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Eurovan Gasoline Fumes when Hot & High - Recap
开云体育
Even if you built up 20-30 psi in the tank, it is not that much volume. And the fact that the pressure keeps buildup after turning off engine You can get an infrared temperature gun and measure the outside of the tank I would love to get a temp probe in the tank, but not possible How close does your exhaust pipe run to the tank? BTW, ?I remember this issue from several years from a guy going to Yellowstone? Stephen? |
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Bishop is probably about 5,000 people but yes, they get a lot of people passing through. It's an hour before Mammoth from LA/SoCal. I always run Premium and did in Bishop, as well as Gardnerville, but in Gardnerville they had 4 grades of octane and I chose the 3rd ( can't remember the rating). The highest was 100 octane, and expensive, something like $7.75. I don't have any idea how many people buy Premium. I would guess not many. David
On Saturday, July 15, 2023 at 06:18:16 PM PDT, Stephen Jackson <register@...> wrote:
How big is Bishop?? Do they get a lot of traffic? Do you fill up with Premium? What I am wondering is if their Premium tank does not need to be refilled very often and still has winter mix in it Stephen |
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Has anyone experiencing these EVAP/vapor lock/whooshing/boiling symptoms noticed that their fuel tank capacity has reduced over time? Could it be that instead of pressure buildup, it's a vacuum that sucks in the walls of your tank. On my previous 92 Eurovan I had these problems. My mechanic removed the gas tank and it was shrunken. It made sense because over time I was finding I couldn't get as much gas in and my range was reduced from when I first got it. Or has the shrinking taken place when it cools down with some kind of vacuum happening. I'm curious if anyone experiencing this would notice a bulging or shrinking if they visually check in the moment.
Knock on wood, I don't have this problem with my current 92. I'm religious about not overfilling as that is what I believe causes this. Brian Chisholm Vancouver BC 1992 Westfalia camper 2.5 5 speed manual 280,000 kms -- Brian C.?? Vancouver BC 92 Westy EVCamper |
开云体育Excellent commentary everyone!Cold Temperature + Higher?Altitude:?The next morning, I drove from 7500', dropping down to about 7000', then up to the pass at Conway summit, which is about 8200'. ?This was about an hour's drive. ?Stopped the van at the summit to check, engine on, removed the cap: zero pressure. ?Turned off the engine. ?Still no pressure. ?Measured the external tank temperature about 85F, internal gasoline temperature was about 65F. ?? I conclude from this that the problem requires heat + temperature, and is consistent with the theory that the gasoline is in fact vaporizing, perhaps on the round trip through the fuel pump to the engine. Gasoline / Tank status: ? I generally have this problem when I fill up in the eastern sierras, specifically Bishop, or in this case Big Pine. ? In either case, the gas tank is mostly full when I'm having the issues (perhaps 85% to 90% full). ? ?I, too, am suspicious that perhaps these little towns are still selling winter blends in the summer. Performance / Codes: ?I have no CEL light and VCDS shows no codes. ? The tank fills normally and appears to contain the right amount of fuel when full. Time to release vapors: ?I've definitely had it take minutes for the vapors to release - remember there is a filler flap which remains closed, blocking most of the opening to the tank. E10 vs E0.? ?I saw a place advertising 0% ethanol gasoline down near Carson City - I'm tempted to fill up there on the return trip, and see if the problems recur.
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开云体育I conclude from this that the problem requires heat + temperature,? Sorry, typo: I meant that I conclude from this that the problem requires heat + altitude,? |
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More musings...
