starter wont stop starting :)

R

restojon

New Member
Hi all,
I'm in the process of recommissioning my 2000SC and I've had a strange fault occur with the starter motor, when I turn the key to engage the starter motor the starter turns the engine but when I turn the key off the starter motor continues turning. I pulled the starter motor and cleaned everything and bench tested it and everything works as it should. When refitted and connected the exact same thing happened, I connected the battery up to the starter directly and the fault is still there but every now and then the engine will fire up and the solenoid disengages and the next few times the starter works fine. This is whether the battery is connected normally or wired directly. I've noticed that the alternator is not charging the battery and wondered if this could be shorting something out? Any help appreciated.
Jon. :D
 
Do you have the inertia type starter or the pre-engaged? My feeling is that it could be a sticking solenoid or an ignition switch problem. If it is the pre-engaged type, you should be able to dismantle the solenoid (to a degree) and clean up the plunger and bore. If it has a bit of rust or muck in it it will cause this.
Also try disconnecting the trigger wire from the starter and jump it with a screwdriver or bit of wire, this will eliminate the ignition switch from the equation.
 
*It's an inertia type* SEE CORRECTION BELOW. I've cleaned the solenoid out very thoroughly and bridged the solenoid terms and it still does the fault then too. Problem is that as I'm carrying out any tests to find the root of the problem just as I start to get somewhere the thing starts working normally and I can't get it to replicate the fault.
 
restojon said:
It's an inertia type. I've cleaned the solenoid out very thoroughly and bridged the solenoid terms and it still does the fault then too. Problem is that as I'm carrying out any tests to find the root of the problem just as I start to get somewhere the thing starts working normally and I can't get it to replicate the fault.
Click to expand...

Are you sure it's an inertia type? I'm assuming the car in question is the 72 2000SC mentioned in your 'signature'. Our 72 2000 Auto had a pre-engaged.

Were inertia starters still being fitted to 72 cars?

The other thing which puzzles me is you say that you've connected the motor directly to the battery. Don't inertia starters only have 1 terminal on their bodies, and so connecting that straight to the battery will cause it to keep turning?

Just my thoughts on the matter: - the ignition switch "start" position on our 1972 car didn't go straight to the solenoid "command" terminal. It went to a solenoid control relay which was on the passenger side under the bonnet. This relay, when energised (i.e. the ignition switch turned to 'start'), closed contacts between a 12v supply and the solenoid "command" terminal.



I'm wondering, assuming your car is wired the same way ours was (not a safe bet in most cases with P6's though!!), if what's happening on yours is that the relay is sticking and so keeping the command terminal energised.

The other thing I'm wondering (but I'm not sure this would actually cause the problem we have here) is this: - assuming it's got a ballasted coil, has the solenoid command wire and the ballast bypass wire (the wire which goes from the solenoid to the coil to give it 12v during starting) been mixed up?
 
APOLOGIES. BRAIN FAILURE MOMENT. :oops: :oops: :oops:

Not an inertia motor, you're absolutely right there. Been a long day I'm afraid, guess that's what happens when you work on pre war cars all week and work on your own classics on the weekend.

I do have the relay on the inner wing and it's clicking in and out which suggests it's doing it's job, when disconnected from the starter it functions correctly and when you wire up the motor independently of this circuit the fault is the same. However to be sure I'd have to put the meter across the relay to check.

The starter wires you mention are different sized terminals on my car so shouldn't be able to mix them up short of using a hammer to fit one of them.
I wondered if the alternator possibly having a short inside it somewhere is giving the solenoid another feed? It would stand to reason I think but am not entirely sure.
 
restojon said:
APOLOGIES. BRAIN FAILURE MOMENT. :oops: :oops: :oops:

Not an inertia motor, you're absolutely right there. Been a long day I'm afraid, guess that's what happens when you work on pre war cars all week and work on your own classics on the weekend.

I do have the relay on the inner wing and it's clicking in and out which suggests it's doing it's job, when disconnected from the starter it functions correctly and when you wire up the motor independently of this circuit the fault is the same. However to be sure I'd have to put the meter across the relay to check.

The starter wires you mention are different sized terminals on my car so shouldn't be able to mix them up short of using a hammer to fit one of them.
I wondered if the alternator possibly having a short inside it somewhere is giving the solenoid another feed? It would stand to reason I think but am not entirely sure.
Click to expand...

We've all had brain failure moments, I've had them more often than not! :p

I had a feeling the ballast bypass terminal was different in size to the command terminal. That's been ruled out, then.

The alternator main charge lead connects to the top-most terminal stud on the solenoid, if I recall. That being because also connected to that same top-most terminal stud is the main +ve cable from the battery. In short (bad pun!!), the solenoid top-most terminal stud is being used as a "junction/node" to connect the charge lead from the alternator to the main +ve battery cable.

If there's a fault in the alternator, I doubt that would cause the starter to keep running... assuming the wires have not been wrongly connected; something else has crossed my mind as I write this.

You say the alternator doesn't charge, right? Is the ignition light staying on?

You haven't connected the battery charge wire from the alternator to the wrong terminal stud on the solenoid, have you? What might account for the problem you have is that when the engine is started, the alternator is producing an output, it's feeding into the wrong terminal stud (the stud that carries current into the starter body), so it's keeping the starter running instead of feeding the battery.
 
Thanks for the reply. I see what you're getting at. I've got all of the wires you mention on the upper terminal, I did look incase anything had moved and was arcing onto the other terminal but that doesn't appear to be the case. The alternator light is being erratic, sometimes it doesn't come on with the ignition, sometimes it does, sometimes it's on but dim. When it does come on whether normal or dim it goes out when the engine starts though.
 
restojon said:
Thanks for the reply. I see what you're getting at. I've got all of the wires you mention on the upper terminal, I did look incase anything had moved and was arcing onto the other terminal but that doesn't appear to be the case. The alternator light is being erratic, sometimes it doesn't come on with the ignition, sometimes it does, sometimes it's on but dim. When it does come on whether normal or dim it goes out when the engine starts though.
Click to expand...

Hmm... thinking cap time!
 
SPECULATION TIME WITH ADDED THINKING THROWN IN:

I've noticed the alternator belt was loose and is now slipping fairly bad ( needs a new one, time for shed raiding) the alternator light is working again now but the battery isn't charging well. When the battery get's to a certain stage of flatness the starter begins to misbehave, could the solenoid not be energising completely and in turn not disengaging?
:?:
 
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