V12 Not Starting - Starter Dead.

[SESH]

Just got my series 3 back on the road after a full body re-build. I have an intermittant problem. The starter motor will not turn and no clicks from the relay. It's an Auto so tried moving the gear selector but still nothing. Then after about an hour it starts! Could it be a sticky micro switch on the gear selector, a faulty relay or is the Starter Motor on the way out? By the way the battery is fully charged and I earthed the engine to the negative terminal so its not the earth strap. Any ideas?
Cheers
Mike

[christopher storey]

Mike : Have you tried detaching the small solenoid lead ( probably red/white ) and putting a voltmeter on it when the starter switch is operated ? If you are getting 12v to it, then it points to a starter/solenoid fault, possibly a loose lead to those large copper nuts . If, however, you get no volts, then it points to a fault upstream, either the inhibitor switch or possibly the starter switch itself. On my S2, which I think has the same switch on the steering column I had to replace the switch because of faulty contacts which I could usually temporarliy cure by shaking the wires coming out of the back!

[SESH]

It seems to be intermittant. Not sure if it coincides with the high temperature when the engine has been running a while. But when trying to re-start it doesn't do anything and no clicks from the relay. But after a while (an hour or more) it starts. Plus I have taken the red/white wire off the relay and shorted it straight to the positive pole on the battery and it starts. I am hoping it's just a micro switch on the auto selector/inhibitor switch. I will check the volts to the solenoid wire. Is it possible that the starter motor will be breaking down on getting hot from heat generated in the engine bay?
Cheers
Mike

[andrewh]

I had exactly the same problem on my 73 XJ12 auto. It wasa misalignment of the inhibitor switch on the gear quadrant for what its worth. Good luck

[christopher storey]

Mike : if your test on the red/white lead was at a time when it would not otherwise start, it shows that both solenoid and starter are ok , and as Andrew has said, the likely culprit is the inhibitor switch , although the starter switch itself cannot be ruled out

[SESH]

Hi Guys,
Thanks for the responses.
I went to a classic car show today and the starter behaved faultlessly. Although it has a tuning problem, I think it is running very rich. Very strong smell of petrol and is holding back at low RPM when going round roundabouts or tight corners. It is definately a fuel problem. Maybe the floats need re-setting or there is a fuel pick up problem, although tank was half full. But sounds like two seperate tuning problems. I have only just got the car back on the road so I am expecting a few teething problems after a long lay up and previous owner only did 2,000 miles in 10 years!!
Thanks again I appreciate your advice.
Mike