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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50336
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Posted: Thu Aug 03, 2017 10:58 am Post subject: Oregon gasoline and hot weather |
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Yesterday my wife picked me up at the Portland airport in the 100°F+ heat of the afternoon. She had gotten stuck in traffic on Airport Way where it intersects with I-205, taking 40 minutes or so to go a mile or two. When she picked me up I commented that the car smelled of gas. On leaving the airport and entering the stalled traffic again the idle became erratic and the engine began to stall, it was hard to restart and had to be revved to be kept running.
What was happening is that without airflow under the rig the gas in the tank had gotten hot enough to boil, but once we got out on the open road the tank cooled and the problem resolved itself. The Oregon summer gas blend is just not suitable for the most extreme heat that a PNW summer can deliver. I and many others have had problems with carbureted rigs on hot days, but this is the first time I have had problems with a FI rig on a roadway. I have had similar problems before with my Toyota truck when using it for a prolong time as a tractor in extreme heat.
If you think that you may be experiencing this problem, do not remove the fuel cap, as with the pressure in the tank reduced the fuel may boil violently spewing gas out the fill. |
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danfromsyr Samba Member
Joined: March 01, 2004 Posts: 15143 Location: Syracuse, NY
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Posted: Thu Aug 03, 2017 11:10 am Post subject: Re: Oregon gasoline and hot weather |
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had an isuzu trooper once where the bad repair of exhuast flexpipe fell off and pointed directly at the steel fuel tank.
was wondering what sounded like a tea kettle whistle at a stop light.
drove on.
next stop light same tea kettle.
got out and discovered it was my gas cap.
opened the gas cap (foolish in hindsight) and WHOOOOOOOssssshhh
no fuel but a hot air blast from the compressed air/expansion..
we took a walk and let it cool down there on the side of the road..
later repointed the flex pipe and took it home to repair. _________________
Abscate wrote: |
These are the reasons we have words like “wanker” |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6529 Location: Westfalia, Earth
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Posted: Thu Aug 03, 2017 11:46 am Post subject: Re: Oregon gasoline and hot weather |
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Wow. Can't wrap my head around this one, how could it get to its boiling point of approximately 180 degrees?
The running condition sounds identical to the few times we've vapor-locked. Not discounting you one bit Bud, just baffled how the temp could get to a point of boiling.
I'd be inclined to think if not vapor lock, then perhaps it was over-pressurized and isn't venting properly. _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50336
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Posted: Thu Aug 03, 2017 11:56 am Post subject: Re: Oregon gasoline and hot weather |
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E1 wrote: |
Wow. Can't wrap my head around this one, how could it get to its boiling point of approximately 180 degrees?
The running condition sounds identical to the few times we've vapor-locked. Not discounting you one bit Bud, just baffled how the temp could get to a point of boiling.
I'd be inclined to think if not vapor lock, then perhaps it was over-pressurized and isn't venting properly. |
The engine and fuel pump continually add heat to the fuel, but the heat is dispersed via air flow under the rig. No or little air flow on a hot day can cause the fuel to reach the boiling point especially if the fuel is not formulated to handle high temps. |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6529 Location: Westfalia, Earth
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Posted: Thu Aug 03, 2017 12:24 pm Post subject: Re: Oregon gasoline and hot weather |
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Thank You, that does make sense now. _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10367 Location: Sunshine Coast B.C.
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Posted: Thu Aug 03, 2017 12:50 pm Post subject: Re: Oregon gasoline and hot weather |
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I had a very noisy fuel pump then stall at idle and no start in the middle of nowhere OR. This was at higher altitude. Removed fuel cap, "whoosh". Van restarted no problem. I'd assumed a vacuum had been created but in hindsight, I bet I was wrong.
Shouldn't the Vanagon EVAP system vent off pressure? Or, is the rate of expansion too much for a properly functioning EVAP system to handle?
Thanks for the warning Wildthings.
