Fuel in cylinders with CIS

[mspirito]

I just purchased a new car drove it 800 miles without any problems. The engine is an SC engine with CIS. I was working on the electrical system and had the key in the on position with the fuel pump running. I went to start the car and it would not turn over. It feels to me like a carbureted car that has filled the cylinders with fuel, Is this a problem that is possible with the CIS's system?? The starter engages and attempts to turn but does not move??

[Laneco]

YES.

You are hydrostatically locked. Shut all electrical down, disconnect the battery (to avoid any possible spark), remove the plugs and turn the engine by hand. The gas will come out of the spark plug holes.

Dry everything up tidy and nice before you start it. You should also change your oil as it is possible that it is now fuel contaminated.

Your starter isn't strong enough to damage the engine. But if you try to roll start it, you will shove a rod through a piston or some other similiar and horrifically expensive mechanical failure. Basically, the piston can't go all the way to the top because of the gasoline in the cylinder. Something will bend or break in the attempt to force it.

angela

[Scott R]

A hi-torque starter can do rod damage on an SC. But on to more pressing issues, why was the fuel pump running with the key in the "on" position? Did you have the relay bypassed?

[timmy2]

Even more worrisome is why fuel would flow into the cylinders even with the pump running for whatever reason.
Shouldn't go anywhere except back to the tank until the distributor plunger is lifted. (Airflow lever up)

[fanaudical]

Agreed - probably have filled the cylinders with fuel.

Depending on model year, there may not be a fuel pump relay. I know my '75 will run the pump continuously while the ignition is on.

[47silver]

on our 75 the fuel pump runs when the key is on but flow does not go to the injectors unless the engine is turning over and there is air flow across the air flow plate.

what year is your cis?

[Jaybird12]

Originally Posted by 47silver

on our 75 the fuel pump runs when the key is on but flow does not go to the injectors unless the engine is turning over and there is air flow across the air flow plate.

what year is your cis?

Does your '75 have a fuel pump relay? My pump is located in the rear and there is no relay for it anywhere I can see. Should I install one? What signal shuts down the relay?

[E Sully]

mspirito,
You say the engine is an SC, but you don't say what year the car or the engine is. An SC engine would have an electrical connector to the air flow plate that would activate a fuel pump relay. If the engine is in an early car there is no fuel pump relay or fuse and the fuel pump comes on when the key is turned to the start or run position. If the air flow plate is set correctly and the injectors are good, no fuel would flow through the injectors till the air flow plate is lifted. A little more information is needed.
Jaybird,
Your car is like my 1973 CIS, no fuse or relay. The air flow plate has no provision for the electrical relay switch. You can install a fuse inline to protect the fuel pump though.

[don gilbert]

Pull the plugs, have someone spin it with the starter, see which holes the gas comes out of, prob, just got a drippy injector or two.

[Jaybird12]

I was thinking about installing a fuel pressure gauge for quick reference. What range should a 75 CIS be running in?

[E Sully]

WUR specs2

[Nostril Cheese]

After you drain the fuel from the cylinders, take the air filter off and check that the sensor plate in the fuel distributor squeals when you lift it up for a second. Key must be on.

If it doesnt squeal, you probably have a stuck control piston in the fuel distributor. This would also explain why the cylinders are filing up with fuel.

[mspirito]

Thanks for the help. It is a 3 liter in a 1971 so I need to investigate the relay question and the fuse issue as there is no fuse in the fuse box for the fuel pump. I'll certainly try the squeal test.