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As summer approaches, it's time for the 2024 edition of this topic.
As far as I know, this remains unsolved, though we had some intriguing findings in 2023:
My 2000 EVC has a custom retrofit GM vapor canister, which did help the symptoms quite a bit: I've had no more fumes venting in hot weather at moderate altitudes (up to about 5000 feet). ?However, I still had substantial venting in very extreme conditions (105F+ temperatures, quick drive up to 7500 feet elevation). ? ?Conclusion: a worn out OEM vapor canister may be part of the problem, but is not the only problem.
In summer 2023, both David and I had very similar symptoms in almost the same location: northbound Highway 395, filling up with 91 octane gasoline in one of the little towns (Bishop, Lone pine...). ? His symptoms are worse than mine, which could be since I have a new vapor canister. ? ?
Also, I repeated the same drive in in the southbound direction, but filled up with ethanol-free gasoline, and had absolutely zero problems in similar conditions. ? Conclusion: perhaps the gasoline blend or age matters?
Another clue I found during one of the extreme venting episodes: after releasing all pressure, if I started the engine again, fumes quickly came out again. ?Stop engine: fumes stop immediately. ?The gasoline temperature in the tank was 120F when that was happening.
A few people have pointed to the little metal tab inside the filler neck - the gas cap presses on this when closed to open the breather valve. Bending this a little bit might help? ?I think a few people have said "maybe" but nothing conclusive yet. ?
Anyone have more data?
Mike 2000 EVC
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?I repeated the same drive in in the southbound direction, but filled up with ethanol-free gasoline, and had absolutely zero problems in similar conditions. ? Conclusion: perhaps the gasoline blend or age matters?
?
Southbound is dropping altitude.? I suspect that this is the difference, more than the fuel composition??? Thanks for keeping at this.? I have similar problem that was alleviated years ago by pulling and drying out the cannister.? But it's coming back.?
?
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Hi Steve,?
The route is roughly Bishop CA to Gardnerville NV and back again. The elevation profile looks like this:
Red arrows are where I've had bad venting issues (but only when going northbound).
Note: it's not 16 hours driving, you now have to switch to Biking to get the elevation profile in google maps
1. The elevation gain is steeper heading North vs. South 2. My gas tank was more empty heading southbound
So maybe it's 5 variables? ? heat, rate of altitude gain, absolute altitude, gasoline blend, and % of gas tank filled
Mike
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On Apr 3, 2024, at 6:57 AM, Steve via groups.io <seaweedsteve@...> wrote:
?I repeated the same drive in in the southbound direction, but filled up with ethanol-free gasoline, and had absolutely zero problems in similar conditions. ? Conclusion: perhaps the gasoline blend or age matters?
?
Southbound is dropping altitude.? I suspect that this is the difference, more than the fuel composition??? Thanks for keeping at this.? I have similar problem that was alleviated years ago by pulling and drying out the cannister.? But it's coming back.?
?
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1. The elevation gain is steeper heading North vs. South
2. My gas tank was more empty heading southbound
?
So maybe it's 5 variables? ? heat, rate of altitude gain, absolute altitude, gasoline blend, and % of gas tank filled
Ah.? I was thinking of 395 the way we usually go which is up to Bishop from SoCal on to Mammoth, then back.? And I seem to remember the problem being worst filling in Bishop.? I pulled my cannister in Mammoth, dumped out gas inside, pumped air through it then aired it passively in the dry weather for a week.? It seemed to be solved, though it's returned on occasion years later.? ? I bet you are correct that it's multiple factors.? Difficult problems are often like that.?
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Michael,
I actually followed your same path back as well, starting in Tahoe to Mammoth and then LA, and was going to write up what happened but never did and now I forgot! I do remember that driving around Truckee and the lake there were no problems. And even a trip to Reno and back to Truckee, in pretty intense heat, went OK, but I think by the time we hit Mammoth again it had started back up. Then we lost the A/C and the trip home was a chore because we left Mammoth at 7PM. There was thunderstorms/cooler weather so no more venting problems on that last leg home. I think we'll be headed back in July, so I'll post up.
David 2000 EVC
On Tuesday, April 2, 2024 at 11:28:16 AM PDT, Michael Diehr <md03@...> wrote:
As summer approaches, it's time for the 2024 edition of this topic.
As far as I know, this remains unsolved, though we had some intriguing findings in 2023:
My 2000 EVC has a custom retrofit GM vapor canister, which did help the symptoms quite a bit: I've had no more fumes venting in hot weather at moderate altitudes (up to about 5000 feet). ?However, I still had substantial venting in very extreme conditions (105F+ temperatures, quick drive up to 7500 feet elevation). ? ?Conclusion: a worn out OEM vapor canister may be part of the problem, but is not the only problem.
