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-   -   SC Won't Start?? (http://forums.pelicanparts.com/porsche-911-technical-forum/962220-sc-wont-start.html)

vesnyder 07-04-2017 04:04 AM

SC Won't Start??
 
Yesterday I left the ignition in the "on" position and wore down the battery. Put a battery tender on the car over night and tried to start this morning and it just turned with no ignition. I usually starts on first turn so I knew immediately something was up. I did not hear the fuel pump so I thought it might be the fuel pump relay. I replaced the relay and the ignition switch started acting really weird - like turning over the engine before I turned the ignition all the way and making a very strange sound. Any ideas??

The ignition switch may be an entirely different issue but the pump relay replacement and the way it changed the switch start sequence was very odd.

vesnyder 07-04-2017 04:27 AM

Looking at the relay part numbers I replaced it with the wrong part # (911.615.109.01 vs 911.615.108.00).

arbita1 07-04-2017 04:56 AM

Are you sure the battery is fully charged? Is it an optima battery by any chance.


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vesnyder 07-04-2017 06:41 PM

No optima - I've already experienced that! The battery is charged enough to start it.

Any other ideas?

T77911S 07-05-2017 03:36 AM

what does charged enough to start it mean?

it can turn over but there may not be enough voltage to fire the CSV.

put a meter on the batt while cranking to check the voltage.

how old is the batt.

check fuse 18

vesnyder 07-05-2017 04:45 AM

My ignition switch is going bad and I am wondering if this would prevent the fuel pump from working? The car is getting no gas and before I dig into the pump I feel I should replace the key starter lock. Could this be the culprit?

theiceman 07-05-2017 05:18 AM

if its an SC you wont hear the fuel pump when the ignition is on ,only if you are cranking, or if you have the fuel pump relay jumpered .
if you can turn over a starter motor there is more than enough electricity for other things, by far the biggest draw on a battery is the starter motor.
I am wondering if you have cooked your CDI box by leaving the ignition on and you no longer hear the whine from it with ignition on that you normally would.

to validate you had no fuel pump did you turn on the ignition then go around back take the air filter out and lift the air plate ? or did you just not hear the sound you normally do when you have the ignition on .

If your ignition switch is wonky it could definitely be that its not providing power to cdi box also.

The old adage of troubleshooting .. always fix what you can see, before fixing what you cant see. .....fix the ignition switch first because you KNOW that's an issue

boyt911sc 07-05-2017 05:32 AM

Cdi...........
 
Quote:

Originally Posted by theiceman (Post 9650507)
if its an SC you wont hear the fuel pump when the ignition is on ,only if you are cranking, or if you have the fuel pump relay jumpered .
if you can turn over a starter motor there is more than enough electricity for other things, by far the biggest draw on a battery is the starter motor.
I am wondering if you have cooked your CDI box by leaving the ignition on and you no longer hear the whine from it with ignition on that you normally would.

to validate you had no fuel pump did you turn on the ignition then go around back take the air filter out and lift the air plate ? or did you just not hear the sound you normally do when you have the ignition on .

If your ignition switch is wonky it could definitely be that its not providing power to cdi box also.

The old adage of troubleshooting .. always fix what you can see, before fixing what you cant see. .....fix the ignition switch first because you KNOW that's an issue




You could leave the CDI running for hours hours and not worry about it. The CDI would outlast a fully charged battery until the battery is totally drained of power. Have you ever experienced or heard a CDI going bad because the ignition switch was left @ ON position? Keep us posted.

Tony

theiceman 07-05-2017 06:20 AM

Quote:

Originally Posted by boyt911sc (Post 9650514)
You could leave the CDI running for hours hours and not worry about it. The CDI would outlast a fully charged battery until the battery is totally drained of power. Have you ever experienced or heard a CDI going bad because the ignition switch was left @ ON position? Keep us posted.

Tony

Hi Tony I have heard of it but as always its third hand tribal knowledge . Ill see what I can find on the subject and post here if I find it.

Bob Kontak 07-05-2017 08:38 AM

Quote:

Originally Posted by theiceman (Post 9650507)
to validate you had no fuel pump did you turn on the ignition then go around back take the air filter out and lift the air plate ?

+1

Put this variable (unknown) to bed.

vesnyder 07-05-2017 09:27 AM

Ordered the ignition switch and will provide an update after I replace. In teh meantime, what are the fuses to jump to check the fuel pump? I saw something about jumping 87 to 16 (or something similar) but what do those numbers refer to? I saw a photo in my searches and cannot find it anymore.

T77911S 07-05-2017 09:42 AM

remove the connector on the top rear of the AFM and turn the key on, pump should run with engine off.
try to crank it.

vesnyder 07-05-2017 09:54 AM

Where do I find the AFM connector?

Bob Kontak 07-05-2017 10:05 AM

Quote:

Originally Posted by vesnyder (Post 9650841)
Where do I find the AFM connector?

Lift the air plate with the key on and advise. Listen for fuel pump.

Slow down a little.

AFM sensor is on the rear of the AFM. It's just below the black rubber bellows. It's kind of hard to get to but not impossible.

You jumper the relay holes, not fuses. Edit: I will get you the socket hole numbers if you try the lifting trick.:D

theiceman 07-05-2017 11:27 AM

Quote:

Originally Posted by Bob Kontak (Post 9650859)
Lift the air plate with the key on and advise. Listen for fuel pump.

Slow down a little.

AFM sensor is on the rear of the AFM. I't just below the black rubber bellows. It's kind of hard to get to but nut impossible.

You jumper the relay holes, not fuses.

do as above , you can check in literally 30 seconds, no running around looking for jumpers and sensors.

Bob Kontak 07-05-2017 11:45 AM

Quote:

Originally Posted by theiceman (Post 9650952)
no running around looking for jumpers and sensors.

Those Ohio dudes just don't listen.

I bet the electronic part of the ignition switch is tits up, in the ditch.

theiceman 07-05-2017 11:55 AM

Quote:

Originally Posted by Bob Kontak (Post 9650970)
Those Ohio dudes just don't listen.

I bet the electronic part of the ignition switch is tits up, in the ditch.

yup ,

vesnyder 07-06-2017 04:17 AM

I lifted the air plate inside the air filter box and it made a sound - could be the fuel pump, except it was making more noise than I would expect from a fuel pump. What does that tell me?

theiceman 07-06-2017 05:01 AM

That is the fuel pump and it sounds like it's working fine. Your issue is not the fuel pump i would think. .

Do you have a high pitched whine from the back of the car with the ignition on!? If not I'm thinking your cdi is shot or no power to it.

Maybe your ignition switch is not powering it

Check to see if you have Bosch cdi or permatune

Pull the main lead off the distributor and lie it close to a piece of metal and have a helper turn it over. See if you have spark.

vesnyder 07-06-2017 05:50 AM

I have the Bosch CDI and I do hear the high pitched whine with the ignition on. Checking on the spark ...


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