Bad Leak. Need Help.

[assman]

I have a 3.3 930 that was running great yesterday. Went out to drive today and noticed a pancake size leak puddle under the center of the muffler.

Moved the car inside and got it in the air. Oil/Fuel was leaking from turbo/exhaust connection and cylinder to header connection.

When ignition is on, it pours fuel.

Did a leak down and it came back solid (less than 5% all around).

Any ideas on where to start or the severity of this issue?

[908/930]

Does your CIS air flow sensor move freely? The flow sensor should shut the fuel flow in the fuel distributer when engine is not running.

EDIT How long did the fuel pump run without engine running? Possibly should also drain the oil out of crankcase.

[gorskined]

Your fuel pump should not run unless the car is being cranked over or it's running ... Sounds like your safety air flow switch for your fuel pumps is disconnected or not set correctly and its only now an issue because you have that injector stuck open on that cylinder ..
The car can operate without issue with the safety switch not working or disconnected not recommended but many cars do . if its only leaking from that one cylinder pull the injector and see if it sprays with just the pumps running if so replace the injector. if they are old you may want to do them all. if all of the injectors are l spraying by you may have a stuck plunger in your fuel distributor . put a cis meter on to confirm pressures .. my money is on a single bad injector.

[assman]

Thanks. I'll give that a shot.

[motorracer]

I don't think these injectors shut off its all in the fuel head but I could be wrong

[gorskined]

Originally Posted by motorracer

I don't think these injectors shut off its all in the fuel head but I could be wrong

They are designed to not flow at a set ps.i off hand I don't recall but I believe it's between 35 and 40 if I remember correctly.

[jsveb]

Not sure about the vintage of your 930. If applicable check the rear round relay. A faulty relay can affect the fuel pump ignition on issue.

[Alan L]

The pumps should not be running. One problem.
Having said that , they should not be pumping fuel to the cylinders - without the engine running. You can have the pumps running but all fuel would/should be cycling back to the tank. It sounds like 2 problems. Pumps on and an injector(s) open. What I would do is pull the culprit area injectors, hook them up externally, and see if they are sraying fuel with pumps on. They should be closed. They should only be opening when the airplate opens - this mechanically opens the metering slits in the fuel head.
So , just double guessing this one - the pumps on has been a previous issue - but not noticed. Until an injector has failed to shut off .
Alan

[spuggy]

FSM gives injector crack pressure for a '78 930 as 2.1-3.2 bar. So ~31-47 PSI are the lower/upper limits of spec.

Things to check for a CIS injector:

• injector opens at correct crack pressure
• Spray pattern is a fine mist in an even cone shape
• check valve works (doesn't leak or dribble)

Any of these tests fail - replace.

[dos531]

The universe is giving you a sign. Throw that cis in the garbage and go efi

[Alan L]

Originally Posted by dos531

The universe is giving you a sign. Throw that cis in the garbage and go efi

Well, not really. Anything can fail. Especially after 40+ yrs. CIS actually works pretty well, but it does take a while to get your head around it.
I would struggle with EFI - because IT technology and me don't get on. You should see my phone.
The CIS is not complicated - when the time is spent figuring it out.
So, I respectfully, beg to differ.
Alan

[quattrorunner]

Assman! That's good. The young-uns won't follow that.
Sorry about the leak.

[PorscheGy]

Same issues with mine

[PorscheGy]

How do I get around this forum?

[mark houghton]

Originally Posted by Alan L

The pumps should not be running. One problem.
Having said that , they should not be pumping fuel to the cylinders - without the engine running. You can have the pumps running but all fuel would/should be cycling back to the tank. It sounds like 2 problems. Pumps on and an injector(s) open. What I would do is pull the culprit area injectors, hook them up externally, and see if they are sraying fuel with pumps on. They should be closed. They should only be opening when the airplate opens - this mechanically opens the metering slits in the fuel head.
So , just double guessing this one - the pumps on has been a previous issue - but not noticed. Until an injector has failed to shut off .
Alan

Beat me to it Alan.
The metering slits have to be open in order to send fuel to the injectors. Stuck plunger maybe or misaligned metering arm hanging up. Tell-tell sign would be audible injectors squealing as soon as you turn the key on.

[gorskined]

if the issue fixed it self, its a faulty injector that that didn't seal . you may be good for years or it way drip intermittently . i would recommend replacing the injector