In summer 2023, both David and I had very similar symptoms in almost the same location: northbound Highway 395, filling up with 91 octane gasoline in one of the little towns (Bishop, Lone pine...). ? His symptoms are worse than mine, which could be since I have a new vapor canister. ? ?
Also, I repeated the same drive in in the southbound direction, but filled up with ethanol-free gasoline, and had absolutely zero problems in similar conditions. ? Conclusion: perhaps the gasoline blend or age matters?
Another clue I found during one of the extreme venting episodes: after releasing all pressure, if I started the engine again, fumes quickly came out again. ?Stop engine: fumes stop immediately. ?The gasoline temperature in the tank was 120F when that was happening.
A few people have pointed to the little metal tab inside the filler neck - the gas cap presses on this when closed to open the breather valve. Bending this a little bit might help? ?I think a few people have said "maybe" but nothing conclusive yet. ?
Anyone have more data?
Mike 2000 EVC
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I finished a 2 month road trip this month, and 6000 miles of filling up, I've found that the high pressure/gurgling seems to happen more with 89+ Octane gas.
I was a diehard 89 midgrade filler-upper for years, and had lots of episodes of boiling/gurgling, high pressure in the gas tank. My house in Boise is at 2700ft, and it's gurgled in the driveway dozens of times (when it's hot).
About a year ago, I went down to 87 octane, and while I don't have firm conviction, I think this has helped this issue. On the road trip we drove through Utah, Colorado, and New Mexico, where they sell a lot of 85 and 86 octane. I swore off 85 octane (I lost two coil packs, and think maybe the spark timing retardation contributed somehow?), but 86 and 87 seemed to be fine at the 4000-8000 ft we were driving. Even in the low, flat lands, 87 was fine.
However, I once put in 89 and once 91 because the delta in price was low and I thought maybe I'd get better MPG that way. Both times, I heard the gurgling after stopping hot until we burned through ~4-6 gallons of gas. I don't think I ever heard it on 86 or 87 octane.
There's a few possible explanations of this (if it's a real effect):
1) regular grade will be fresher, and therefore less volatile? maybe?
2) less ethanol used since it's a lower octane?
3) somehow causes lower heating of the exhaust manifold/piping/catalytic converter, thereby generating less pressure in the overlying gas tank
I haven't done much to my van to address this gurgling, but I am concerned about it. I did pull up on the metal tab under the gas tank (hard enough that I was worried I'd break it), and I replaced the purge valve valve N80 a few times. Neither made any difference, as far as I could tell.
I do wonder how much of the pressure in the tank comes from the heat of the exhaust, and how much from the leak detection pump. I can't say I 100% understand the system as described in the youtube video:
But I'm hoping this discussion will come up with a solution. I was ready to go with Mr. Diehr's GM canister fix, but I'll wait a bit longer for another idea.
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Thanks Andras, great info!
Regarding the Leak Detection Pump (LDP) : I think the LDP only runs occasionally to test the system, and is not likely the source of any significant fuel tank pressurization. ? Several of us have evidence the gasoline in the tank is literally boiling (via the sound, vibrations, or even liquid gasoline spitting out when the gas cap is released). ?It's hard to conceive of how the LDP could cause these symptoms.?
Your theory about gasoline blends is good, and jibes with my experience - I always buy 91 octane, and the worst fume events were after filling up in a small mountain town (Bishop, California) in a hot summer day. ? California has different winter vs. summer blends of gasoline, and the winter has higher vapor pressure. ?Could the 91 Octane gas I'm buying in the summer have a significant quantity of winter blend left over, with higher vapor pressure?
Last summer, I did the same trip northbound and southbound over several mountain passes with 91 Octane gas, with very bad fumes in the northbound direction and none in the southbound direction. ?The main difference: On the southbound trip I was running no-ethanol gasoline.
This summer when I repeat this trip, I should buy lower octane gas as a test.
Mike
p.s. to get a little more data from you:
- is your Eurovan also a 2000 ? - do you have any codes or Check Engine Light? - do you ever have fumes or gurgling on cool days or at lower altitudes? - do you have trouble filling up (the gas pump clicking off before the tank is full?)
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On Jun 25, 2024, at 1:21?PM, Andreas Valentin Decker via groups.io <qvalff8@...> wrote:
I finished a 2 month road trip this month, and 6000 miles of filling up, I've found that the high pressure/gurgling seems to happen more with 89+ Octane gas.
