1977 911S Fuel Lines Cut

[74threeliter]

Hello,

I am trying to help a fellow porsche owner with the fuel lines to his 1977 911S. I was wondering if anyone out there knows or has an image to share of how the fuel lines run for a 1977 911S equipped with the 2.7 liter engine. From what i can tell some one cut the hose line coming out of the Fuel Accumulator as Image 1 depicts. Image 2 displays another line that also looks cut and from what i can imagine also T's off with the Fuel Accumulator line. The size of the hose on Image 2 seems really thin and is not using the correct clamp (an oversized one - crunched to squeeze/compress line to fitting). Does anyone have a fuel line schematic or pictures showing a 1977 911S fuel delivery system. Car cranks with starting fluid.

[tadel001]

It is hard to tell from this picture but it appears you have a 3.0 accumulator, i.e. 2 ports on the top and one coming out the bottom. The '77 2.7 would have fuel line from the tank to the accumulator than to the filter than to the engine. That s-metal tube also is consistent with a 3.0 not 2.7 set.

[74threeliter]

That is what contributed to my confusion. I thought the Fuel Accumulator looked different. That is probably why the hack job occured in an attempt to install a different year fuel acumulator. So the 's-metal' tube your referring to is the one that is coming out of the fuel filter and into the fuel accumulator... right? ok so the important sequence here is fuel line from fuel pump up front goes to accumulator then the second line from the accumulator goes to the fuel filter then that line goes to the fuel distributor? or does it 'T' off with a cold start valve?

I am going to source the correct fuel filter and fuel accumulator parts and start from there...

[74threeliter]

Second set of images of another line cut and the 'T' fuel line.


Better shot of 'T' line:


Same just zoomed out:

[boyt911sc]

Al,

The 'cut' hose that is connected to the bottom of the FA is the drain or return line. Connect it to the tee (return line to the tank). Normally, the fuel accumulator is attached at the tee (where the WUR return line is connected now, shown in picture) and the WUR return line is connected to the FD (fuel distributor , rear side).

Are there two (2) connections at the tee? If yes, then that's where the FA drain line goes.

Tony

[j_mancini]

Not certain if this will help or not, but here's a fuel flow schematic. Looks like mid-year setup to me (don't quote me):

[boyt911sc]

Originally Posted by tadel001

It is hard to tell from this picture but it appears you have a 3.0 accumulator, i.e. 2 ports on the top and one coming out the bottom. The '77 2.7 would have fuel line from the tank to the accumulator than to the filter than to the engine. That s-metal tube also is consistent with a 3.0 not 2.7 set.

Tim,

The metal S-fuel line is the common connection for CIS FA-fuel filter set-up for '76-'83 CIS engines. This is not exclusively used in SC's. The '74-'75 have this configuration but uses 2 port FA while the SC's have the three (3) port FA. The bottom port is the drain line connected to the main return line at the tee-junction shown in the pictures.

Tony

[Flat6pac]

The 77 has a 3 port accumulator and the bottom is a safety device so if the diaphram in the accumulator leaks the fuel returns to the tank instead of catching fire as in the 74/75, I just cant remember 76 so I didnt include it
The line coming off the accumulator and the plastic line coming off the return line @ the connection is the same line.
Bruce

[74threeliter]

Thanks to all for the information it seems this is vehicle carries the correct 3 port FA and the lines cut are to connect and make a return of fuel back to fuel tank. Now the tackling issues lie with the fuel injectors and fuel distributor. Does anyone know of a Fuel Injection Specialist for Los Angeles area? Should i ditch the clean job and go for new? How much is a used Fuel Distributor for a 77 911S? Appreciate all the help.

[74threeliter]

Pulled the fuel injectors and 3 are rusted/clogged the other 3 are just clogged. Wondering if these are worth saving/cleaning...

[Flat6pac]

For the price of a new or rebuilt you should be able to find a whole FI system and have money left over.
Bruce

[T77911S]

with injectors that bad, the whole system may be screwed. this may help you decide.

remove all 6 injectors. place the 6 lines in 6 containers. turn the key on, raise the air sensor plate. you should imediately feel resistance. as you lift the plate, more fuel should come out of the lines. then figure out a way to measure the amount of fuel in each container. when i did mine, i poured each one into a common container then weighed it on a postal scale. what you are checking for is equal fuel delivery. small amounts of difference are ok, large amounts are not. i found one line was putting out half as much as the others. this could help determine if the FD is good. i think it is tony that has a nice little setup for this. i just used 6 big plastic cups. if this is good, 6 new injectors and then its on to the warm up reg and control pressure.

oh, i would first do a FP test. test for pressure and volume.

[74threeliter]

Hi,

-removed all 6 injectors and placed each in their own water bottle container (made hole on caps)

-turned the key to the on position and listened for the fuel pump to come on
(heard a whining sound coming from under the intake boot)

-lifted the sensor plate (there was no if any resistance at all) - I think this is where the larger problem is!

should the fp test be done between the wur and the fuel distributor? or prior to the wur?

[T77911S]

if you felt no resistance and the FP was running, then the plunger is stuck in the FD. this is common when the car sits.

[74threeliter]

Thanks i will take a look at the fuel distributor for proper flow i believe it is also clogged. The 3 fuel injectors found as rusted looked really bad. Are there just the 3 bolts holding down the fuel distributor? or is it really difficult to remove with it in the vehicle?

[boyt911sc]

Originally Posted by 74threeliter

Thanks i will take a look at the fuel distributor for proper flow i believe it is also clogged. The 3 fuel injectors found as rusted looked really bad. Are there just the 3 bolts holding down the fuel distributor? or is it really difficult to remove with it in the vehicle?

Al,

Do you have a FI fuel pressure gauge kit? You need one specially for the kind of work you are doing. A new kit costs about $60 from JC Whitney and would pay for itself the first week of usage. Or borrow one from a local friend.

You need to establish first the integrity of your FP and the system pressure set for the FD. The rest will fall in place as you go along your investigation. Without knowing the fuel pressures would be a setback for your investigation. The lack of familiarity with CIS troubleshooting could be overcomed by simply asking the right question/s.

Be very careful when you try to remove the fuel distributor from its mounting. The plunger underneath the FD is a precisely machined part and accidentally nicking its surface means big time problem. Take extra precaution and awareness for the plunger from falling to the floor!!!! Keep us posted.

Tony

[j_mancini]

Originally Posted by 74threeliter

Thanks i will take a look at the fuel distributor for proper flow i believe it is also clogged. The 3 fuel injectors found as rusted looked really bad. Are there just the 3 bolts holding down the fuel distributor? or is it really difficult to remove with it in the vehicle?

When I've taken the fuel distributor off the air flow sensor, those 3 bolts (standard screwdriver slot, not hex head) have been VERY tight! Doing this while still in the car may be a real challenge. A partial engine drop will get you some room to work.

[74threeliter]

Thanks i saw the 3 bolts but also thought there could be more. Thanks for the confirmation "John". Currently looking into finding time to do a partial lower of the engine and remove the fuel distributor. An order to the host for new injectors/sleeves/o-rings has been made. I was not able to locate an entire FI system. If anyone has a clean FD to sell please contact me. I'll be entertaining myself with Projects 101 engine drop instructions complimented with the Bentley Manual.

[unclebilly]

I have a complete CIS system from a 75 for parts. $350+ shipping.

The accumulator was replaced recently.