Trying to blow fuel lines out with carb cleaner, 1980 pickup (1 Viewer)

[caladin]

Trying to blow fuel lines clean with carb cleaner

Going from fuel filter end toward tank(which is out)

Built a cap to hole pressure in, keeps blowing off.

Is it clogged, or is there normally a check valve in the line?

Should i blow them out tank to carb, or carb to tank direction?

Thanks

 

[ntsqd]

More than once I ran my '84 out of fuel and had to use compressed air to get fuel up to the pump. The original Toyota pump didn't require this, but the successive aftermarket replacement pumps did. No check valve that I know of.

On that '84 the fuel filter was on the frame rail under the bed near the tank and I believe it was all rubber hose between it and the tank. That true in your case too?
If so, I strongly suspect that the inside of the hose has embolisms in it and should be replaced. Modern fuel eats older hoses in particular and it is somewhat common for them to develop loose flaps of rubber inside. Which can all kinds of erratic behavior.
Strongly suggest buying the EFI "Emissions Barrier" type hose. It is a lot more expensive and it is worth every penny of the difference towards not having this sort of problem again.

 

[caladin]

Thanks!

Replaced the rubber, metal lines were full of dried up gas.

Filled them with carb cleaner repeatedly, and put compessed air to 'em