New Fuel Lines Leaking; Pressure build up in tank

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FLGordie
Posts: 46
Joined: Sun Aug 07, 2016 1:06 pm
Your car is a: 1980 Fiat 124

New Fuel Lines Leaking; Pressure build up in tank

Postby FLGordie » Sat Aug 20, 2016 6:04 pm

I changed the fuel lines under the hood of my carbureted 1980 Fiat Spider and I leaks at the carburetor return.. Ugh...

I used fuel line hoses and clamps 5/16" for the supply and 1/4" for the return. The mechanical fuel pump is not in circuit. Only a low pressure electric fuel pump. It leaks at the 1/4" return coming off the carburetor. The check valve is in the right direction. I blew compressed air 2" psi through the 1/4 hose and got air out of the tank. Put the cap on and the compressed air pressured the system and pushed fuel through the entire system and out the carburetor return inlet.

Update.. I changed back to the old hose clamps and the leaks stopped. Ran the car and at high speeds it is starved for gas. When I got home, I had a leak in the supply line right before the fuel pump. I opened the gas cap and the system was pressurized such that it shot out a splash of gas from the cap.

Does this indicate that a charcoal canister is clogged and not venting.

Image

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Last edited by FLGordie on Sun Aug 21, 2016 10:00 am, edited 1 time in total.

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So Cal Mark
Posts: 13839
Joined: Wed Jan 25, 2006 3:45 pm
Your car is a: Fiat
Location: upland, ca.

Re: New Fuel Lines Leaking

Postby So Cal Mark » Sat Aug 20, 2016 8:32 pm

your evap hose has a check valve under the car just in front of the rear axle. I've found 2 plugged valves on cars this week. That will cause pressure in the tank
Mark Allison
allisonsautomotive.com Fiat and Alfa Romeo parts and service. Performance parts our specialty!
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FLGordie
Posts: 46
Joined: Sun Aug 07, 2016 1:06 pm
Your car is a: 1980 Fiat 124

Re: New Fuel Lines Leaking; Pressure Build up in Tank

Postby FLGordie » Sun Aug 21, 2016 10:00 am

Mark,

You have found a third! That was the problem. See picture. Completely plugged up. 12 years of sitting up old gas varnish.

Thanks for the solution.

Image

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So Cal Mark
Posts: 13839
Joined: Wed Jan 25, 2006 3:45 pm
Your car is a: Fiat
Location: upland, ca.

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby So Cal Mark » Sun Aug 21, 2016 11:08 am

that valve looks like an archeologist dug it up
Mark Allison
allisonsautomotive.com Fiat and Alfa Romeo parts and service. Performance parts our specialty!
Headers, ignitions, wheels, cams, flywheels
starsmark@hotmail.com 909-981-3566

Fi8spider
Posts: 378
Joined: Sat Jan 03, 2009 7:12 am
Your car is a: 1974 Fiat 124 Spider

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby Fi8spider » Sun Oct 02, 2016 1:43 am

I'm experiencing the same issue where the fuel tank has started to build up pressure.
I have a 1974 which I imported from California. I installed twin 40 DCOE's many years ago and when I did so I plumped in the charcoal canister to the new intake system as per standard. I've never had an issue until recently.

I have searched for the check valve along the clear Cavis fuel pressure relief line and I have not been able to find it to see if that's blocked. The only thing I have found in the clear line is a 5/16 straight joiner in the trunk where the valve may have been removed by the PO and replaced with a plain straight joiner.

The one question I do have if anyone with a 74 can confirm is if the check valve as pictured above is found in the trunk?

BTW, if you are wondering. I have disconnected the line going into the charcoal canister and disconnected the line at the said joiner and tried to blow air through it but it seems blocked.

Cheers

FLGordie
Posts: 46
Joined: Sun Aug 07, 2016 1:06 pm
Your car is a: 1980 Fiat 124

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby FLGordie » Fri Oct 28, 2016 7:02 pm

It is located under the car in the return fuel line above the back axle driver side.

PhillySpider
Posts: 325
Joined: Tue Apr 26, 2016 6:51 pm
Your car is a: 1980 Spider 2000
Location: New Hope, PA

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby PhillySpider » Wed Jun 21, 2017 1:26 am

I have heard what I thought was a slight inrush of air into the tank when opening the cap. Today filling up when I removed the gas cap air popped it off the fill neck high enough that it came down on the rear bumper and rolled across the ground! I had a look underneath before searching here and found what I thought was a fuel filter. I'll definitely be on the hunt for this thing tomorrow...anyone got a pic of a new one or link to purchase? Not sure from the fossil above what I'm looking for :) Thanks!

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spiderdan
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Your car is a: 1968 124 Sport Spider
Location: Ottawa, Ontario, Canada

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby spiderdan » Wed Jun 21, 2017 8:47 am

PhillySpider wrote:anyone got a pic of a new one or link to purchase? Not sure from the fossil above what I'm looking for

https://autoricambi.us/products/fuel-vapor-check-valve
Dan
1968 124 Sport Spider
"Angelina"
2015 Toyota Camry XSE (hers)
2016 Jeep Wrangler Sahara Unlimited (cottage toy)
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PhillySpider
Posts: 325
Joined: Tue Apr 26, 2016 6:51 pm
Your car is a: 1980 Spider 2000
Location: New Hope, PA

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby PhillySpider » Wed Jun 21, 2017 10:11 am

Thanks, found it! Just need to figure out how to remove it. I have some slack, should I just cut or does anyone know a trick to remove the clips and get the 40 year old barb fittings free from the hose?

Ravq124
Posts: 9
Joined: Wed Sep 20, 2017 3:34 am
Your car is a: 1978 fiat 124 spider

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby Ravq124 » Thu Jan 04, 2018 7:39 pm

I just removed my vapor valve and it was full of grey muck, can anyone explain the best way to clean it out?

architect
Posts: 321
Joined: Thu Jul 21, 2016 9:48 am
Your car is a: 1978 Fiat Spider
Location: Austin, Texas

Re: New Fuel Lines Leaking; Pressure build up in tank

Postby architect » Fri Jan 05, 2018 11:47 am

Ravq124 wrote:I just removed my vapor valve and it was full of grey muck, can anyone explain the best way to clean it out?


Simple. Toss it and buy a new one. They are cheap from the vendors
78 Fiat 124


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