1974 CIS Fuel pump runs but no fuel

[Rocket Car]

The fuel pump is running on my 74 CIS, but I am not getting any fuel to the engine. (This is an early CIS with the pump at the rear of the car)

I have loosened the fuel hose where it enters the accumulator. There was an initial spray of fuel, which was under pressure. I then disconnected the hose and ran the pump, but no fuel is coming through. There is gas in the tank

Do these pumps ever fail where they run but do not pump any fuel at all?

Thanks

[allaircooled]

I don't know the inner workings of the fuel pump, but I suggest taking a peak at the fuel tank strainer and see what it looks like. It's accessible at the bottom of the fuel tank. Its a big allen socket but I have a spark plug socket where the bottom of it fits perfectly or you can use a bolt with two nuts to take the strainer out. You can also take off the fuel level sender unit and see if inside of your tank has a bunch of crud on the bottom.

[timmy2]

fuel filter?

[BoxsterGT]

Fuel filter is downstream of the Accumulator.

Here is the Fuel Tank strainer.......



at the bottom of the Tank. Of course you must drain the tank to clean it.

You might check for fuel at the Supply hose above the Tranny.....



It's the one connected to the BROWN Nylon tube (Arrow) that was originally White. (That's another story about the 74 model you should be aware of.)

If no fuel there, then go to the Tank.

Good luck.

Len

[boyt911sc]

Bench test the fuel pump. If the pump passes the test, then test the supply side.

Tony

[TheBrokePilot]

Could you have wired the fuel pump backwards?

[BoxsterGT]

Don't think this is a new installation, just a failure that occurred.

Rocket -

Can you tell us more about your 74 911? Is it stock, as in original?

Have you dealt with the White Nylon Tunnel line issue? If not, then research this through Pelican. You will find some very interesting facts.

Better to be safe than SORRY.....



I know only too well, as I lost my 72 YellowBird to a fire.

Len

[Rocket Car]

Hey all, thanks for the replies.

My Targa was a barn find. It had been parked up in 1984 and never saw the light of day until 2021.

I have replaced the tank and all fuel hoses (including the plastic ones through the car). I got her running and went out for few test drives before it did a lovely backfire and blew the airbox!

Over the summer I have fitted a new airbox, injectors, upgraded tensioners etc.
Before trying to start it again, I turned the ignition to pos 2 in order get to the fuel flowing and check for leaks.
This evening I removed the inlet to the pump
and there is a good flow of fuel from that line.
I have a spare pump so I will fit that and see what happens. I have noticed the pump is slightly wet,
where the main housing meets the end cap.

[Rocket Car]

Update on this - fitted a new pump and all is good!