Emission control hose routing for Fiat 850 Sport Spider

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Emission control hose routing for Fiat 850 Sport Spider

Postby Bob » Sun Jan 10, 2010 6:04 pm

I've been trying to work out the routing of the hoses on my '72 Fiat 850 Sport Spider. These were "reworked" when I got the car and I cannot find sufficient documentation on how all the hoses were routed originally. Here are some photos - anyone know the correct routing?

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On the firewall above the carburetor is a hose that's been plugged off with a bolt. No idea where that goes. On the bottom of the air-cleaner housing, there are two nipples. One, about a half-inch in diameter leads to the valve cover on the side of the filler tube. The other nipple is about 1/4" O.D. and has also been blocked off. No idea where that one goes.

The other photos show the electroswitch and carbon canister. There are two hoses of the same size going into the intake manifold. One of those nipples is full size, where the other is closed off with a pinhole opening. I believe this is intentional, but I'm not sure if I have the right hose going to the right hole.

Another unrelated question: there's a electrical item that looks like a condenser attached to the bracket that holds the coil. As you can see from that photo, this device has been disconnected. What is it? Where should the lead be attached? What does it do? What's the effect of it not being connected (never seemed to impact it running OK).
Last edited by Bob on Wed Aug 20, 2014 1:26 pm, edited 1 time in total.
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Postby Dwight V. » Sun Jan 10, 2010 7:48 pm

The parts book *may* show where some of those lines go. Unfortunately, I no longer have mine and Shaun Folkerts has all my fiche.

One thing I can advise is get rid of that plastic fuel filter! Those are extremely dangerous in an 850 and have been known to melt. You can guess the results. Metal or metal/glass only.
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Postby Bob » Thu Jan 14, 2010 9:19 pm

Good call on the filter. I only bought that because I was trying to diagnose what ended up being a blown head gasket in the first place. I'm going to revert to the all-metal filter as soon as I get time this weekend. In the meantime, the car isn't going anywhere.

So, does anyone have a Parts Manual for the 1972 Sport Spider 850 that could look up the routing of the hoses?

Also, anyone know where the lead on the little electrical component next to the coil goes? I can re-wire it, but I'd like to know where it goes first.

-Bob
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Postby bill vail » Fri Jan 15, 2010 10:25 am

I'll scan it tonight and e-mail it. Bill
1972 Fiat 850 spider
1976 Checker
2000 Kia Sportage
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Postby Muck » Fri Jan 15, 2010 4:19 pm

I was gonna try to take some photos of my hose routing. I'll look forward to the "official" routing.
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Postby bill vail » Fri Jan 15, 2010 5:34 pm

The condensor I don't have as I have converted to an electronic ignition which doesn't require. I'm currently looking for all my parts manuals. As soon as I locate, hopefully within the hour I'll scan the piping layout.
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Postby Bob » Fri Jan 15, 2010 8:01 pm

Super! Thanks Bill.
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emissions control systems

Postby Bob » Sun Jan 17, 2010 7:00 pm

OK, here's what I found. Remember, this is for the later model Fiat 850 Sport Spider and I suppose the Sport Coupe too (mine is a 1972 spider). I don't know yet how early they started using all this plumbing, but from what I've seen it applies to 1971-73 at least.

There are two separate emissions control systems. One is the Evaporative emissions control system which deals with regulations intended to stop gasoline evaporation from getting to the atmosphere. This means that our gastanks and related piping are a closed system. The owner's manual has a brief but informative description of how all this works that I won't go into. I'll just recite which hose goes where. The principle device in this setup is the charcoal canister that is attached to the right side of the engine compartment. There are three hoses coming out of this gizmo - One on top and two out the bottom.

The second is the Exhaust emissions control system which is intended to minimize the amount of unburnt hydrocarbons from getting into the atmosphere. There are a number of hoses and devices attached to this system - some separate from the others, but I guess the intention was for them all to work together.
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Postby Bob » Sun Jan 17, 2010 7:08 pm

OK, first the Evaporative emission control system. Here's the page out of the owner's manual that shows the various components.
Image

