CIS Fuel Problem.

[jpereira]

Hi, I have a 1978 Porsche 911 with CIS injection. The problem is, the car has been sitting for a few years before I bought it and while I have had it has been siting while I did a full restoration. So the problem? The fuel pump relay was not engaging the pump so I jumped the terminals in the relay housing #30 to#87 to get the pump to work and it does. But if I put the new relay in the housing it still does not work. Don't know why it does not work??? Maybe its a censor that is bad? I dont know.
Problem #2 Upon jumping the fuel pump to get it to work, now it works when I turn on the ignition and it feeds the injectors. But, it feeds them while the air plate is closed. It should not feed fuel if the air plate is closed which leads me to think that the fuel distributor Plunger is stuck in the open position and it floods the engine with fuel. But why is it stuck in the open position??? One would think it would be tuck in the closed position???? Anyone out there know how I can fix these two problems or is it something else I have not thought of?????
Thanks

[gomezoneill]

When you lift the fuel plate does the fuel pump run? Fuel spraying while the plate is in the down position could be the setting on the 3mm allen mixture screw is too rich or a stuck plunger could be at fault.

[ossiblue]

Originally Posted by jpereira

Hi, I have a 1978 Porsche 911 with CIS injection. The problem is, the car has been sitting for a few years before I bought it and while I have had it has been siting while I did a full restoration. So the problem? The fuel pump relay was not engaging the pump so I jumped the terminals in the relay housing #30 to#87 to get the pump to work and it does. But if I put the new relay in the housing it still does not work. Don't know why it does not work??? Maybe its a censor that is bad? I dont know.
Problem #2 Upon jumping the fuel pump to get it to work, now it works when I turn on the ignition and it feeds the injectors. But, it feeds them while the air plate is closed. It should not feed fuel if the air plate is closed which leads me to think that the fuel distributor Plunger is stuck in the open position and it floods the engine with fuel. But why is it stuck in the open position??? One would think it would be tuck in the closed position???? Anyone out there know how I can fix these two problems or is it something else I have not thought of?????
Thanks

First, I believe you made a typo. Jumping 30 and 87 will not make the pump run with the ignition on because 87 is the connection to the starter circuit which is only powered when the starter is cranking. You likely jumped to socket 87a.

Now, if you replaced the relay and the fuel pump doesn't work, that may be normal. When properly working, the pump will not run with the ignition "on," only when the engine has started.

Run this quick test and report back. Turn on the ignition, go to the air intake and gently lift the sensor plate inside. Does the pump begin to run with the plate lifted? if so, things are correct. Be sure the brown/black wire from the air flow sensor is connected. It is located near the plug of the engine wiring harness, where the plug is inserted into the rear of the electrical panel. It is a separate wire that exits the wiring harness and has its own single connector.

As far as the injectors shooting fuel, that is another issue. It could be the sensor plate is not fully resting on its stop, or the plunger in the fuel distributor is gummed up and is not fully closing the fuel ports. It could also be the mixture screw has been adjusted too much and the plunger is not fully closed. My point is, you will need to investigate the mechanical elements of the air sensor arm, fuel distributor plunger, and fuel distributor itself. In the meantime, be very careful when testing your fuel pump as each time it runs, fuel is being injected into the cylinders.

[T77911S]

when you lift the plate as ossi said, you should IMEDIATELY feel resistance against the plate, if there is ANY free movement before resistance then the plunger is stuck in the up position. this happens frmo sitting.
jsut pull the head off and carefully pull the plunger out and clean it along with the inside of part it slides in,

[Bob Kontak]

Originally Posted by jpereira

Plunger is stuck in the open position and it floods the engine with fuel. But why is it stuck in the open position???

I could see the bore just above the plunger getting some gunk build up in it. A little varnish, a touch of oxidation, who knows. It may have slid upwards the "first time" and became bound.

Good input from the above guys.

If you do pull the top, which I have never done, I understand you carry it like a new born baby - don't let the plunger drop out. No pliers, etc. Bore and plunger are matched.

[don gilbert]

Dont spit the fuel dist. until last resort. You can bang the crap out it, wont hurt it.

[boyt911sc]

Originally Posted by jpereira

Hi, I have a 1978 Porsche 911 with CIS injection. The problem is, the car has been sitting for a few years before I bought it and while I have had it has been siting while I did a full restoration. So the problem? The fuel pump relay was not engaging the pump so I jumped the terminals in the relay housing #30 to#87 to get the pump to work and it does. But if I put the new relay in the housing it still does not work. Don't know why it does not work??? Maybe its a censor that is bad? I dont know.
Problem #2 Upon jumping the fuel pump to get it to work, now it works when I turn on the ignition and it feeds the injectors. But, it feeds them while the air plate is closed. It should not feed fuel if the air plate is closed which leads me to think that the fuel distributor Plunger is stuck in the open position and it floods the engine with fuel. But why is it stuck in the open position??? One would think it would be tuck in the closed position???? Anyone out there know how I can fix these two problems or is it something else I have not thought of?????
Thanks

JP,

There is a thread about the FP relay and socket test posted by DKLever48. Search and read it until you get the gist of the tests. Everything you need to know about the FP relay operation and tests were discussed in that particular thread.

Now with regards to your FD prematurely delivering fuel to the injectors before the engine starts could be caused by:
a). FD plunger is stuck open thus allowing fuel to flow through.
b). The mixture setting was set too RICH to a point that it allows fuel to be delivered prior to start.
c). Leaking o-ring/s inside the FD. If one (1) or more injectors are prematurely delivering fuel, that is a good indication that the o-rings are defective and leaking. Unless all six (6) o-rings are leaking, the fuel flow would be like a stuck up plunger.

Tony

[sc_rufctr]

In the OPs situation I would be tempted to take it to a specialist to get it working properly.
... It's just too easy to damage a CIS system by trying to DIY it.

The best thing you can do for a CIS engine is to drive it. When they're working well they're a great FI system.
Over the years lots of people have rubbished the CIS system but IMO it's more than fine when in good order.

[jpereira]

You Guys are great!!!!!
I took the information you gave me and I Identified the problem....
The Fuel relay is now working it was a bad connection on one of the terminals and the CIS cystem I followed the instructions and found that the Plunger is stuck.
Next steep is to remove the fuel distributor and soak the plunger to remove bad fuel Varnish...

[T77911S]

just pull the plunger out and clean it with carb cleaner.
i am not a fan or spraying carb cleaner in the sleeve the punger rides in because there are rubber O rings inthere that you dont want to mess up.
i think some have soaked the head in techron.

dont drop the plunger.