Fuel check valve
Fuel check valve
For years now I have been tolerating the slow starting after my car has stood unused for a few days or more, although it does always start, eventually. I've done some research on the forum and on-line and the majority of solutions appear to involve mounting an additional electric fuel pump.I was surprised to find very little about adding a one way check valve to the fuel line between the pump and carbs to prevent fuel from running back, although the market seems to offer many types. I have read that there is a danger of fire because leakage has occurred with a specific manufacturer, however I'm thinking that if the valve is located close to the pump then if there is a leak it would not come into contact with heat. Do I miss something ? Are there other aspects to consider when fitting this to a Fulvia ? Some guidance would be appreciated before I do something stupid.
Bryan
Re: Fuel check valve
Hi Brian
The original mechanical pump does have a fuel valve. It does have two in series in fact. They are sensitive to dirt. You may have t clean them and add a filter before the pump.
An alternative to the electrical fuel pump is a rubber ball as used for outboard engines. It can be connected in series with the mechanical pump.
I am not really in favor of the electrical pump. It is usually wired in such a way that in case of accident it keeps pumping. If you insist on putting an electrical pump, I would mount it in series with the original pump and connect the plus to the switch of the choke lever. To start you pull the choke lever. When the carbs are full you start and then return the choke lever. The car then runs on the original mechanical pump.
Also check the fuel pressure when you have everything in place. Most 1.3S and later carbs need 0,2 bar of fuel pressure. Series 1 does have a pressure regulator. Series 2 and 3 have a calibrated hole in the fuel return connection of the banjo.
The original mechanical pump does have a fuel valve. It does have two in series in fact. They are sensitive to dirt. You may have t clean them and add a filter before the pump.
An alternative to the electrical fuel pump is a rubber ball as used for outboard engines. It can be connected in series with the mechanical pump.
I am not really in favor of the electrical pump. It is usually wired in such a way that in case of accident it keeps pumping. If you insist on putting an electrical pump, I would mount it in series with the original pump and connect the plus to the switch of the choke lever. To start you pull the choke lever. When the carbs are full you start and then return the choke lever. The car then runs on the original mechanical pump.
Also check the fuel pressure when you have everything in place. Most 1.3S and later carbs need 0,2 bar of fuel pressure. Series 1 does have a pressure regulator. Series 2 and 3 have a calibrated hole in the fuel return connection of the banjo.
Re: Fuel check valve
Hi Huib,
Many thanks for your detailed reply. I have no plan to add an electric pump because I don't like the idea, but I thought the valve would be a simple modification which can be easily reversed. The idea of an outboard motor type of solution is a novel idea, but I guess the starting point is to clean the existing pump and see if that makes a difference. There is a filter on the car but I cannot recall if it is upstream or downstream of the pump.
Many thanks for your detailed reply. I have no plan to add an electric pump because I don't like the idea, but I thought the valve would be a simple modification which can be easily reversed. The idea of an outboard motor type of solution is a novel idea, but I guess the starting point is to clean the existing pump and see if that makes a difference. There is a filter on the car but I cannot recall if it is upstream or downstream of the pump.
Bryan
Re: Fuel check valve
Looked more carefully at my car and it does have the standard Fisca filter/regulator after the pump. I also found the description on the Fulvia CDs after a long search. As everything is working fine apart from the starting after a long stand I think I will leave it alone until more pressing work is needed. Access is not so good and probably involves removing several parts that are in the way, including the bonnet and this will take me off the road for longer than I would like.
Bryan
Re: Fuel check valve
Right.
The fuel evaporates from the float chambers in the carbs. If you use the car every few days, it starts quickly. After two weeks or longer, the float chambers have to be filled. Takes some cranking time. If the fuel delivery system is still 100% efficient it is not that bad. Remember that cranking the engine also pumps oil around.
The fuel evaporates from the float chambers in the carbs. If you use the car every few days, it starts quickly. After two weeks or longer, the float chambers have to be filled. Takes some cranking time. If the fuel delivery system is still 100% efficient it is not that bad. Remember that cranking the engine also pumps oil around.
Re: Fuel check valve
Looks like there is also a plus from initial cranking and it hasn't got any worse in the last 31 years so I guess it will go on a bit longer ! Thanks Huib.
Bryan