Need help, 1977 911S

[grim77911S]

will not start. Ran perfect, put it in the garage and a month later it will not start. I have spark at the coil wire & plugs, replaced the fuel pump with OEM new, relay works but still no start. It will start to idle, but dies after a few seconds.
Any ideas ?
The car is all original with 38,000 original miles, new wires plugs coil cap and rotor.
What would make it just die sitting in the garage ?
Thanks in advance.

[T77911S]

i hate to ask this....is it out of gas? i ran out in my driveway once.
if not, then pull an injector and make sure it sprays when turning over.
do you have a popoff valve installed? if not, did it backfire?
did it run AFTER replacing the fuel pump?
did it run AFTER replacing ignition parts?

[EPorsche]

If you have spark, that means fuel or air is the problem. Does your fuel pump run? What is you fuel pressure? Could you fuel filter be clogged? How low did you run the tank down lately? With CIS, was there a drop in winter? Just some questions to think about.

[roadhog]

It sounds like the control piston in the fuel distributor is stuck.The cold start valve is providing a charge of fuel at startup but then the fuel distributor should take over.Try removing the air filter and lifting the airflow sensor plate ,it should move with only slight resistance.If it is stuck there maybe some simple remedies but I will defer to some one with first hand experience for that.This happened to my 76 but it had set for years so I sent the distributor off to be rebuilt.

[grim77911S]

Full tank of gas, filled before I put it in the garage. Pop off valve and ignition parts were installed before it died in the garage and it ran GREAT.
Replaced fuel pump as a first place to start as it was noisy and was suspect of pressure drop due to age. After that, same as before, no start.
Lifting sensor plate makes the pump run and injectors pump up.

[roadhog]

Try holding down the throttle enough to cause the engine to run about 2000 RPM and start.If it will run at this speed then the injectors may need cleaned or replaced

[grim77911S]

Throttle seems to have little affect on the starting, it will idle then die even with the throttle in any position. If it were carbed it would probably do something, and unfortunately that is where most of my experience is. Learning the CIS by the seat of my pants so to speak, thanks for your help.

[T77911S]

when you lifted the sensor plate, was there more resistance with the pump running than when the pump was off?

does the gas pedal move the throttle plate?- all connections of linkage connected.

any vacuum lines off?- check the one to the dist. check the hoses to the aux air regulator.

check the rubber "boot" that connects the TB to the air flow sensor

check the hose that goes from the back of the "boot" to the oil tank and the one from the oil tank back to the rear of the engine.

is the oil cap on?

how about the cold start circuit?- power to the TTS? and CSV?

someone may know about this, but is there a screen in the gas tank that could be blocking the fuel line?

is the spark a STRONG spark?

try lifting the sensor ( just a little ) while someone starts it to dump extra fuel in there.

do you have a gage to check system pressure?

[Howard M]

Verify that the pop-off valve is sealed closed at the top and not leaking around the cement joint. Look for cracks with a bright light and a dental mirror. Double check all vacuum lines, especially at the point where they connect to a hard line. Wouldn't hurt to check the points condition and gap, too. All of the plug wires pushed home?

[ael911]

If it is a vacuum leak or stuck fuel plunger it should still run, but not well.
I think it could be contanminated fuel or bad fuel.

I had a small leak in the filler neck to the fuel tank. After washing the car, it would suddenly die while at idle. Then it would start and die after a few seconds, no matter the rpm. Sometimes it wouldn't fire up no matter how many times I turn the starter. Turns out a small drop of water got mixed into the fuel tank that would cut off the engine. I drained the tank and dumped several bottles of ISO Heet to evaporate the water. The car fired up and idled roughly until all the water was burned out of the system.

[afterburn 549]

filled with diesel ??

[grim77911S]

Throttle plate has increased resistance when lifted up.
Spark jumps at least a half an inch.
Filled with gas, not deisel.
Just bought a pressure tester gauge on Ebay.
No noticable vacuum leaks.
Seems to get gas at start, but not afterward.

[Steve Marshall]

Check your pop off valve.

[grim77911S]

Brand new valve, rubber o-ring perfectly seated, ran great when I parked it a month ago.
Something seems to have stuck or something while just sitting in the garage, creating the NO start condition.

[LakeCleElum]

Check WUR/cold start valve....That's was caused these sysmptons on my 73.5 CIS...

[Steve Marshall]

Have you looked at it recently? One good back fire and that thing will blow right out.

[grim77911S]

If you are speaking of the pop off valve, it is intact as installed prior to it not starting.

[dm36415]

I had a similar problem with my 77 CIS. Problem was the boot had somehow slipped up in back, causing a vacuum leak, hence the air flow sensor would not raise after starting and the car would die from fuel starvation.

You might try jumpering the relay to keep constant fuel flow while the key is on, which will eliminate the need for the sensor to be raised for the engine to continue running.

[jjrowe]

I just finished a rebuild on my 76 911S and had the same issue when I tried to start it back up. It would idle for a few seconds and then die. It turned out to be my points which really made no sense since there was spark some of the time. The gap setting was off just enough so that the spark got weak after a few seconds of idle. I think your 77 still has points so you might make sure your dwell is set correctly.

Jesse

[T77911S]

let us know what the system pressure is when you get the gauge.