Don't get fooled by the diagram - all the parts are in different relative positions than you'd see under the hood, but the logical routing is correct. Here's a photo of the carbon filter on my car.
Image
and another from the bottom looking up.
Image
Note there is one hose on top that goes to the vacuum fitting on the passenger side of the intake manifold. There are two fittings on the bottom. The center one goes to the plastic 3-way valve above the coil and radiator. The larger one on the bottom goes to the exhaust manifold fitting where it picks up hot air to activate the carbon in the canister and release the gas vapor.
Last edited by Bob on Sun Aug 24, 2014 4:05 pm, edited 1 time in total.
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Postby Bob » Sun Jan 17, 2010 7:28 pm

Now for the exhaust emission control system. Here's the diagram out of my Haynes manual that shows the various components in schematic, a drawing of the clutch pedal switch, and a photo of the electrovalve.
Image

Key here is the fast idle vacuum device which is mounted on the driver (left) side of the carburetor. This device when prompted by the flow of vacuum, opens the throttle to around 1600 rpm. This is controlled by a number of electrical switches that when activated, open the electrovalve causing vacuum at the Fast Idle Device to open the throttle. This can be caused to activate during driving (under certain conditions), and by use of the manual switch on the left side of the engine compartment (useful for emission testing if you have to). Here's a photo of the Fast Idle Vacuum Device on my car. It's the mechanism with the braided hose coming into it from the left.
Image

The braided hose runs across the firewall from the electrovalve to the Fast Idle device above the radiator.
Image
Last edited by Bob on Sun Aug 24, 2014 4:08 pm, edited 1 time in total.
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Postby Bob » Sun Jan 17, 2010 7:33 pm

Further, there are two hose fittings on the bottom of the air filter housing. One, about a half-inch in diameter runs directly to the oil filler tube and contains a spring-shaped filter that fits snugly inside. A smaller fitting goes directly to the plunger valve on the intake manifold right below the carburetor. You can see both hoses here just to the right of the Fast Idle Vacuum Device. The throttle linkage goes between them to the carburetor.
Image
Last edited by Bob on Sun Aug 24, 2014 4:12 pm, edited 1 time in total.
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Postby Bob » Sun Jan 17, 2010 7:41 pm

Lastly, here is a photo of the intake manifold showing the three hoses that go into it's fittings. The intake manifold is directly below the black gasoline catch pan between the carburetor and the manifold. The plunger valve is in the manifold (a little piston and spring) and is actuated by the linkage on the carburetor. On the left is the hose from the electrovalve. In the center is the plunger valve which takes the hose from the small fitting on the bottom of the air filter housing. The one on the right side of the manifold comes from the top of the carbon filter. This opening had been plugged by a previous owner of my car. I had to manufacture a replacement nipple to accomodate the hose.
Image
Last edited by Bob on Sun Aug 24, 2014 4:13 pm, edited 1 time in total.
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Postby Bob » Sun Jan 17, 2010 7:43 pm

Bill, I want to thank you again so much for providing me with the information you graciously sent - it was invaluable in solving this riddle! I owe you!

Regards,

-Bob
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Re: Emission control hose routing for Fiat 850 Sport Spider

Postby snekdak » Wed Sep 28, 2016 12:19 pm

Apologies in advance for to reviving this old post.

I have a '70 850 spider and want to replace my exhaust system with a period correct mufflerless "racing" one. Currently, there is a vacuum hose going from the header to the carb and a braided cloth hose going to the emissions canister (both coming out of the same connection in the exhaust header). The replacement exhaust I have does not have that connector on it at all.

Is this a necessary part for the car to run well? I understand my emissions will be higher and I am going to leave the canister in place for easy swap between original and the mufflerless exhaust. If this is needed for the car to run well, what would that part be called so I can find one and have it welded in?
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Re: Emission control hose routing for Fiat 850 Sport Spider

Postby StanfordK » Sun May 07, 2017 11:38 pm

snekdak wrote:Apologies in advance for to reviving this old post.

I have a '70 850 spider and want to replace my exhaust system with a period correct mufflerless "racing" one. Currently, there is a vacuum hose going from the header to the carb and a braided cloth hose going to the Bathmate emissions canister (both coming out of the same connection in the exhaust header). The replacement exhaust I have does not have that connector on it at all.

Is this a necessary part for the car to run well? I understand my emissions will be higher and I am going to leave the canister in place for easy swap between original and the mufflerless exhaust. If this is needed for the car to run well, what would that part be called so I can find one and have it welded in?


Hey Snekdak, I noticed mine doesn't have the connector either. Did you find out what part is needed?
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