David and my experiences run in parallel: - both driving 2000 EVCs up the 395 - filling up in small towns with Premium 91 octane - having tremendous fume release with heat + altitude - pressure is taking literally minutes to release all the fumes But some notable differences - David is reporting drivability issues: "Had a really hard time pulling up Sherwin summit on 395 and again up to Convict Lake." My van drives fine. - David is having problems at 4000' elevation: "When I stopped for gas in Bishop the tank released pressure for about 10 minutes". My van is fine at 4000' but I did have problems at 6000' and 7500' when hot (but not at 8200' when the gasoline was cold) - My van has a brand new GM vapor canister retrofit, David's is presumably stock. - My van has a brand new N80 and all lines are clear (not sure about David's) - After venting, my van will immediately create more pressure with the engine running which stops when the engine is off (I don't think David tested this). How to make sense of this: - the root cause is the same - "bad" gasoline (E10, or perhaps E10 in a winter blend) + heat + altitude is boiling the gas on the round trip to the fuel pump, leading to a tremendous amount of vapor. - in David's van, with the stock Vapor canister, the system gets quickly overwhelmed so he's venting at 4000' - in my van, the new GM vapor canister does a better job, but eventually gets overwhelmed and vents at 6000' - something is causing the N80 system to not work well, so not enough vapor is getting purged Theory: Gas is boiling on the round trip via the fuel pump. We are both having some ECU issue, such as MAF or Oxygen sensor issues. The van thinks the mixture is too rich, and therefore is keeping the N80 mostly closed. So even though the N80 system is in good mechanical condition, it's not being commanded to work properly, and not enough vapor is getting purged. I have a VCDS in the van - is there any way to test this theory? |
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To muddy (or hopefully maybe) clear the waters a little more: I had my test of the spring breather bend/new gas cap last Sunday. Short version- it was mixed. Longer version- It's finally hot in Truckee/Tahoe. Drove around Truckee noonish with no problems (on mostly empty tank), no pressure build up. Put 6 gallons in tank for trip to Reno. No problems at all, including no pressure, in drive to Reno and driving around Reno which was very hot, and included a lot of parked with the engine running (dog). Leave Reno and fill tank, with Premium, at a Chevron, on the outside side of town. Again, after all that hot, hot driving around Reno when stopping to fill up, there was no pressurization. Then we pull the 80 back to Truckee with no missing/stumbling make 1 stop in Truckee and at the 2nd stop I smell heavy gas odor and have small engine miss/skip. Stop and tons of pressure in tank. I rebend the filler spring (not sure how far to bend it and am cautious about F'ing it up), Next couple days driving around are mixed- a little gas smell and a little pressure and very slight engine skip. It was fine yesterday on drive half way around Tahoe. That's all I got, but I don't have anything consistent to point to except maybe the gas make-up and/or quality (which I have not been noting), combined with heat, and maybe at 4000' elevation. And maybe having a full tank. David
On Thursday, July 20, 2023 at 08:19:59 AM PDT, Michael Diehr <md03@...> wrote:
More musings... David and my experiences run in parallel: - both driving 2000 EVCs up the 395 - filling up in small towns with Premium 91 octane - having tremendous fume release with heat + altitude - pressure is taking literally minutes to release all the fumes But some notable differences - David is reporting drivability issues: "Had a really hard time pulling up Sherwin summit on 395 and again up to Convict Lake."? My van drives fine.? - David is having problems at 4000' elevation: "When I stopped for gas in Bishop the tank released pressure for about 10 minutes".? My van is fine at 4000' but I did have problems at 6000' and 7500' when hot (but not at 8200' when the gasoline was cold) - My van has a brand new GM vapor canister retrofit, David's is presumably stock. - My van has a brand new N80 and all lines are clear (not sure about David's) - After venting, my van will immediately create more pressure with the engine running which stops when the engine is off (I don't think David tested this). How to make sense of this: - the root cause is the same - "bad" gasoline (E10, or perhaps E10 in a winter blend) + heat + altitude is boiling the gas on the round trip to the fuel pump, leading to a tremendous amount of vapor. - in David's van, with the stock Vapor canister, the system gets quickly overwhelmed so he's venting at 4000' - in my van, the new GM vapor canister does a better job, but eventually gets overwhelmed and vents at 6000' - something is causing the N80 system to not work well, so not enough vapor is getting purged Theory: Gas is boiling on the round trip via the fuel pump.? We are both having some ECU issue, such as MAF or Oxygen sensor issues.? The van thinks the mixture is too rich, and therefore is keeping the N80 mostly closed.? So even though the N80 system is in good mechanical condition, it's not being commanded to work properly, and not enough vapor is getting purged. I have a VCDS in the van - is there any way to test this theory? |
开云体育Doing the reverse drive south on 395, I filled up with no-ethanol 91 octane at the WalMart Supercenter in Gardnerville NV, and started the climb into the sierras with about the same conditions as the northbound trip: 90F+ temperatures, tank about 1-2 gallons below full. ? Absolutely no fumes or pressure this time, checked at 6000' and 8000' elevations. ? Gas temperature was about 115F, which is not quite as high as the 120F on the northbound trip.
