911 problems

[alloy562002]

I have a 1980 Porsche 911. I have been having problems every once in
a while...I am not able to start the car. It turns over but won't
fire. I get out and unplug the CDI unit and then plug it back in and
then it starts. I've had the CDI unit looked at by an electronics guy
and it's ok. Also I've noticed that my coil isn't consistant.
Sometimes it's cold and sometimes it warm. This is a new coil and a
new coil distributor cable. Have checked all ground connections and
cleaned the ends of any corrosion. Taken the plug from the ignition
switch out to check for oxidation.
So.........any suggestions would be appreciated.

thanks

[RoninLB]

Originally posted by alloy562002
I have a 1980 Porsche 911.I get out and unplug the CDI unit and then plug it back in and
then it starts. I've had the CDI unit looked at by an electronics guy
and it's ok.

What mfg of CDI

[alloy562002]

It's a Bosch

[emcon5]

The times it doesn't start, can you hear the CDI box whine?

If so, instead of plugging and unplugging it, try wiggling the green wire that runs to the distributor.

Tom

[jb73911T]

If you have the push on connector at the coil you might check and make sure the connectors have not lost their "crimp".

[alloy562002]

Replaced the fuel pump relay. It has started every time since. I have a question.
Are you supposed to hear the fuel pump run every time you turn key to "on"?

[Chuck Moreland]

Yes

[Early_S_Man]

No -- SC's have an airflow switch in the fuel pump circuit that is not closed until airflow is caused by the engine turning over. A special set of contacts inside the starter solenoid provides initial power to the fuel pump ... but, only while the starter is operating.

[alloy562002]

Just an update. Put in the new fuel pump relay and the car is running excellent so far.

[ChrisBennet]

Originally posted by alloy562002
Just an update. Put in the new fuel pump relay and the car is running excellent so far.

One down, 910 problems to go...

[RoninLB]

Originally posted by alloy562002
Just an update. Put in the new fuel pump relay and the car is running excellent so far.

so without pulling out the books.. your CDI plug affects the fuel pump relay?? news to me.......Ron

[alloy562002]

dont know if they are connected in any way just tried the relay seems to run anyways for now!!!!! as far as moving wires maybe could have been a fluke on time

[alloy562002]

Well......the car wouldn't start again. It also stalled while I was at a stop light. So, the first time I did what I normally do.......wiggle the wires to the CDI unit, tried to start it...no go, then I removed the CDI unit, tried to start it, again no go, at this point I was very frustrated because normally it would have started after doing all that. Then I decided to tap on the top of the fuel filter while it was being started and it started. WTF?

[alloy562002]

Quick note...I remove and replace the CDI unit....then try to start it.

[john walker's workshop]

get a loaner CD unit. just hang it on the plug and drive around for awhile. also check the green wire for fraying, right where it connects to the distributor body.

[Kevin Stewart]

I had the same problem, when it stalls all the light dont come on, turn key off turn key on lights come on. car starts, My problem was the plug was corroded, i also took a scribe and tigthten up the female connections inside the plug. Wide body i believe had a simular problem, except his wires had corroded several inches away from the plug, Kevin

[Thomas Owen]

I am with Warren on this one. The fuel pump should not run when the key is on except if the air flow switch is disconnected. In that case it will run as soon as the key is switched on (at least that is what my '78 did).
Check and recheck all your connections!
Good luck,