I was a diehard 89 midgrade filler-upper for years, and had lots of episodes of boiling/gurgling, high pressure in the gas tank. My house in Boise is at 2700ft, and it's gurgled in the driveway dozens of times (when it's hot).
About a year ago, I went down to 87 octane, and while I don't have firm conviction, I think this has helped this issue. On the road trip we drove through Utah, Colorado, and New Mexico, where they sell a lot of 85 and 86 octane. I swore off 85 octane (I lost two coil packs, and think maybe the spark timing retardation contributed somehow?), but 86 and 87 seemed to be fine at the 4000-8000 ft we were driving. Even in the low, flat lands, 87 was fine.
However, I once put in 89 and once 91 because the delta in price was low and I thought maybe I'd get better MPG that way. Both times, I heard the gurgling after stopping hot until we burned through ~4-6 gallons of gas. I don't think I ever heard it on 86 or 87 octane.
There's a few possible explanations of this (if it's a real effect):
1) regular grade will be fresher, and therefore less volatile? maybe?
2) less ethanol used since it's a lower octane?
3) somehow causes lower heating of the exhaust manifold/piping/catalytic converter, thereby generating less pressure in the overlying gas tank
I haven't done much to my van to address this gurgling, but I am concerned about it. I did pull up on the metal tab under the gas tank (hard enough that I was worried I'd break it), and I replaced the purge valve valve N80 a few times. Neither made any difference, as far as I could tell.
I do wonder how much of the pressure in the tank comes from the heat of the exhaust, and how much from the leak detection pump. I can't say I 100% understand the system as described in the youtube video:
But I'm hoping this discussion will come up with a solution. I was ready to go with Mr. Diehr's GM canister fix, but I'll wait a bit longer for another idea.
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Mine is a 2000 Weekender
I do occasionally get an Evap code (small leak detected), but not in a while. I've put 4-5 different N80 valves in, but it never helps. I also got an aftermarket gas cap, but nothing has changed
I really only get it after a longish drive on hot days at altitudes of 2000+ ft (I live at 2640 ft). Never fumes, but gurgling that I sometimes vent to keep my gas tank from bursting (bad for smog, but...).?
I have had hard times filling up, but I did a 15 minute drive without my gas cap in and then left the cap off overnight, in an attempt to dry out a maybe soaked charcoal cannister (I propped the gas port flap open with a screwdriver). This didn't cure the gurgling, but it did help the refilling issue. I probably haven't had the refill issue for 2-3 years. Probably unrelated, but I tried the "pull out small metal tab at the top of the fill port" last year. Maybe that also helped the refill issue somehow?
Has anyone reported success from wrapping insulative tape around the exhaust near the gas tank? I feel like that can only help, but it's probably not the cause of our issues, just a bandaid that might lower the probability of gurgling/boiling.?
Have you guys read this thread, especially the last post on page 1 by FranklinH?
The 95 system is probably different from 1997-2000, but I might try pressurizing some of those lines in hope of clearing something out.
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It took me days to read most of the previous posts on this going back years, but I have now done so. I have to say it is a little overwhelming. Here is our experience. ? We recently purchased a 1997 Eurovan Full Camper (91K miles). On its first summer trip, day 1, driving from Phoenix (~1000’ & 104°f) starting with a full tank of regular Costco gas (87 octane) and driving to Payson (~5000’ & 93°f) 90 miles, non-stop 1:30 hours. When stopping for gas and opening the tank, you guessed it, lots of gas vapor. After off-gassing for minutes, the filling it up proved difficult as well, pump clicking off as others have noted. ? Tempted to just run with the gas cap off, but opted instead to just open it up whenever we stopped, or smelled gas. This worked pretty well. I also was careful to orient the gas cap so the two notches were at the 4 and 8 o’clock, (picture included of cap and fill hole). This did not solve the problem, but did mitigate the most obvious symptom, the gas vapor, to a degree. ?   I also noticed when we returned home after a couple weeks of mountain driving the rubber pipe that runs from the N80 to the manifold had a wet look where it goes into the manifold, as well as looking to have melted some of the foam on the backside of the plastic cover (see picture). ?  Next step for us, I think, is to test and replace N80 and also install “…a filter (NAPA Gold 3002) on the line in front of the N80” as someone else did. ? Don’t think this will fix it, as other have noted, this is perhaps a multifactorial problem. But it’s a start, and something reasonably simple to do. Other suggestions or questions are welcome.
