injector flowing with key on 76 911S with CIS

[otto_kretschmer]

Hi guys,

havn't posted in a while

I'm trying to get my dormant 76 911S running. Its been sitting for about 8 years.

The engine started and ran this morning, on and off. I checked for spark and it was good. I drained the tank a while ago and installed a new fuel pump. The original was still working but making noise. I routed the return line to a gas can and fuel is flowing like it should.

It won't start now. I pulled an injector and found that injector to be flowing a little fuel with the key on and the engine not running. This may be my problem but I don't know if its the injectors or the fuel distributor.

any ideas?

thanks

[otto_kretschmer]

I pulled 2 more injectors and both are flowing with the key on and engine not running. This makes me think the fuel distributor is the problem. I probably should dump my oil and replace when I get this problem solved.

[scarceller]

Yep, the fuel distributor is likely the cause.

But test again and this time pull down on the air plate slightly, do the injectors stop leaking? You can also push up on the air plate slightly and the injectors should really start spraying fuel.

The slight leak on injectors could also be that the CO screw is improperly adjusted and causing the pin to be pushed in a bit to far with the air plate at rest? This is why I suggest you pull down on the air plate by hand a bit.

[Flat6pac]

The fuel distributor center pin is not coming back to the rest position.
Bruce

[otto_kretschmer]

thanks scarceller,

I have not pulled the air filter off yet. I stopped for lunch. I may work on it some more or go for a ride

[scarceller]

+1 on this. Could be it's sticking or the air plate is to far up for some reason.

Originally Posted by Flat6pac

The fuel distributor center pin is not coming back to the rest position.
Bruce

[OsoMoore]

Also note that, if you only pulled two and they are going, the other injectors have probably flooded their cylinders.
When I was working on my CIS, I picked up 6 baby bottles at the dollar store and numbered them. Stuck an injector in each, and I could do all the testing I needed without flooding cylinders or making a mess.

[scarceller]

Also these bottles are a great way to verify all 6 injectors spray same amount of fuel when you lift the air plate up.

Originally Posted by OsoMoore

Also note that, if you only pulled two and they are going, the other injectors have probably flooded their cylinders.
When I was working on my CIS, I picked up 6 baby bottles at the dollar store and numbered them. Stuck an injector in each, and I could do all the testing I needed without flooding cylinders or making a mess.

[OsoMoore]

Originally Posted by scarceller

Also these bottles are a great way to verify all 6 injectors spray same amount of fuel when you lift the air plate up.

Oh yeah, they worked great. I inverted the bottle nipples and widened their tip holes, and then the injectors fit in snugly. No risk of leaks if they fall over, and no gas fumes.

[otto_kretschmer]

Originally Posted by Flat6pac

The fuel distributor center pin is not coming back to the rest position.
Bruce

Bruce,

is the center pin called a plunger in all the videos I've been watching?

[93nav]

If are driving it, it may be worthwhile to put in a good fuel system cleaner and run at least one tank thru it that way. Cheap and easy.

Edit: I just went and reread your initial post. Car is not running, so never mind.

[ossiblue]

You may have two problems.

Problem 1, your fuel pump is obviously running when it should not. With the ignition ON, the pump should not be running and, therefore, no fuel pumped to injectors. If you find leaking injectors with the ignition ON, you have an issue with your fuel pump relay or you or a PO has disabled the system.

Problem 2, leaking injectors, and that has been addressed by previous posts.

[eastbay]

[boyt911sc]

Originally Posted by otto_kretschmer

Hi guys,

havn't posted in a while

I'm trying to get my dormant 76 911S running. Its been sitting for about 8 years.

The engine started and ran this morning, on and off. I checked for spark and it was good. I drained the tank a while ago and installed a new fuel pump. The original was still working but making noise. I routed the return line to a gas can and fuel is flowing like it should.

It won't start now. I pulled an injector and found that injector to be flowing a little fuel with the key on and the engine not running. This may be my problem but I don't know if its the injectors or the fuel distributor.

any ideas?

thanks

Otto,

If I were in your shoes, this is what I would do:
1). Disconnect all the six (6) fuel lines to the injectors. Then place the ends of the fuel lines previously disconnected from the fuel injectors in separate individual containers to collect fuel in case there is fuel flow.
2). With the six (6) fuel lines properly secured, start the FP and observe for any fuel flow.
a). There should be no fuel flow at this point. This is normal.
b). There is full flow..........either the FD plunger is stuck up or fuel mixture set too RICH or a defective FD.
c). There is partial flow.........FD leaking due to defective o-ring/s.

Determine the condition of the FD before proceeding to testing the fuel injectors. There is no good reason to test the fuel injectors if the FD is defective. If the FD passed the test, proceed the investigation with the fuel injectors installed. Keep us posted.

Tony

[otto_kretschmer]

thanks for all the replies, I think I'm heading in the right direction

I'm deciding if I should go farther into the fuel distributor or wait until my move is done and the car is in my new location. I'd like it to be driveable so I can get it on and off the trailer and move it around without having to push

in the mean time I'll just tease you guys with some garage porn

[otto_kretschmer]

[boyt911sc]

Originally Posted by otto_kretschmer

Otto,

Where are you located? The BMW MC reminds me of someone I met a couple of years ago.

Tony

[otto_kretschmer]

Originally Posted by boyt911sc

Otto,

Where are you located? The BMW MC reminds me of someone I met a couple of years ago.

Tony

somewhere in southern California, I don't like to get too specific on an open forum

on the bike I could be anywhere from Solvang to Tucson

[otto_kretschmer]

that plunger is stuck

and stuck good

now how do I unstick it?

[boyt911sc]

Originally Posted by otto_kretschmer

that plunger is stuck

and stuck good

now how do I unstick it?

Otto,

Your system fuel pressure is about 70 psi. Is it stuck at rest or at an elevated position? Sometimes you could overcome the sliding problem of the plunger by moving it up and down due to some varnish deposit. Many times, you need to disassemble it to gain access to the barrel and piston (plunger).

Tony