308 Unidirectional fuel valve #111790; is it needed?

no, i think you have to have the valve in place or the exhaust pulses at high rpm will backflow through the pump and damage it. sucks you have to have airpumps. i have my pair with all the brakects ect in a box somewhere. if you cant find one i will give you my valve for the shipping money if i can find the damn box.


michael


try GT car parts tomorrow.

 

When I first bought my 308 carb it would starve for fuel when going up a long steep grade. Since I just purchased the car I took it back and the Ferrari mechanic checked the fuel pressure output and it was only 1 lb. He removed that oneway valve and found it to be broken/clogged. He said that it was a US safety requirement in case the car rolled and ended on it's roof. Euro cars don't have it he said so he removed it and rerouted the hoses. The fuel pressure was now 4lbs and the car has run OK since.

 

oops, i was wrong... you ARE talking about fuel and not the air pump..... its been a long week for me.... sorry.

worse thing is i just did my fuel lines to the carbs and my fuel filler neck hose 2 weeks ago... i have the valve too.
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About a week after I bought gt4, said valve started leaking, every source (dealerships, TRutlands, etc..) indicated the valve was NLA. So I rerouted the lines myself. The first attempt failed as the pump was basically pressurizing the system but flowing in a loop. The engine would crank and start very briefly then stall. Second attempt was a success with no problems since.

 

Hi
Can you remember where you rerouted these fuel lines to? My car is leaking from the same valve. I recall 3 hoses going to and from this valve. I cannot find a replacement part.
1978 308GTS US model.

Thanks
David

Adelaide Australia

 

Bumping an old thread, as the 1977 GTB that just sold on BAT renewed my hunt. My question was - do I need this part? In another thread, someone claimed that this was in the circuit in case you had an accident. That's all crap.

https://www.ferrariparts.co.uk/Diagram/ferrari/308-gt4-dino-1979/048-antievaporative-emission-control-system-(variants-for-usa-aus-and-j-version)?part=111790

It's there for emissions, so all the fuel in the filter can't evaporate if you don't drive your car. That's why the Euro cars don't include/need it - because they didn't care.

If I ever found one, I'd probably buy it to have a "complete" car, but I'd never install it.

 

Not needed, remove it. It’s purpose is to shut the flow of fuel to the carbs if the hose from the fuel pump to carbs is ripped or has a major leak. They can fail shut and then no fuel.

 

I have removed several after they fail. No problems after that.

 

If anyone has one, please PM me. Like I said, I'd like to have it just to "complete" my car.