Neil. _________________ 1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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djkeev Samba Moderator
Joined: September 30, 2007 Posts: 32574 Location: Reading Pennsylvania
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E1 Samba Member
Joined: January 21, 2013 Posts: 6529 Location: Westfalia, Earth
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Posted: Thu Aug 03, 2017 2:04 pm Post subject: Re: Oregon gasoline and hot weather |
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Vanagon Nut wrote: |
Shouldn't the Vanagon EVAP system vent off pressure? Or, is the rate of expansion too much for a properly functioning EVAP system to handle?
Thanks for the warning Wildthings.
Neil. |
This is precisely what I think.
Does anyone know if the charcoal canisters can be rebuilt? _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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Tom Powell Samba Member
Joined: December 01, 2005 Posts: 4855 Location: Kaneohe
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Posted: Thu Aug 03, 2017 2:46 pm Post subject: Re: Oregon gasoline and hot weather |
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From the internet:
"Gas doesn't typically "boil", but it does vaporize (evaporate) at anything over 93 degrees F or so. As I understand it, the "boiling point" of regular 87 unleaded is about 181 degrees...but this will differ depending on pressure and what additives are in the gas."
Aloha
tp |
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DuaneL Samba Member
Joined: February 02, 2012 Posts: 511 Location: Spokane WA
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Posted: Thu Aug 03, 2017 3:27 pm Post subject: Re: Oregon gasoline and hot weather |
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also from the internet
Not being a pure substance, gasoline has no single boiling point. Instead, the lighter fractions start boiling out at 90-100 degrees F, with more and more evaporated as the liquid temperature increases, until the final, heaviest fractions evaporate in the 300-400 degrees F range. This behavior is called the “distillation curve.” Ethanol boils at 178.5 degrees F, while water boils at 212 degrees F. _________________ ____________
1971 std bug, 1776, ACN Super Stock 34-3, dvda dist, 27x8.50 14 tires |
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photogdave Samba Member
Joined: April 05, 2004 Posts: 3048 Location: Vancouver Island, B.C.
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Posted: Thu Aug 03, 2017 5:46 pm Post subject: Re: Oregon gasoline and hot weather |
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Vanagon Nut wrote: |
Shouldn't the Vanagon EVAP system vent off pressure? Or, is the rate of expansion too much for a properly functioning EVAP system to handle?
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I'm not sure about the 2WD system but I've had this happen a couple of times in my Syncro. Off-roading in high temps in both Oregon and Baja, pressure built in the tank and forced gas into the charcoal canister. When I removed the fuel cap in one case, gas came shooting out. Like Dave said, bypassing the canister solves the problem.
I ran for about a year without one but found a good used one at Westy Werkes so giving the evap system another chance. _________________ 89 Syncro GL Westfalia 2.1 WBX/WBXaustSS
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Stop dead photo links! Post your photos to The Samba Gallery! |
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lostinavan Samba Member
Joined: November 10, 2016 Posts: 31 Location: Southern Oregon
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Posted: Thu Aug 03, 2017 5:46 pm Post subject: Re: Oregon gasoline and hot weather |
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Bro, you should always take 82nd to pdx during high traffic |
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Merian Samba Member
Joined: January 04, 2014 Posts: 5212 Location: Orygun
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Posted: Thu Aug 03, 2017 6:15 pm Post subject: Re: Oregon gasoline and hot weather |
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the charcoal in the canisters will last nearly forever unless you get liquid gas inside there
more likely is that one will burst open 2-3 times per century, spilling the still good granules out _________________ .... |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6529 Location: Westfalia, Earth
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Posted: Thu Aug 03, 2017 9:20 pm Post subject: Re: Oregon gasoline and hot weather |
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How does liquid gas get into the canisters? _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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Team WorldTour Samba Member
Joined: September 02, 2010 Posts: 2426 Location: Der Vaterland
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Posted: Thu Aug 03, 2017 9:49 pm Post subject: Re: Oregon gasoline and hot weather |
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E1 wrote: |
How does liquid gas get into the canisters? |
I'm guessing as a vapor. Cools, condenses, et viola, fuel in canister. _________________ 1990 Feldjäger Syncro AAZ
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When All Else Fails: Lather, Rinse, Repeat! |
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drj434343 Samba Member
Joined: January 31, 2016 Posts: 398 Location: Portland, OR
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Posted: Fri Aug 04, 2017 8:53 am Post subject: Re: Oregon gasoline and hot weather |
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Hot or boiling gas in the tank and vapor lock may not be mutually exclusive either. The hotter the incoming gas from the tank, the less delta-T remains for the heat soak in the engine compartment. |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22639 Location: NYC/Upstate/ROW
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Posted: Fri Aug 04, 2017 10:22 am Post subject: Re: Oregon gasoline and hot weather |
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E1 wrote: |
Wow. Can't wrap my head around this one, how could it get to its boiling point of approximately 180 degrees?