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I just drove from MA to OR. 1995 EVC, mt. Four days. Mpg varied: 18-29. One 86 mile stretch was 14 mpg. Nothing to distinguish why. On the last day I drove from Bozeman to Portland over Lolo Pass. The temperature in eastern?Washington was 103. Filling the tank became problematic due to off-gassing.? That said the van performed pretty flawlessly. Ten thousand miles down. We'll see how it goes from here.? On Fri, Jul 21, 2023 at 8:40?PM Michael Diehr <md03@...> wrote:
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Wow what a wild ride! Fuel initial boiling point is 95 °F (35 °C) at sea-level. Fuel boiling point inversely proportional to elevation. Winter blends have lower boiling points than summer blends. Vapor created at boiling point. Lean fuel trim means more air entering intake than ECM expects (ECM adds fuel by pulsing injector/spark more). ? Rich fuel trim means less air entering intake than ECM expects?(ECM subtracts fuel by pulsing injector/spark less). ? |
开云体育Thanks, Duane!?For anyone reading this document, please note that the early pictures don't tell the whole story. ?You must read through to page 26/27, where the On-board Re-Fueling and Vapor Recovery system (OVRV) is introduced. ?The document notes this was introduced in "1998" and given model year lag, I wonder if in fact this only showed up in 1999 or perhaps 2000 eurovans? ? If you read about this vapor / fume problem, it seems the vast majority of us suffering it have 2000s. ?The evap system was redesigned for the 2001-2003 years, which don't seem to suffer this issue as much or at all. In particular, I wonder about the Pressure-Holding Valve (PHV) which is described thus:
(Emphasis mine) This suggests to me another scenario: - maybe the PHV has a failure mode - some combination of pressure (internal gas vapor pressure, and external atmospheric pressure) in which it gets stuck in the closed position. - vans before1999 (?) ?don't have the PHV ?only 2000 year vans do. ?2001 and later have a redesigned system. ?This could explain why it's so common for us 2000 owners but not before or after.
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An update to the saga - my 2000 EVC is at the mechanic, who just did a smoke test where they pressurize the evap system and gas tank with smoke. They have found a small leak which appears to be coming from on top of the gas tank, but were unable to determine the precise source of the leak.