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We just got back to our van in preparation for hitting the road this summer.? I'm doing other work on the van (front brake hose was rubbing - worth checking!) and while I have yet to start it up for 8 months, I was getting gas fumes in the heat of the day.? ? This was also happening last summer at the same point in time along with rare occasional fill problems later during travels in the West.
This is the second round as first happened years ago - see previous post.? At that time I don't think I had fumes, just the code and fill trouble.
I don't know if we all have the exact same problem causes or just the same symptoms but I'm having a hard time understanding a mechanism where the slight difference in gasoline formulations could affect static parked fumes escaping.? My best guess is that my cannister charcoal is saturated again, but so hard to believe the cannister held liquid for 8 months in high desert.?
I had already ordered a new Stanton gas cap for it and swapped that out yesterday with no relief.? The vapor is light though.? Have to be nearby the cannister/fill area on the driver side. We actually camp with the van while parked inside a metal garage on our property and it's not noticeable otherwise.?
Location - 5900 ft, Silver City, NM? 90 F
Condition- not started for 8 months, then started later light fumes continued.
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Two more data points:? ?I switched two years ago to regular gas (wish I'd done so years ago) and van runs great with it.? Regular 87.? But symptoms returned (albeit shifted) during new regular gas usage.? ?And ours is a 2002.
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Some additional information.
?
Prior to purchasing our EVC (December, 2023, The cold month in Arizona) it had a check engine light on with an error code of P0411 (Sec.Air Inj.Sys. Incorrect Flow Detected (/g/eurovanupdate/topic/check_engine_light_error_code/45650733)). The previous owner had the mechanic clear the code and started using regular gas which the mechanic thought might help prevent the return of the P0411 code. I do not think the P0411 is part of the gas fume problem we are talking about here.
?
To date neither the check engine light nor presumably the code has returned. Our EVC passed Phoenix emission testing, shortly after we bought it. Neither our mechanic
nor the MVD has said we have any codes present. We have run only regular gas.
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Check your fuel pump tank cover, the metal gas tubes molded into the cover can rust causing the plastic to crack. This was the source of my faint gas smell issues.
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I suggest checking the fuel tank cover, the part removed when accessing the fuel pump. This part has gas line fittings molded in place, the metal tubes can rust causing the plastic to crack. When I was replacing my fuel pump I found this issue on my 2003. This is fairly easy to check from inside the van through the port in the floor, which is located between the driver seat and passenger seat, under the carpet. I removed the driver seat and hand brake, cut carpet along the passenger base and pulled it up from behind the seat toward the front. You could just remove both seats and minimize carpet cutting. I did have a faint gas smell at times before replacing the part but non after. Good luck, Bill.
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For my next trip, the forecast is very hot, so I'll keep all other variables the same (same destination, fill up in the same locations with 91 octane, etc.)
Since last year, my van has had the following repairs which may affect the evap system: - new timing chains (and sprockets, guide rails, tensioners...) - two new oxygen sensors
One theory is that a rich-running condition (real or mistaken) could cause the ECM to not open the N80 purge valve enough, leading to a build-up of vapors. ?With new timing chains and oxygen sensors, it's possible that's fixed?
Also, I figured out how to use VCDS to monitor the N80 valve duty cycle: 1. Open Engine controller (01) 2. Go to Measuring Blocks (08) 3. Select Group 150 ?(Note: on other vehicles, it may be Group 70 ? See??) This will show the N80 valve duty cycle (from 0% to 100%). ?
Here's an example of driving around town. ?The evap % duty cycle (light blue line) seems to work as follows: - stays at 0% when first starting, until the engine is warm - heads towards 100% when accelerating or at steady throttle - drops back to 0% immediately when you decelerate? - at idle, may slowly creep up towards 30%-50%
I conclude from this that my N80 evap system appears to be working normally (at sea level in 75F temperatures at least)
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Just back from a "hot & high" trip, which was a repeat of last year's trip: Exact same route, bought gas on the same stops, weather was about the same. The trip finishes with a quick rise up to about 7500' altitude. This is in a 2000 EVC.
But unlike last year, there were no fumes at the end when I stopped at all. Zero.
I was using VCDS to watch the N80 function and it seemed sensible to me: running at 100% (fully open) when accelerating or going at steady cruise.
I had zero trouble filling up, and the van seemed to run great the whole way.
So, what's different between this trip and last trip?
- my van had significant engine work done, including timing chains and new oxygen sensors.
- it was smoke tested and the mechanic noted "breather on top of tank had small amount of smoke escaping, removed clamp and re-secured with new clamp"
There were, however, some symptoms:
1. slight fumes during some really hot sections (105F) at medium altitude (3000'-4000') but they were subtle and hard to locate: not coming from engine compartment, tailpipe, or gas cap. Probably coming from around the gas tank? This is not a new symptom.
