evaporative emissions renewal

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miker
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evaporative emissions renewal

Post by miker » Thu May 09, 2019 1:40 pm

I have never touched my evaporative emissions system, and I suspect it is not working. I develop a vacuum in the gas tank after a long drive, there is a woosh! when I open the gas cap.

All the bits are there, but I suspect the check valve (even at $110, unavailable).

Has anyone retrofit their '77ish to the later system? Those parts are available, and pretty inexpensive.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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bartigue
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Re: evaporative emissions renewal

Post by bartigue » Thu May 09, 2019 3:37 pm

Sure, it's really straightforward. Look at the system on the 79 - not all the vacuum lines, just the tank/canister stuff, and it's very simple. The "pull through" type canister they used in the later years does a good job and you won't end up with the tank pressurization issue.
-----------------------------------------------------------
Brad Artigue
1969, 1969, 1970, 1979, 1980, 1981, 1982, and 1982 124 Spiders
1969, 1970 850 Spiders
77 X1/9
http://fiat.artigue.com
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miker
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Re: evaporative emissions renewal

Post by miker » Wed May 15, 2019 4:51 pm

I have the two diagrams side by side (before/after 1978). The valve I have is listed as "check valve/pressure relief valve" and the simpler replacement is just a "check valve". Is there something else in the later system that serves as a pressure relief, e.g., would I need the later canister? The last piece, the separator, seems much simpler in the newer system.

Midwest Bayless suggests that I might just have collapsed vapor hose, since they are original. I recall that when I changed all the active fuel lines, I avoided the vent lines because KD said that nylon check/pressure relief valve is really fragile at this age.
MikeR (mirafiori.com since 1995)


1977 Fiat 124 Spider
Previously owned:
2012 Fiat 500 Prima Edizione #236 (now owned by my son David)
'86 Bertone X1/9
'81 Fiat Spider 2000 #236
'78 Fiat 131 four door
'76 Fiat 128 4 door
'74 Fiat 128 4 door
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davedecker4
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Re: evaporative emissions renewal

Post by davedecker4 » Sat May 18, 2019 11:08 pm

Yes, if redoing the system you should replace the hoses with new ones that wont be collapsed, cracked, swollen or leaking.
That would be the most important part.
Dave Decker
a 'couple' Fiats and Lancia's
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