Fuel Delivery Options

[lsintampa]

75 914/4 2.0

Most drawings on fuel delivery that I can find show the fuel pump having three ports. Mine has only two ports (inflow and outflow).

Gas tank and motor are currently OUT of the car.

Looking in the front trunk, there are two fuel lines running to the engine bay. Outbound and inbound. Which of those two are sending fuel to the motor and which one is the return?

Same question on the tank itself. There is a skinny sock filter on the inside of the tank, I'm guessing that is the line sending fuel out of the tank to the motor, correct?

Thanks,

Len

[JamesM]

75-76 2 port pump in the front trunk was stock. The tank line with the sock runs to the pump. I believe the drivers side line is the return line. On the early cars it was the smaller of the two but on the late cars they are the same size so in reality it probably doesent matter. Hopefully you are replacing them with stainless.

[914itis]

Have Fun!

[r_towle]

starting at the tank.

Line with the sock is the sending line, feeds pump.
Pump mounts under the fuel tank on your car, drivers side.
Filter mounts against the wall, there should be clips for a square filter that I recall is NLA...but a BMW filter can be used, it has the same size ports.

So, fuel comes out, goes into the filter, then the pump, passneger side of the pump.
Out of the pump, drivers side, loops down to the fuel line at the tunnel.

The feed line comes out of the tunnel and connects to the passneger side fuel rail, so from the tunnel it goes rubber, then again to plastic, then rubber at the passenger fuel rail.

The return line goes up to the engine bay right next to the feed line, but it connects to the system after the cold start injector and loops and remaining fuel back to the tank.

rich

[lsintampa]

I think I have it....

I'm picking up my tank today - just got it resealed / painted, etc.

Where does the small 5mm vent line terminate in the engine bay? To the canister filter - I assume.

Also, has anyone run high pressure fuel lines through the tunnel? My 74 BMW 2002 had high pressure lines running along the inside of the cabin along the sills and up through the firewall.

Thanks!

[ThePaintedMan]

I think I have it....

I'm picking up my tank today - just got it resealed / painted, etc.

Where does the small 5mm vent line terminate in the engine bay? To the canister filter - I assume.

Also, has anyone run high pressure fuel lines through the tunnel? My 74 BMW 2002 had high pressure lines running along the inside of the cabin along the sills and up through the firewall.

Thanks!

Hey Len,
I don't know about the vent line, as we talked about yesterday. But I'm not sure what you mean about the high pressure lines through the tunnel. Currently, that's how the car is setup - with the lines running through the tunnel. Yours are still the plastic ones, which I think we talked about replacing with stainless. Either way, running them through the cabin is probably not a good idea and I'm surprised BMW got away with it! (IMG:style_emoticons/default/biggrin.gif)

[lsintampa]

I think I have it....

I'm picking up my tank today - just got it resealed / painted, etc.

Where does the small 5mm vent line terminate in the engine bay? To the canister filter - I assume.

Also, has anyone run high pressure fuel lines through the tunnel? My 74 BMW 2002 had high pressure lines running along the inside of the cabin along the sills and up through the firewall.

Thanks!

Hey Len,
I don't know about the vent line, as we talked about yesterday. But I'm not sure what you mean about the high pressure lines through the tunnel. Currently, that's how the car is setup - with the lines running through the tunnel. Yours are still the plastic ones, which I think we talked about replacing with stainless. Either way, running them through the cabin is probably not a good idea and I'm surprised BMW got away with it! (IMG:style_emoticons/default/biggrin.gif)

Meant soft lines - as opposed to hard lines - that is how the BMW ran fuel lines - they were high pressure soft lines - ran along the inside cabin up through the firewall.

[Dave_Darling]

Where does the small 5mm vent line terminate in the engine bay? To the canister filter - I assume.

Yes, that's where it goes. IIRC, there is a small metal pipe coming out next to the fuel lines. That gets a small hose that runs to one of the fittings on the charcoal canister.

--DD

[lsintampa]

Ordered new SS lines today...

Pulled out the old lines - they looked fine - one still had some gas (or what used to be gas) in it

Getting that front grommet out that holds the lines in the front trunk was fun..

[ThePaintedMan]

Len,
Although getting the lines out was a bear, you'll be happy with the knowledge that you've replaced one of the most common and pivotal failure points on these cars... maybe even saved your ride from a "car-b-que" in the future. Would stink to do all the work you're doing and see it go up in smoke...literally (many have been there before). The SS lines will last longer than the car does and you won't have the headache of replacing them with the engine in later.

If you think the grommet was a pain to get out, wait till you have to get the new lines back through it! (IMG:style_emoticons/default/smile.gif)

I will second/third/whatever the recommendation to keep the stock FI intact. Not many cars are running around with it, and had my car's harness not been hacked off when I got it, I might have tried to piece together a FI system for it. Furthermore, if (hopefully you never will) you do sell it, it's one more "plus" to have an original fuel injection system in working order, from what I understand.