Home » Public Forums » GMCnet » Need help with STRONG gas Odor
| Need help with STRONG gas Odor [message #94921] |
Sat, 07 August 2010 07:30  |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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After 10 days on the road in Wayne's coach an intermittent and very strong gasoline order has developed.
I have searched for leaks and can find nothing.
On thursday morning I filled up in Cardwell, Montana. About 4200 elevation and headed south toward our next camp at Henry's Lake, Idaho about 6600 ft elevation 15 miles west of West Yellostone, Montana.
A couple of hours later near Earthquale Lake ele. 6400 ft. We started to smell gas. I stopped looked around found nothing.
Don't know temperature but under 90* I think.
The oder went away after we arrived at camp site and coach sat for a few hours.
Yesterday a.m. I bought gas at West Yellowstone, Mt. Didn't fillup and was very careful. No gas spill or burping back from the fill line.
After a couple of hours of slow driving and multiple stops the gas smell came back. Had to open windows and run vent fans just to be able to stay in the coach.
Again the temps are below 90*.
Many severe elevation changes while driving 184 miles in Yellowstone Park. Targhee Pass 7072 ft. twice. going to and returning from the park.
Crossed the contintental divide twice within the park. 8262 ft. and 8391 ft. The highest Dunraven Pass 8859 ft.
The 403 ran fine all the way. No stops, stumbles, or vapor lock.
It starts easily each morning and throughout the day.
This morning -No gas smell yet- But I haven't started the engine yet.
Any suggestions?
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: [GMCnet] Need help with STRONG gas Odor [message #94922 is a reply to message #94921] |
Sat, 07 August 2010 08:38  |
Steven Ferguson
Messages: 3447
Registered: May 2006
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I could be the gasket for the sending unit on top of the tank. Lots
of sloshing with elevation changes and nearly impossible to find
because of the location.
On Sat, Aug 7, 2010 at 5:30 AM, gene barrow <barrowgene@gmail.com> wrote:
>
>
> After 10 days on the road in Wayne's coach an intermittent and very strong gasoline order has developed.
>
> I have searched for leaks and can find nothing.
>
> On thursday morning I filled up in Cardwell, Montana. About 4200 elevation and headed south toward our next camp at Henry's Lake, Idaho about 6600 ft elevation 15 miles west of West Yellostone, Montana.
>
> A couple of hours later near Earthquale Lake ele. 6400 ft. We started to smell gas. I stopped looked around found nothing.
>
> Don't know temperature but under 90* I think.
>
> The oder went away after we arrived at camp site and coach sat for a few hours.
>
> Yesterday a.m. I bought gas at West Yellowstone, Mt. Didn't fillup and was very careful. No gas spill or burping back from the fill line.
>
> After a couple of hours of slow driving and multiple stops the gas smell came back. Had to open windows and run vent fans just to be able to stay in the coach.
>
> Again the temps are below 90*.
>
> Many severe elevation changes while driving 184 miles in Yellowstone Park. Targhee Pass 7072 ft. twice. going to and returning from the park.
>
> Crossed the contintental divide twice within the park. 8262 ft. and 8391 ft. The highest Dunraven Pass 8859 ft.
>
> The 403 ran fine all the way. No stops, stumbles, or vapor lock.
>
> It starts easily each morning and throughout the day.
>
> This morning -No gas smell yet- But I haven't started the engine yet.
>
> Any suggestions?
> --
> Gene Barrow
> Lake Almanor, Ca.
> 1976 Palm Beach
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: Need help with STRONG gas Odor [message #94923 is a reply to message #94921] |
Sat, 07 August 2010 08:47 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| gbarrow wrote on Sat, 07 August 2010 08:30 |
After 10 days on the road in Wayne's coach an intermittent and very strong gasoline order has developed.
I have searched for leaks and can find nothing.
On thursday morning I filled up in Cardwell, Montana. About 4200 elevation and headed south toward our next camp at Henry's Lake, Idaho about 6600 ft elevation 15 miles west of West Yellostone, Montana.
A couple of hours later near Earthquale Lake ele. 6400 ft. We started to smell gas. I stopped looked around found nothing.
Don't know temperature but under 90* I think.
The oder went away after we arrived at camp site and coach sat for a few hours.
Yesterday a.m. I bought gas at West Yellowstone, Mt. Didn't fillup and was very careful. No gas spill or burping back from the fill line.
After a couple of hours of slow driving and multiple stops the gas smell came back. Had to open windows and run vent fans just to be able to stay in the coach.
Again the temps are below 90*.
Many severe elevation changes while driving 184 miles in Yellowstone Park. Targhee Pass 7072 ft. twice. going to and returning from the park.
