SC won`t start. It`s Electrical.

Aurel · Aurel's Garage

At the beginning, it felt like a very weak battery: the engine would crank one turn, and then stop turning. I recharged the battery, I tried to jump-start it. Same thing. Now, the starter won`t turn at all, and when I attempt to start the motor, all the electricals will die. Even with a charger connected to the battery. I have to reset it by disconecting-reconnecting the battery.
So far, I have:
- Checked the connections to the battery (untightened, cleaned, retightnened)
- Checked the connections to the starter
- Checked the ground strap.

All look ok. What should I test next ?
It looks like a short occurs when I try to start the car. Could the starter cause that ? The car is a 78 with 105,000 miles, and the starter is original. Thanks for any clues.

Aurel

speedy · 12-27-2003, 08:25 AM

hi aurel, fist you have to be sure its electrical! do you have a volt meter? first I would check the batt and make sure its holding 12 volts then you should check the volts when cranking. have someone start or at least try and start it while checking for a volt drop at the batt. If that seems ok then check the volts at the starter. if all of that seems good then pull ut the trusty persuder (hammer) and tap the starter while someone cranks it. try theses things and if that doesn't work then email me back and I will give some info on how to easily check for a short......good luck

Early_S_Man · 12-27-2003, 08:29 AM

Aurel,

Does your car have the factory alarm system?

If so, it sounds precisely like a classic case of the car being disabled by a failed alarm module!

Check the following thread for details ...

'82 SC Won't run

Aurel · Aurel's Garage

Warren,

My car does not seem to have an alarm system. Just a fake keypad that is connected to nothing...I feel like removing the starter to check it out, athough this looks like it is going to be a pain...

Aurel

Aurel · Aurel's Garage

Speedy, I wish I had borrowed for the week-end that voltmeter I have at work...I will get a new one and check the voltage at the starter. First thing to do. Thanks.

Aurel

Early_S_Man · 12-27-2003, 11:31 AM

Aurel,

The factory alarm system has a keyswitch in the driver's door locking/latch area.

If you don't have the factory alarm, your problem sounds battery-related, and ultimately may be alternator-related if the car has been driven regularly, lately. Many of the CDI systems and starter solenoids don't work when attempting to start with battery Voltage below 11.0 Volts! My assumption was that a surge that ocurred while attempting to start fried the alarm unit, but the battery may have just depleted energy to the point it is now below the operating threshhold for the ignition and starter solenoid.

Aurel · Aurel's Garage

I have checked the battery voltage, it reads 12.5 Volts. Seems fine. I have measured voltages at the starter solenoid: the big black wire is always at 12.5 Volts vs ground. Normal since it seems direclty connected to the battery. The yellow wire has shown no voltage at all, even when turning the key to start. This seems to be the problem. What is to the other end of the yellow wire ?

Aurel

ruf-porsche · ruf-porsche's Garage

Could be a bad ignition switch. If you know how to attach a remote starter to the starter solenoid and turn the key to the run (not start position) you should be able to start the engine with the remote starter.

Aurel · Aurel's Garage

It could very well be the igntion switch. I will try the remote starter. If I connect a switch between the yellow wire and the black wire on the solenoid, and turn it on, the engine should turn, right ? (Just checking before destroying my starter...)

Aurel

Por_sha911 · Por_sha911's Garage

Does the battery hold a charge? I've seen a short in the battery mess everything up. Check the solinoid. Also, I didn't think the factory alarm killed the ignition (sorry for the small hijack).

autobonrun · autobonrun's Garage

when you check the voltage from the starter to ground, make sure the ground used to check the voltage is the same point the starter negative is grounded to. A corroded return from the starter would not be detected if you simply placed the negative of the VOM on the closest ground point.

Early_S_Man · 09:17 PM

Aurel,

The yellow #50 wire comes from the ignition switch, but it goes through two connectors ... including the 14-pin connector at the relay/fuse/CDI panel.

RoninLB · 12-27-2003, 11:15 PM

Quote:

Originally posted by Early_S_Man
Aurel,

The yellow #50 wire comes from the ignition switch, but it goes through two connectors ... including the 14-pin connector at the relay/fuse/CDI panel.

and usually the aftermarket starter kill solenoid has smaller gauge wire than the yellow #50.
and the solenoid probably created 2 lousy connections, as it's inserted into the factory #50 connector in the luggage comp.

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by Aurel
It could very well be the igntion switch. I will try the remote starter. If I connect a switch between the yellow wire and the black wire on the solenoid, and turn it on, the engine should turn, right ? (Just checking before destroying my starter...)

Aurel

If you plan on using a switch you need to get a momentary contact switch (Similar to a door bell switch) Once the engine starts the start circuit with the switch must be off or else you will ruin the starter.

Yes connecting the black wire and yellow wire is the way to jump the solenoid.

Aurel · Aurel's Garage

Okay, i got the remote switch. This morning
I unplugged the yellow wire on the solenoid and connected the switch instead, and the other terminal to the thick black wire. Nothing happened. The voltage at the black wire was 11.7 volts. Maybe too low. So I tried the same with a battery charger connected to the battery (13.7 volts). Still nothing. And with the battery charger on the start position (15 volts). Norhing. It looks like I will be hugging my tranny soon...

Aurel

Aurel · Aurel's Garage

Stupid me...

I removed the starter, tested it on the bench. Both motor and solenoid are fine...I had used the wrong yellow wire to energize it in the car...back to square one.

Aurel

speedy · 12-28-2003, 08:59 AM

ok so now you know the starter works.....go back to the batt and check it with a volt meter while turning it over. if the volts have a drastic drop (should not drop more than 1 volt) then you know your batt is shot.
seeing that these are correct.....
1. batt holds 12 volts
2. batt doen't drop during cranking
3. starter works and is wired correctly
then you should jump the started directly (remote) and that should work. if it does then your problem is in the ignition switch or bad wiring. make sure you check the grounds on starter and batt this is very important. (common cause for most bad electrical)
hope this is helping?

Aurel · Aurel's Garage

Thanks speeder.
However, I still have some doubts about the starter motor: with 15 V and 55A directly connected to it on the bench, it was spinning very very slowly. Is that normal ?

Aurel

Doug Zielke · 12-28-2003, 11:02 AM

Quote:

Originally posted by Aurel
Thanks speeder.
However, I still have some doubts about the starter motor: with 15 V and 55A directly connected to it on the bench, it was spinning very very slowly. Is that normal ?

Aurel

No.
Take it to an auto-electric shop, and have it tested.

speedy · 12-28-2003, 06:16 PM

ok here is the funny thing....I was working on my car today and no &^%$ the same thing is happening to me. my starter would crank a couple of times then nothing. I jumped it with a batt charger it turned alot faster but didn't start! now when I turn on my ignition my power dies.
like I told aurel....check the batt! I put the voltmeter on the batt and turned it over and my volts dropped to about 3.2 volts. this is my problem....now I am not sure why but I will find out! anyone got any ideas?
I find it a little strange that I replied to this post and now I am having the same problem...