car and began to search for the problem. 4 days later they called to say that they had solved the mystery. Apparently there's a rear drain hose for runoff water around the trunk area. The air release for the gas tank also vents into this drain line. Putting gas in the tank vents the air in the tank into the drain line. If the drain line gets clogged as mine was, the venting air causes the backed up water to gurgle and then spray out a drain hole just above and to the left of the main fuel filler hole. This makes it look like gas is coming back out when you put it in. Actually it's the backed up drain water in the line. The second dealer blew out the obstruction in the drain line with an air hose and now the car seems fine. The dealer said that they had never encountered the problem before." Note: The tank venting pipe actually feeds charcoal canister then joins vent/drain pipe to prevent any gases reaching outside (which would be illegal). I cleared debris from my drain pipe and issue solved! Seek and Ye shall find :) Edited August 19, 2016 by Guest Produced a diagram of how venting is connected around filler cap. Quote Link to comment Share on other sites More sharing options...
Chris in CA Posted October 19, 2016 Share Posted October 19, 2016 This was exactly my issue, thanks! This saved me a dealer visit, stress and $$$. All I had to do was blast a little air into the lower drain hole while plugging the upper vent hole with a finger. Water immediately drained out the line. Prior to that I could see standing water inside the vent hole, indicating there was water in the drain system. I had the same symptoms - liquid shooting out the upper vent hole, which I never even knew existed until it announced itself wetly. I couldn't see much at the gas station at night so went home with barely any gas. I'd let the tank get lower than normal - maybe 80 miles range. We just had the first storm of the season so some crud probably plugged the drain hose. Thank goodness for your answer and Google search. Quote Link to comment Share on other sites More sharing options...
Guest Posted October 20, 2016 Share Posted October 20, 2016 Glad to help, this Forum is GR8 for saving $$$ :) Quote Link to comment Share on other sites More sharing options...
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