Crossed the contintental divide twice within the park. 8262 ft. and 8391 ft. The highest Dunraven Pass 8859 ft.
The 403 ran fine all the way. No stops, stumbles, or vapor lock.
It starts easily each morning and throughout the day.
This morning -No gas smell yet- But I haven't started the engine yet.
Any suggestions?
|
Gene,
Please be clear here. You are saying "gas" but from other things I am hoping you mean - Gasoline - Correct??
From your descriptions, it sounds like it might be either leakage on the top of the engine, or the fill vent line that comes from the tanks up to the fill neck (I had a lot of trouble in that area). The fill neck is the only place that there is gasoline inside the coach shell.
I suggest that you lift the engine cover, spin off the air filter and look around. I don't know anything about the 403, so I can be no help past there.
Please be careful with Wayne's coach.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Need help with STRONG gas Odor [message #94926 is a reply to message #94923] |
Sat, 07 August 2010 09:12 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
Karma: 0
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Senior Member |
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What shape are your hoses, are they new??
WHen I had the hoses replaced on Gatsbys' CRUISER, we had a lot of dried and cracked hoses. The large fill hose in the wall panel next to the driver was cracked and leaking and I did get gas fumes in the coach. The rubber was low enough to catch gas slosh and make the smell in if you are going up and down hills, the gas is moving forward and aft.
Whatever the case, if you cannot find a visable reason and your hoses are old and brittle, its time to change the hoses.
Please be very very careful and have extinguishers handy.
Be ready for a fast exit if the worst happens.
You need to be in this mode until the problem is fixed, this is a dangerous situation.
The trip to the Coop Resort that would change the fuel hoses, we had the dogs on leash all the time,ready to stop and abandon the vehicle if there were any smoke at all. Mine was so bad I could not fill the tanks all the way or I would see fuel leaking from under the vehicle..... SOOOoooooo glad to have fixed that....
LarC ( Been there, Done that )
Gatsbys' CRUISER  08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
_
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| Re: [GMCnet] Need help with STRONG gas Odor [message #94927 is a reply to message #94926] |
Sat, 07 August 2010 09:25 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I agree with Larry. Take out the drivers side inner fender and check the
hoses where they attach to the filler neck and really check the vent hose.
The fumes travel up inside the coach via the drivers armrest area. Happened
to me on 78 Royale with 403.
Jim Hupy
Salem, Or
78 Royale 403
On Sat, Aug 7, 2010 at 7:12 AM, Larry <slawrence111@yahoo.com> wrote:
>
>
> What shape are your hoses, are they new??
>
> WHen I had the hoses replaced on Gatsbys' CRUISER, we had a lot of dried
> and cracked hoses. The large fill hose in the wall panel next to the driver
> was cracked and leaking and I did get gas fumes in the coach. The rubber
> was low enough to catch gas slosh and make the smell in if you are going up
> and down hills, the gas is moving forward and aft.
>
> Whatever the case, if you cannot find a visable reason and your hoses are
> old and brittle, its time to change the hoses.
>
> Please be very very careful and have extinguishers handy.
> Be ready for a fast exit if the worst happens.
> You need to be in this mode until the problem is fixed, this is a dangerous
> situation.
>
> The trip to the Coop Resort that would change the fuel hoses, we had the
> dogs on leash all the time,ready to stop and abandon the vehicle if there
> were any smoke at all. Mine was so bad I could not fill the tanks all the
> way or I would see fuel leaking from under the vehicle..... SOOOoooooo
> glad to have fixed that....
>
>
> LarC ( Been there, Done that )
>
>
> --
> Gatsbys' CRUISER :d
> 74 GLACIER X, 260
> 455/APC/4 bagg'r(ver3)
> Remflex Manifold gaskets
> _______________________________________________
> Purchased 08-18-04
>
> _
>
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: Need help with STRONG gas Odor [message #94934 is a reply to message #94921] |
Sat, 07 August 2010 09:56 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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What about the fuel vapor separator in the L rear wheelwell? Or a broken or pinched vac hose to the vapor canister? Not a fix but to eleviate fumes in the coach if you are running the dash air run in NORMAL (fresh) with one of the higher fans settings with the windows closed. This will create positive pressure in the coach and force fumes out instead of draw thenm in.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Need help with STRONG gas Odor [message #94999 is a reply to message #94934] |
Sat, 07 August 2010 23:25 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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I almost named my coach the Valdez for the way it spewed gas on fill up. It stunk of gas 'till we took it to Jim K and had them replace all the soft lines. I complicated issues by having him remove the mechanical pump and install an electric pump. Unfortunately it was too powerful for my carb and caused a rich runing condition with lots of soot, but a pressure regulator seems to have fixed everything. My coach now only has a whiff of gas when we fill up, but nothing after.