The next plan is to drop the tank and do more testing. This finding seems consistent with the symptoms: if there is some sort of small crack in one of the plastic or rubber parts, it could leak only when the pressure difference is extreme (e.g. heat + altitude, possibly made worse if the N-80 or evap canisters are clogged, or the gasoline has a high RVP). I'll report back when I hear more. |
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Geez Michael, this is a very common problem with all other old cars.? Glad you applied the muscle to it.? Thanks. On Wed, Aug 9, 2023 at 10:29?AM Michael Diehr <md03@...> wrote: An update to the saga - my 2000 EVC is at the mechanic, who just did a smoke test where they pressurize the evap system and gas tank with smoke.? They have found a small leak which appears to be coming from on top of the gas tank, but were unable to determine the precise source of the leak.? |
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Hi, Michael,
Headscratcher! I disagree. Don't believe the "leak" is consistent with the issues you've been describing (spewing fuel vapor and fuel when gas cap opened) -- with no codes (MIL). Difficult to build pressure with a leak, especially when fuel vapor whooshes out of the filler pipe with some liquid fuel. Also, after reading Brian's documentation, I?understand your van uses pressure to test the evap system. No codes means the evap monitor (that runs on every key-on engine-on cycle) completed successfully each cycle by monitoring pressure drop in the system. (A leak would have to be smaller than 0.002 inches?(mandated for vehicles starting in 2000) so the evap monitor would pass the evap test.) The "leak" on the fuel tank may be legit, but it would be surprising if it's the root cause of your van's symptoms. Did the tech use a scope and dealer scan tool with a pressure transducer (or an upper-end scan tool) when using the smoke? Maybe a balloon on the canister vent pipe? Were there any pending codes set? Am more inclined to believe there's a? physical issue affecting the evap system or even buggy MAF, ECT, and O2 sensors. Whatever it turns out be be there were no related TSB's by VW re the issue you've described (only anecdotal info from other van owners). Good luck, sir! :-) |
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Thank you Michael.? Had to look up RVP. On Wed, Aug 9, 2023 at 10:29?AM Michael Diehr <md03@...> wrote: An update to the saga - my 2000 EVC is at the mechanic, who just did a smoke test where they pressurize the evap system and gas tank with smoke.? They have found a small leak which appears to be coming from on top of the gas tank, but were unable to determine the precise source of the leak.? |
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On Sat, Jul 22, 2023 at 05:42 PM, Michael Diehr wrote:
The evap system was redesigned for the 2001-2003 years, which don't seem to suffer this issue as much or at allPlease let me share a data point: We have a 2002 EuroVan (Transporter T4 with the 2.8l V6) with about 50k miles on it. ?A few days ago we topped the tank off in Kernville CA at about 100 degrees F, and at the gas station our internal LP gas detector started beeping from all the gas fumes in the van. ?We had never had this problem so I assumed we just spilled some gas at the pump. ?A few hours later, after crawling up to the top of Sherman Pass at 9200 ft, we smelled strong gas fumes and heard boiling gas sounds coming from a little black plastic canister about the size of a coke can, located on the driver side of the van just below and slightly back from the fuel fill location, sitting above a piece of metal shielding, just in front of the propane tank. ?Upon closer inspection, the little black plastic canister had what appeared to be a weep hole on the very bottom outboard edge, a perfect circle about 2mm in diameter. ?Gas would drip out and fall onto the metal shielding immediately underneath it. ?There was intense heat being emitted from what appeared to be a transmission component sitting a few inches ahead of the black plastic canister and also being shielded by the metal, such that one could see the visual manifestation of vapor waves in the air, like at the output of a porch heat lamp. We let it cool off and it eventually stopped boiling. ?I was not sure at a the time if it was a fuel filter, and assumed the presence of a hole was a failure caused by a pebble that I saw had lodged perfectly against the bottom of the plastic canister and the metal shielding underneath it and. had been vibrating away for who knows how long. ?So I put a hose clamp around it to block the spillage, and we carefully drove down the hill a ways; and then the next day, on to Mammoth, where I stumbled across this fantastic group (Hi! by the way) and realised this is probably the evap canister, and that the hole I saw that was conspicuously perfectly circular was more likely a weep hole, than a failure caused by a vibratory errant pebble; and so this morning I have removed my hose clamp. ? I am very concerned by the emission of unburnt liquid fuel from this component and its atomization in close proximity to very a hot engine component (transmission thing?), and the potential for it to combust into flame while driving, unnoticed, with flames being pushed back by the wind onto the propane tank a few inches away. ? |
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Welcome to the group! I'm not familiar with the evap system on the later vans, but others on the list are. Can you take a picture of the part(s)? This email list allows images.
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On Aug 17, 2023, at 5:13 PM, Goffredo via groups.io <phi-lawn-0t@...> wrote: |
Brian C.
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