how to prime my fuel system?

[911t Fanatic]

Recently i have been trying to start my barn find 914 and i sorted the wiring to get power to the pump, which i have. Then i noticed the pump didnt work. tore it apart and cleaned the varnish that was once fuel, now it works. I have at one point bad gas in the tank. I really dont want to remove the tank. I have no fuel in the tank or lines. My qeustion is, if i put fuel in the tank and diconnect the supply and return lines at the bottom if the tank, will i get fuel from both or just the supply fitting? If so how am i going to get the fuel pump to pull fuel if all the lines are to have fuel in them? can i somehow prime the system? 1.7 fuel injection by the way. I dont want to mess up the injectors either. Anyone have the same problem in the past?

[Dave at Pelican Parts]

If you disconnect the lines from the bottom of the tank, you'll get fuel from both. There is no valve built in to either line. If the fuel level is very low, one or the other of the fittings may stick up above the level of the fuel, but that's the only way I can think of that you'd get no fuel from one or the other. Unless they are plugged up somehow.

I have had no issues just hooking up the pump and running it; it seems to gravity-prime well enough.

--DD

[Jared at Pelican Parts]

If the fuel in the pump turned to varnish, you would most certainly have to pull the tank to clean it out. Pulling the tank isnt that hard...

If the pump works and you cant get fuel at the engine bay, there is a blockage. I would suspect a combination of bothe varnish and rust at the small "sock" filter on the bottom of the tank.

[911t Fanatic]

im going to partially fill the tank to see if i get fuel out of both fittings.

[Tobra]

It is really easy to remove the tank. I would recommend doing it and cleaning it out if the fuel pump was that bad. That stuff will gum up your fuel filter, maybe end up in your injectors

[jess p]

It's going to be difficult in that if the fuel in the pump became varnish then so
Did the fuel in the injectors and the cold start valve.
Carefully remove those 5 injectors and have them professionally cleaned
Or replace them with new ones.

[911t Fanatic]

Luckily the engine was rebuilt and no fuel went to the system. Found my fuel lines from the pump forward clogged and the fittings coming from the tank. Have fuel coming out of the tank but not the lines. Will be adressing that after work.

[911t Fanatic]

getting fuel to the pump. just wont pull the fuel to the engine bay

[Tobra]

is the pump hooked up correctly to the hoses? I know it sounds like a stupid question

[911t Fanatic]

Im taking the pump out today and run through clean fuel.

[911t Fanatic]

pump is toast. and they are not available. sent it to auto atlanta for a rebuild for 256 bucks aaaghhh. oh well. also removed the tank and im going to restore it. por 15 makes a great kit. no since taking any chances on ruining another pump or worse the injectors

[Jared at Pelican Parts]

Originally Posted by 911t Fanatic

pump is toast. and they are not available. sent it to auto atlanta for a rebuild for 256 bucks aaaghhh. oh well. also removed the tank and im going to restore it. por 15 makes a great kit. no since taking any chances on ruining another pump or worse the injectors

You could have also used the later pump off the 75-76 cars and relocate it to the front trunk. It's a better setup anyway as it removes the pump from the heat of the engine.

[911t Fanatic]

Thanks Jared, wish i had that info before i sent my pump away! Ill keep that in mind for later.

[Dave at Pelican Parts]

And any 12V fuel pump that delivers enough volume and pressure will work just fine. As long as it isn't pushing out so much fuel that it overwhelms the regulator.

--DD

[little greencar]

dump manufacturers prescribed dosage of injector cleaner into tank; as per amount of gas in there. If feul pump runs, run it a while to circulate throughout system, let soak overnight.

Pull injectors up out of their mounts just enouph to set them back down into tea cups with injector cleaner; straight. Let them soak overnight.

If sock in tank over supply line outlet is jamed with fine rust /silt you can detatch supply line at feul pump and blow it back into tank risking blowing it right off the nipple, I guess; so if there is alot of blockage with this you're gona have to clean tank anyway.

Get new filter for when your all cleaned up ofcourse. be carefull of residual preasure in lines; even supply line has gravity behind it's contents; you can temperarily shut down a rubber feul line by pinching it with a set of small vise grips but not the hard plastic ones. You risk cracking old hard rubber and will have to replace. After the feul pump supply you've got residual high presure feul so be carefull. best of luck

Depending on the year of your 1.7; 70-74's the supply line from your tank is bigger than the return line; 9mm/7mm respectively. Only the supply line has a sock screen filter on it in the tank .A reducer length of hose between the supply fuel line and the filter back by the engine where the pump was originally located. All other's have both 7mm lines (I think).

He's right; the tanks not really that bad to take out but you got to deal with the gas and is generally a nervious job worryen about what the neibors will think of the gas smell in the air.

Take all this with a grain of salt. However good my intensions the memory is getting alittle weak. investigate, concure; good luck

[911t Fanatic]

verified throttle switch is working, injectors are clicking as i open the butterfly. Set the dwell and timing, just doesnt seem to accelerate ok. I have not verified my fuel pressure yet so that is what im looking at next. Got to get a pressure gauge first. I suspect low pressure.