Life is very good - we are at a really nice RV Park in Morgan Hill, Ca for the night. Heated pool and jacuzzi, just a very nice, new, park.
On our way to Pismo Beach to chill-out. Trust me, it may be August in the rest of the country, but on the California coast it's November! Brrrrrr!
Larry Davick
The Mystery Machine
(No longer the Valdez, or Deep Water Horizon)
On Aug 7, 2010, at 7:56 AM, John R. Lebetski wrote:
>
>
> What about the fuel vapor separator in the L rear wheelwell? Or a broken or pinched vac hose to the vapor canister? Not a fix but to eleviate fumes in the coach if you are running the dash air run in NORMAL (fresh) with one of the higher fans settings with the windows closed. This will create positive pressure in the coach and force fumes out instead of draw thenm in.
> --
> John Lebetski
> Chicago, IL
> 77 Eleganza II
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: Need help with STRONG gas Odor [message #95248 is a reply to message #94921] |
Tue, 10 August 2010 17:40 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| gbarrow wrote on Sat, 07 August 2010 05:30 |
After 10 days on the road in Wayne's coach an intermittent and very strong gasoline order has developed.
I have searched for leaks and can find nothing.
This morning -No gas smell yet- But I haven't started the engine yet.
Any suggestions?
|
My wife hates gas smell. Two coaches, two gas tank hose jobs and the Onan converted to propane.
As mentioned, be really careful, and look all over the carb and engine for leaks. Check the carbon canister, behind the right front wheel... hard to see against the firewall.
Here is what I think. Gas gets warm and builds pressure in the tanks. Hot day. Warm day, it happens. It is supposed to be relieved by the vapor separator which is by the left front bogie. If the vapor cannot escape to the carbon canistor fast enough, a hose is kinked, the separator is stuck, tank has enough gas to burp up and float the separator ball, it quits venting. If there is a leak in a hose, it vents there and that could be where the hose goes into a steel line that crosses the engine compartment. At about three lbs or so, the gas cap will begin to vent. It is at your left elbow. It sits in a little house that is not sealed very well. Any fumes can come into the chamber at your left and smell yucky. It has happened on both my coaches. Sometimes, after a fill up I did not smell it unless someone, especially a truck, passed on the left. That wiffed the fumes in. I am guessing more coaches have this ailment, but other owners may not have a wife that can spell one part per billion on a windy day with a head cold. (My wife is a sweety; she just can smell gas. She usually says she is loosing brain cells from the odor to motivate me.)
Warning, don't test the theory by suddenly opening the gas cap as you could get a bath.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
[Updated on: Tue, 10 August 2010 17:41] Report message to a moderator |
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| Re: Need help with STRONG gas Odor [message #95279 is a reply to message #95248] |
Tue, 10 August 2010 22:02 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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""Warning, don't test the theory by suddenly opening the gas cap as you could get a bath.
[Updated on: Tue, 10 August 2010 16:41]
--------------------------------------------------------------------------------
'74 Eleganza, SE Best Wishes, George""
I think this is not an unusual condition on GMC's and can happen due a lot of reasons--not all defects. The cap should vent at no higher than 1.5 psi and if it does, it can cause that problem. If the vapor cannister gets loaded it will also cause that. If the carb percolates at idle or after shut down, it will also cause that. Not all of them are dangerous but just what happens. I'm not trying to discount the seriousness of gas smells, but sometimes that is just the way it is.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Need help with STRONG gas Odor [message #95412 is a reply to message #95248] |
Wed, 11 August 2010 21:14 |
gbarrow2
Messages: 765
Registered: February 2004
Location: Lake Almanor, Ca./ Red Bl...
Karma: 3
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Senior Member |
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Thanks to all for the input.
George, I think I married your wife's sister. Very acute sense of smell and irritated by any noxious odor. But this time even I was bothered by the gas smell
I looked every where for leaks including the carb, onan, charcoal canister, and vapor separator. Found nothing.
I finally solved the problem by getting out of the mountains and back to semi level highways at faster speeds.
My theory on the cause is: I filled the tanks in the cool morning both days that we had the problem; leaving little room for expansion.
Then as the day got hotter we climbed higher and higher in elevation decreasing atmospheric pressure.
The combination of these conditions probably caused the vapor to vent out of the fill line and into the overflow behind the side panel next to driver's seat.
We've filled up many times since leaving the mountains and the odor has not returned.
Gene Barrow
Lake Almanor, Ca.