2. after returning home and the van sitting over night, I feel like there's a distinct smell of gasoline in the oil. This may or may not be a new symptom as I wasn't in the habit of sniffing my oil in the past.
Any ideas?
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On Wed, Jul 17, 2024 at 01:09 PM, Michael Diehr wrote:
the N80 function and it seemed sensible to me: running at 100% (fully open)
FYI, the N80 has 2 possible states - closed or cycling.? It's never (intentionally) left energized.
--
Duane
05HD Rialta
227K Miles
?
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On Jul 17, 2024, at 11:21?AM, Duane <txpigeon@...> wrote:
On Wed, Jul 17, 2024 at 01:09 PM, Michael Diehr wrote:
the N80 function and it seemed sensible to me: running at 100% (fully open)
FYI, the N80 has 2 possible states - closed or cycling.? It's never (intentionally) left energized.
Right - I believe it uses Pulse Width Modulation (PWM) and cycles from 0% (fully closed) to about 100% (fully open).? PWM typically uses a square wave, so 100% PWM would be the same as +12V DC.? When I was graphing it using VCDS, it clearly went over 99% a few times.
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Did you run regular or premium gas? Last year, I think you ran premium? If it helps, I'm open to using regular per the recent posts here, it's just ironic that 12 years ago the mantra was always premium. Consequently, I've never put a drop of anything else in it. We'll be doing the same trip in a couple weeks again as well.
Thanks, David 2000EVC
On Wednesday, July 17, 2024 at 11:09:58 AM PDT, Michael Diehr <md03@...> wrote:
Just back from a "hot & high" trip, which was a repeat of last year's trip:? Exact same route, bought gas on the same stops, weather was about the same.? The trip finishes with a quick rise up to about 7500' altitude.? This is in a 2000 EVC.
But unlike last year, there were no fumes at the end when I stopped at all.? Zero.
I was using VCDS to watch the N80 function and it seemed sensible to me: running at 100% (fully open) when accelerating or going at steady cruise.?
I had zero trouble filling up, and the van seemed to run great the whole way.
So, what's different between this trip and last trip?
- my van had significant engine work done, including timing chains and new oxygen sensors.
- it was smoke tested and the mechanic noted "breather on top of tank had small amount of smoke escaping, removed clamp and re-secured with new clamp"
There were, however, some symptoms:
1. slight fumes during some really hot sections (105F) at medium altitude (3000'-4000') but they were subtle and hard to locate: not coming from engine compartment, tailpipe, or gas cap.? Probably coming from around the gas tank?? This is not a new symptom.
2. after returning home and the van sitting over night, I feel like there's a distinct smell of gasoline in the oil.? This may or may not be a new symptom as I wasn't in the habit of sniffing my oil in the past.
Any ideas?
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Does anyone know of a Euro van mechanic in Colorado Springs? Thank you
Did you run regular or premium gas? Last year, I think you ran premium? If it helps, I'm open to using regular per the recent posts here, it's just ironic that 12 years ago the mantra was always premium. Consequently, I've never put a drop of anything else in it. We'll be doing the same trip in a couple weeks again as well.
Thanks, David 2000EVC
On Wednesday, July 17, 2024 at 11:09:58 AM PDT, Michael Diehr < md03@...> wrote:
Just back from a "hot & high" trip, which was a repeat of last year's trip:? Exact same route, bought gas on the same stops, weather was about the same.? The trip finishes with a quick rise up to about 7500' altitude.? This is in a 2000 EVC.
But unlike last year, there were no fumes at the end when I stopped at all.? Zero.
I was using VCDS to watch the N80 function and it seemed sensible to me: running at 100% (fully open) when accelerating or going at steady cruise.?
I had zero trouble filling up, and the van seemed to run great the whole way.
So, what's different between this trip and last trip?
- my van had significant engine work done, including timing chains and new oxygen sensors.
- it was smoke tested and the mechanic noted "breather on top of tank had small amount of smoke escaping, removed clamp and re-secured with new clamp"
There were, however, some symptoms:
1. slight fumes during some really hot sections (105F) at medium altitude (3000'-4000') but they were subtle and hard to locate: not coming from engine compartment, tailpipe, or gas cap.? Probably coming from around the gas tank?? This is not a new symptom.
2. after returning home and the van sitting over night, I feel like there's a distinct smell of gasoline in the oil.? This may or may not be a new symptom as I wasn't in the habit of sniffing my oil in the past.
Any ideas?
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Bill Wiggins
Duane