Non starter - please help

[Notay]

Hi my friend has a 1971 911 which was fitted with a 911SC (3.0litre) engine when it was bought.

the starter motor does not seem to engage and turn when the ignition switch is turned. There is a buzzing noise coming from the CDS unit so I that works.

I have a funny feeling that there is no power being sent to the starter since the orange battery light on the dash does not come on when the key is turned but the red oil pressure light does. The battery has been charged and is reading 12.6V across the posts. Even if I add a jump start unit to the battery the starter still does not engage and the orange light on the dash does not come on.

To add more problems, the car has been sat for 3 years without use in storage. I have cleaned up the electrical contacts are goround points for the ignition system (coil, distributor, HT leads etc) - but still the started does not crank the engine over.
I am not sure if this is a starter, battery, CDS or ignition switch problem - please help. Are there any checks I am missing? Many thanks.

[Targalid]

You can check the starter function by placing a battery on the ground next to it and running jumper cables directly to it from the battery. You need to jack up the rear of the car to do this easily. While you are under there, check the ground strap which connects the motor to the car body, just forward of the transmission. It is big, nearly an inch across, woven copper. You can't miss it. Clean the connections at each end and reconnect. That may be your problem. Also check the car battery ground in the same way, disconnect the ground strap, clean the connections and reconnect. Good luck.

[T77911S]

thas a lot of work, ^^^, i have a push button switch with 2 wires and alligator clips i can clip on the start terminal of the solenoid and the battery cable at the starter to test it. a screw driver across the 2 terminals will work too, make sure it is NOT in gear.

while you are under there you might as well check for power, 12v, on the yellow wire to the starter, who knows, you may get lucky and it is just not connected.

+1 on the ground strap.

make sure the bulb is not burned out.

[Notay]

Hi Many thanks for your replys. I have not yet managed to test the stater but still trying to understand the starter system since I have never done work on this before.

From underneth the car I can see the large battery cable which has the a rubber dust cover and I can also see two yellow cables connected to the solenoid. I am guessing one of them is for the alternator - what is the other one for and how can you distinguish between the two?

Also which one would be the start terminal of the solenoid - again one of the yellow wires? Many thanks.

[Flat6pac]

If youre using the 3.0 starter, you need the yellow wire to the top connection and the yellow/blue stripe to the visable lower tab connection. visa-versa, starter doesnt work.
Bruce

[Notay]

Hi - cleaned earth strap connections on engine and near the battery post today. Also managed to get the starter to turn by adding a wire to the ignition terminal and touching the +ve battery post - so I am glad the starter is okay.

However when taking a voltage meter to the ignition trigger for the starter solenoid (yellow wire) and when the key is turned - I only get 0.2V at the terminal and not +12V as expected - leading me to believe the ignition switch is at fault. Does anyone have any tips on removing the ignition switch barrel for inspection?

Also what is the yellow/blue wire on the starter solenoid for?

Many thanks.

[T77911S]

you dont have a car alram do you?

[Notay]

Hi there is an aftermarket alarm fitted to the car but according to the owner before it was put in storage it was not working and was not being used. Do you think this could be the cause of the low voltage at the ignition trigger?

Where would I start to remove the car alarm?