1976 Palm Beach
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| Re: Need help with STRONG gas Odor [message #95427 is a reply to message #95412] |
Wed, 11 August 2010 22:04 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| gbarrow wrote on Wed, 11 August 2010 19:14 |
Thanks to all for the input.
George, I think I married your wife's sister. Very acute sense of smell and irritated by any noxious odor. But this time even I was bothered by the gas smell
The combination of these conditions probably caused the vapor to vent out of the fill line and into the overflow behind the side panel next to driver's seat.
We've filled up many times since leaving the mountains and the odor has not returned.
|
I believe you are right on. This begs the question, why is it not venting. I go back to the separator. It is supposed to not let gas get to the canister, so if yo are too full, it should stop. The tanks are flat, and expand very easily. When testing my tanks, my friend Randy Van Winkle, and I were pretty shocked at the way they blew up like pillow. You can do it with lung pressure, and expand a tank three inches from top to bottom. This works to our advantage. The fuel drops in relation to the top of the tank and this should make room for vapor and let the separator begin to vent. Not always so.
Last weekend we smelled gas, and my system is so tight,there was enough pressure to vent at the cap. I cracked it a bit, and Ruth and I could the tanks "groaning" against the straps.
So, time to check the separator. You can take off the bottom hose, and slip a short piece on and blow. You should easily be able to blow some air to the canister. There is a little resistance. If you make no progress, take off the top hose. Now you should be able to blow freely. If not, rap lightly on it.
New separators are available from corvette suppliers, or Alex Sirum has made a replacement unit.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Need help with STRONG gas Odor [message #95432 is a reply to message #95427] |
Wed, 11 August 2010 22:35 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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Many times the gas station tanks, being buried in the ground, have fuel at a
much cooler temperature than ambient. When we fuel our tanks in the early
part of the day, and fill them quite full, the cool fuel expands enough to
create an overfull condition when it warms up. This probably contributes to
the burping and resulting fumes and odor. If the liquid/vapor separator gets
enough liquid fuel in it, the check ball will close off the vent line to the
charcoal cannister, and this will aggravate the situation.
Jim Hupy
Salem, Or
78 Royale 403
On Wed, Aug 11, 2010 at 8:04 PM, George Beckman <gbeckman@pggp.com> wrote:
>
>
> gbarrow wrote on Wed, 11 August 2010 19:14
> > Thanks to all for the input.
> > George, I think I married your wife's sister. Very acute sense of smell
> and irritated by any noxious odor. But this time even I was bothered by the
> gas smell
> >
> > The combination of these conditions probably caused the vapor to vent out
> of the fill line and into the overflow behind the side panel next to
> driver's seat.
> >
> > We've filled up many times since leaving the mountains and the odor has
> not returned.
>
> I believe you are right on. This begs the question, why is it not venting.
> I go back to the separator. It is supposed to not let gas get to the
> canister, so if yo are too full, it should stop. The tanks are flat, and
> expand very easily. When testing my tanks, my friend Randy Van Winkle, and
> I were pretty shocked at the way they blew up like pillow. You can do it
> with lung pressure, and expand a tank three inches from top to bottom.
> This works to our advantage. The fuel drops in relation to the top of the
> tank and this should make room for vapor and let the separator begin to
> vent. Not always so.
>
> Last weekend we smelled gas, and my system is so tight,there was enough
> pressure to vent at the cap. I cracked it a bit, and Ruth and I could the
> tanks "groaning" against the straps.
>
> So, time to check the separator. You can take off the bottom hose, and
> slip a short piece on and blow. You should easily be able to blow some air
> to the canister. There is a little resistance. If you make no progress,
> take off the top hose. Now you should be able to blow freely. If not, rap
> lightly on it.
>
> New separators are available from corvette suppliers, or Alex Sirum has
> made a replacement unit.
> --
> '74 Eleganza, SE
>
> Best Wishes,
>
> George
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: Need help with STRONG gas Odor [message #95483 is a reply to message #94921] |
Thu, 12 August 2010 10:03 |
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cbwoodsr
Messages: 1063
Registered: February 2004
Karma: 0
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Senior Member |
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Larry...
I also had a pressure regulator between the fuel pump and carb on mine UNTIL...
regulator blew out thru the middle of dial and gave me gas on top of the engine and after the whoosh, a brown streak from the drivers seat to the door...
luckily, only a couple of wires burnt from shorting out from the fire that burnt out quickly...
Put in a steel line from pump to carb..
Only took 3 years to get it back...(Another long story)..
I won't have one anymore...
JWIDNM
Thankx
CBWood
77 Kingslay
MWC OK
ONLINE PARTS PROGRAM
www.GMCMHParts.com
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