Fuel system drain back.

[Vintage Grumble]

HI! What would be a likely cause of the fuel pump/lines in my lada draining? If its parked nose up, or not used for more than a few days, I have to hand prime the pump to get gas up thar. It also makes girgling/sucking/fuel running sounds nearly all the time. Would a blocked breather cause this sort of tomfoolery? If the breather was blocked, and the tank cooled down at night, I guess it could suck the gas back up the fuel line into the tank, and then when it expands again, it may not have the ability to push it back up the line again?

Regards, VG.

[azzurro]

my Fiat does the same thing - if its been sat for a while the engine has to be cranked for quite a while so the mechanical fuel pump (on the engine) can draw fuel back up from the tank again and will run rough for a while untill all the air is gone.

I just supposed it was just lack of a one way valve of some description or another in the design of the fuel system.

A blocked breather would exacerbate the issue by creating a suction/siphon in the tank as its level drops and though temp changes, but also affecting engine running though fuel starvation (pump can overcome vacuum in tank esp via a long run of small ID pipe) if its blocked bad enough.

If its like my fiat, the breather will be a pretty long looped lenth of pipe off the tank sender/top of tank venting into the rubber under the fuel filler flap. Just replace it and/or clean it out.

You can probably get inline fuel filters with a one way valve?

[Vintage Grumble]

I'll see if the breathers blocked, and if its not, i'll look into putting a one way valve down by the tank. Its no biggy really, pump has a manual primer on it, i'm just lazy, lols.

[Seedy Al]

Or maybe try putting a loop in the fuel line or something so that it is higher than the pump...?

[Vintage Grumble]

The pump is near the bottom of the block, and the tank is in the boot, so I dont know if that would work?