Author Topic: emissions system question  (Read 1029 times)

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Offline 4380r

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emissions system question
« on: Monday,September 02, 2013, 06:27:45 AM »
So I'm spending this first weekend with the car getting to know it. The compete emissions system was taken off the car. I've notice that sitting in an enclosed garage overnight, there is a scent of gas in the garage. Clears out quickly when the door is opened. No smell when driving.

Checked all the fuel lines, all 'new' with new tees (the plastic ones are long gone)

One thing is that both lines that go from the filler neck to what was the canister are gone. So the little tube at the top of the filler neck that exits out the back is open. Clearly a place for fumes to escape.

Are there implications for simply plugging off those tubes? I guess that essentially creates a sealed system.

Will that impact how/if the car will run properly? Are there safety issues?
Thanks

Offline EuropaTC

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Re: emissions system question
« Reply #1 on: Monday,September 02, 2013, 09:31:34 AM »
I suppose it depends if your gas tank caps have breathing holes in them. If so then you'll be ok plugging the tubes, but if not, and you create a sealed system then I'd guess at some point you'll get a vacuum forming inside the tanks, and presumably fuel starvation ?  It seems an incredible long shot though, knowing good old Lotus I'm betting that even though they had a "sealed emissions system" the filler caps leaked air like no tomorrow....

Brian

Offline buzzer

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Re: emissions system question
« Reply #2 on: Monday,September 02, 2013, 10:00:28 AM »
I would not expect a smell of gas, or petrol as we say over here  :). If left in the garage over night. I would expect fuel and engine oil smells after a run for a while, or if you have a garage with very poor ventilation, but should disappear after a few hours.
I would look further. Sounds like you either have an issue or one developing. 
I think some further investigation may be called for.
Check the fuel tanks for signs of seepage and the carbs. Look for damp looking patch anywhere on the tanks especially around the bottom. the cause would be a small pinhole or pinholes in the tank.
I would also check the base of the carbs for signs of dampness, best to check this about 20 min after a run possible causes would be a weeping or sticky float needle valve in the carb.


Dave
Dave,

Other cars. Westfield SEiW. BMW E90 Alpina D3. BMW 325 E30 convertible and Range Rover CSK

Offline 4380r

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Re: emissions system question
« Reply #3 on: Monday,September 02, 2013, 10:32:55 AM »
Thanks. I've been looking at the service manual, exploded parts diagrams, and researching various sources...

I have checked all the things you suggest, Dave. Tanks are fine, all lines and fittings are new and dry. All plastic connectors replaced with metal. Carbs are dry.

There is discernable smell coming from the car just sitting outside.

My garage is in a condo building, and yes, there is virtually NO ventilation. They basically need to be sealed rooms so that no Carbon monoxide from idling cars escapes into the living units above the garages.

It's been extraordinarly hot here the last few days and evenings, the fuel in the tanks likely expand with the heat, and the expanding vapors likely make their way out of those tubes on the filler neck.

I had a similar issue with an 84 Esprit I owned years ago. Turns out it was the surgical tubing going to the charcoal cannister were deteriorated. $10 worth of tubing and about 10 minutes fixed it, once I realized what it is.

I'm fairly sure it is vapor escaping through the tubes coming out of the filler necks which no longer have lines on them running to the catch cannister, and from their through the charcoal cannister.

To test it I took some small rubber tubing from a hobby air brush and pushed it own through the tube outlet in the filler necks. Fit snug/perfectly through the tube. I then screwed a screw in the end of each of the rubber tubes to plug them.

The car's been baking in the garage for the last few hours, and the odor has diminished considerably.

I think I'm going to get some activated charcoal from the local pet shop, and make two small charcoal filters, run those rubber tubes into them, and tuck them up under the body, out of sight.

I know the tubes in the filler neck are to both control vapors and catch fuel overflow/sloshing when driven hard. At this point, the car likely won't be seeing that kind of hard duty, and I will fill with care (and not top off to allow expansion room) so simply putting together some charcoal filters may take care of the vapor problem.