Help - Just wouldn't start

[RTH]

I've been driving my new "old" dream car for about a month... It always fired right up, ran great, drove great, looked great.... Did I mention its a great car....? I drove it about 30 miles today parked and went to a meeting, when I came out It would not start. Cranks fine, but no hint of firing. I checks all the fuses, Its got spark at the coil. Any ideas ???? I've read thu a number of the threads, but could not find one with this symptom.

It's a 1979 911sc

[dbanazek]

My guess is warm up regulator.

[Lorenfb]

Since you have spark (1" jump), move the sensor plate and see if the
fuel pump runs (you'll hear fuel in the lines). Next make sure that the
spark is getting to each plug. I've seen where moisture gets in the cap and
causes problems and between the black shield and the red dist. cap.

Check for fuel on the plugs. The 911SC is very easy to get started.
The problems arise after it starts and getting it to run great which is
still simple compared to other Porsches. Can't find a more reliable
Porsche than a SC.

Good Luck
Loren
'88 3.2

[Rich Lambert]

Fuel pump relay?

[Mike Kast]

Now wait a second, don't throw a million potential problems at the poor guy!...I had a very similar problem and if you did searches you have probably seen my name come up. Is this your first 911? Before you start changing parts you have to get some diagnostic info. And honestly I'm not competent at diagnostics. If your not either it might pay to let a pro look at it. It may save you a lot of headaches.
Do some of the tests that Lorenfb mentioned definitely check for fuel and this will piss you off, gas in the tank, I'm betting you have gas, but it is a needle someone has to stick in you Do you have any books? Get some. whether you get it running yourself or not this time.
Every problem you have with this car will be a learning experience and if you stick with it long enough you will know the car really well someday. It's worth it to me. sticking with it I mean. as frustrating as it might be sometimes.

[sammyg2]

If the engine has good spark and the correct fuel/air mixture it will start.

If you had good spark we can prolly rule that out.
Now to make sure you have the correct air/fuel mixture you first need to make sure the fuel pump runs when it is supposed to. That means when the engine is cranking or when the ignition is on and the air flow sensor plate is lifted off it's resting place.

Question:
How long did the car sit while you were in the meeting?
These things are famous for warm (or hot) starting problems if the fuel injection fails to maintain proper pressure to the fuel injectors when the engine is shut off. This prevents the fuel in the injector lines from boiling and causing vapor lock.
The check valve on the fuel pump and the fuel pressure accumulator are supposed to maintain the pressure long enough for the engine and fuel lines to cool down. If either one is malfunctioning this could be your problem. if the engine sat for more that an hour before you tried to restart it, this is prolly not your problem and you need to look elsewhere, the fuel pump or power to the fuel pump would be the first suspect on my list. First check the fuse, then the relay, then finally the pump itself.

If it is a warm start problem the temporary fix is to pull the air cleaner cover and filter and with the ignition on, lift the air flow sensor plate a little until you hear the injectors fire. Do this for a couple of seconds and then start the engine.
That will hopefully bleed the vapors from the injector lines and prime the engine and will get it started. Then as soon as possible replace the check valve or accumulator or both.

[Par911]

It could be electrical. I had the same problem and it turned out to be an electrical problem. I agree with Dr. Sam, I would look at the fuse box and make sure there is no corrosion in the wiring. Also as Rich said a new relay might be what you need. Do you hear the fuel pump when you turn the key in position 1?

[vash]

you gotta start at the basics. do you have spark at the plugs? are you getting fuel?

[RTH]

Thanks for all your input... I had a chance to look further this morning and found that there is no spark at the plugs... There is spark at he coil, but it does not jump 1" only about 1/16"... seems weak..... I've verified that there is gas flow....

[ruf-porsche]

Do you hear the CDI whinning when the key is turn to the run or start position? If not bad CDI.

[Mike Kast]

does the CDI go bad when the coil dies and send crazy voltage everywhere?

[ruf-porsche]

Sometime

[vash]

i always look for spark at the plugs, if it is weak or not even there, i move up stream. at the coil, yes? then maybe your rotor or cap is wasted.

[RTH]

I've checked the Cap and Roter they seem fine.. The CDI does Whine....
Can the Coil still provide spark, but be weak or could it be a grounding problem????

[Lorenfb]

If the spark at the coil jumps about 1", then pull a plug and see
that the spark is good (1/2') at the plugs. Check for fuel on the
plugs.

All the above posts by many should provide the proper direction
to get the car started.

[ruf-porsche]

If you have an ohm meter I would at least measure the ohm of the high tension wire between the cap and coil.

[RTH]

There is spark at he coil, but it does not jump 1" only about 1/16"... seems weak..... I've verified that there is gas flow....