The running condition sounds identical to the few times we've vapor-locked. Not discounting you one bit Bud, just baffled how the temp could get to a point of boiling.
I'd be inclined to think if not vapor lock, then perhaps it was over-pressurized and isn't venting properly. |
The boiling point is where the "vapor pressure " (loosely speaking as gasoline isn't a chemical compound) equals the ambient atmospheric pressure. Long before you reach the 180ish range, the pressure on the tank is climbing and whistling and popping hoses , etc. Th pressure climbs linearly with temperature to a good appproximation, based on absolute zero, not 0F. _________________ .ssS! |
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dgbeatty Samba Member
Joined: October 26, 2006 Posts: 702 Location: Sacramento
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Posted: Fri Aug 04, 2017 10:23 am Post subject: Re: Oregon gasoline and hot weather |
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We had this problem recently on Mount Diablo here in California. We have wonder gasoline here and it does strange things.
The A/C was running at max with road speed of a bit over 10mph, 100f or a bit higher the road grade was ~~10%.
The only real solution is a fuel cooler such as used by MB since the eighties. The fuel return line is cooled by the low presure A/C line right before it enters the compressor.
I would judge the fuel pump temp to been over 150f, maybe as high as 180f. It was much to hot to touch. I would compare it to a dark colored car hood parked in the sun which often measure over 180f.
I let it set for 45 minutes with a fan blowing on it. Afterwards it was fine.
It was assumed that vapor lock would a thing of the past with electric fuel pumps mounted below or inside the fuel tank along with recurculaing higher fuel pressure systems. The modern gasoline blends have proven that not to be true. In response car companies have steadily increased the fuel pressure, added fuel cooling, and valves that block all flow, due to heat soak, when the engine is switched off. We may need to do some of the same! |
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Vanagon Nut Samba Member
Joined: February 08, 2008 Posts: 10367 Location: Sunshine Coast B.C.
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Posted: Fri Aug 04, 2017 11:10 am Post subject: Re: Oregon gasoline and hot weather |
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Vanagon Nut wrote: |
I had a very noisy fuel pump then stall at idle and no start in the middle of nowhere OR. This was at higher altitude. Removed fuel cap, "whoosh".
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During that trip, I'd suspected my charcoal filter was part of the issue. I recall picking up a used filter for a Mk3 Jetta. There is a thread or two on charcoal filters here but that Jetta part seemed very similar or the same as the Vanagon part. As it turned out, the filter that was already mounted passed air so I didn't see that as the issue. Some have opened up their filters to clean them. I recall a thread about someone swapping out the OEM charcoal for fish tank pump charcoal. I wouldn't do either of those things though. I do see links to new filters online.
I know this subject has been discussed here but I'd think that routing engine fuel hoses higher [edit: up off the engine] would help keep fuel cooler. How much cooler, who knows? I did this on my '88 similar to how the tencentlife engine is done.
Neil. _________________ 1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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dgbeatty Samba Member
Joined: October 26, 2006 Posts: 702 Location: Sacramento
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Posted: Fri Aug 04, 2017 11:02 pm Post subject: Re: Oregon gasoline and hot weather |
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Vanagon fuel tanks are only good for a few "whooses" when removing the fuel cap. The temp fix is to remove the cannister and whack the ground with it a few times to shack up and loosen the charcoal. Or disconnect the large line on the top. After the maximum number whooses has been exceeded call your favor vendor and order a replacement for your now collapsed fuel tank. |
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