| [GMCnet] Fuel canister question [message #87125] |
Thu, 03 June 2010 14:10  |
KB
Messages: 1262
Registered: September 2009
Karma: 0
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I'm replacing all the fuel lines on the beast, and have a question about
how the double canisters in front are supposed to be routed. I've looked in
the manual, but my installation has huge loop-de-loops of hose not shown in the manual.
Also found another vacuum leak here in a worn section of hose...
Anyway, is there a reason to have big loops of hose to/from the canisters? Is
this to act as a trap or something, or is our installation (possibly by a PO) just weird?
There are also for unknown reasons, a couple of pieces of steel tube in the loops,
about 6 inches long. Any reason?? They don't seem to be related to heat exposure
as they're pretty randomly placed, and I don't see them in the manual diagram.
I searched the photo site, but couldn't find pictures of other folk's canister installation.
Hints appreciated.
thanks,
Karen
1973 23' Patience Tester
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Karen
1975 26'
San Jose, CA
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| Re: [GMCnet] Fuel canister question [message #87174 is a reply to message #87125] |
Thu, 03 June 2010 19:42  |
Gail Marks Cruiser
Messages: 125
Registered: August 2009
Location: Gold Coast, Australia
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G'day,
From what I can remember the twin cannister is a later model (Californian) emissions requirement.
In the '77&'78 supplement manual (X7725) in section 6T page 6 there is a good diagram of the '78 emissions system. A P.O. had coloured in the different systems to make it easier to understand.
When I replaced all my fuel lines I decided to attack the canisters too. I also found they didn't seem right , like it had had a quick patch job, and it also had some steel tubing in places.
I decided to pull it all out, and look at it on the bench, to see if it made more sense.
The lower cannister was rusted in place and I ended up breaking it to get to the bolts to remove it.
On the bench it looked like the second canister was supposed to double up on the function of the first one.
Instead of replacing the broken cannister I decided to just go the earlier model, single cannister route, which made more sense and looked easier to do. Except they are a different size in the circumference, didn't fit the lower holder.....easily.
We have no smog checks here, but if you do, it is probably best to keep the original set-up.
I'm still thinking about axing the cannister all together- pro's and con's.
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
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| Re: [GMCnet] Fuel canister question [message #87194 is a reply to message #87125] |
Thu, 03 June 2010 21:13 |
KB
Messages: 1262
Registered: September 2009
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Thanks Mark. I think I'll do what you did and take the canisters out for inspection.
I asked a mechanic friend, and he said it sounded like ours was set up
by a marine mechanic -- the big loops were to prevent fuel running up the vent
lines if the tanks are full (on boats). I don't know if we need anything quite
so exuberant to achieve that since it'd have to run through the vapor separator first.
I'm not sure if the lines I'm looking at are original though they're pretty old.
Still no clue what the short steel splices were about. I think even early coaches were subject
to California emissions -- the '73 manual shows the double canisters.
I've read that if you take the canisters out, you'll smell gasoline in the cockpit.
Don't know if that's true, but you'd still need some kind of vent.
I have a an early coach specifically because I didn't want to deal with California's smog checks.
thanks,
Karen
1973 23' Patience Tester
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Karen
1975 26'
San Jose, CA
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| Re: [GMCnet] Fuel canister question [message #87221 is a reply to message #87125] |
Thu, 03 June 2010 22:18 |
Gail Marks Cruiser
Messages: 125
Registered: August 2009
Location: Gold Coast, Australia
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Emery thank you, Just what I wanted to hear. My canister does leak if I fill the tanks on a hot day, and leave it sit.
I now only fill it when I am heading off, don't like the idea of fuel dribbling between a hot engine and even hotter exhaust.
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
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| Re: [GMCnet] Fuel canister question [message #87232 is a reply to message #87203] |
Thu, 03 June 2010 22:59 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| emerystora wrote on Thu, 03 June 2010 19:35 |
>
>
You won't smell any gas in the cockpit if you take out the line and
run a short line from the liquid / vapor seperator down to the bogie
in the rear wheel well.
If you don't have to worry about CA smog tests just eliminate the
cannisters. Most of them leak anyway sov ou won't be releasing any
more vapors than if you leave them on. Besides your engine will run
better
Emery Stora
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I would respectfully disagree with the removal of the canisters. If they leak, it is not the canisters, unless they are cracked. It is the separator valve, in my opinion. If it does its job, no gas will reach the canisters. Venting it by the wheel well... hmm, my wife's head is near that wheel well when we sleep.
We can gripe about the EPA all we want, but as a person who lived in the LA basin during my childhood, I disagree. We moved to the Central Valley when you could come over the grapevine and see practically to Sacramento, 300 miles away. Now, 35 years later, we can hardly see the valley floor. It is not the factories, because we have very few. It is not cows although some have tried to pin it on the cows who were here 30 years ago. It is cars. Period.
On my gas pumps there is a little note about gas being a carcinogen. The canister keeps hydrocarbons out of the air and the best part is that not only does it capture them, you get to use them to drive down the road, later. You get to use what would have boiled off to make the coach run. This is a win win. End of boring speech.
Besides, my wife hates the smell of gas, so I had to make sure all was tight in the system... on two coaches.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] Fuel canister question [message #87331 is a reply to message #87221] |
Fri, 04 June 2010 21:54 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Mark
That sounds like a classic case of the fuel separator float valve leaking. If the tanks are near full it will cause gas to leak out of the canisters. This can be bad as the exhaust is close by. The separator is located in the driver side wheel well.
Roy
Roy Keen
Minden,NV
76 X Glenbrook
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