Slow churning starter motors

[moggiegeek]

Hi, I've noticed that despite swapping fully charged batteries, gleaming connections and a choice of starter motors my moggie still continues to have periods of slow churning starter motor then a few seconds later a period of faster cranking speed.
What is going on here?? I began to wonder of the solenoid itself is at fault?
Of course all of this is worse in colder weather.
Help.

[Peted7202]

If you have a jump starter try it. What happens?

[geoberni]

I assume it's a Key start as you refer to the Solenoid.

Do you have a Multimeter?
If so, connect it across the main terminals, set at DC Volts, and it should read battery voltage.
Keep it connected like that and have someone turn the key.
It should drop to almost 0 volts.
If it drops to perhaps 2 volts, it would explain the slow start.
Keep it connected and if the motor, as you say, "a few seconds later a period of faster cranking", does the reading drop nearer Zero?
That would indicate the solenoid 'pulling in a bit more' after having power applied longer, therefore definitely the solenoid or it's operating connections.

If you don't have a meter, the rough and ready option would be to get a single jump lead from the Battery output (whichever polarity your car is) and touch it firmly to the lead the Starter side of the solenoid.
If it spins OK then the solenoid, OR the solenoid operating connections.
Just be aware of doing it this way, as there will be a bit of a spark as you connect it.

[oliver90owner]

IF it is not the battery, not the starter motor and all connections are very low resistance, it may be either an electrical or mechanical fault - the solenoid or starter ring gear.

Are these a regular cyclic occurrence or an occasional nuisance?

Personally, I would likely jam a shunt (as in an old, heavy screwdriver across the solenoid connections, although a jump lead to the starter motor might be better for most.

[paul 300358]

Is the ignition timing too far advanced?

[moggiegeek]

Thanks for the leads (haha), I'll certainly use jump start cable to test solenoid. It is a key operated solenoid with starter button. It does this both on key and button.
I'll check the timing though when it does start and run timing doesn't seem an issue.
Ill test as described across battery terminals with multimeter to see if solenoid pulls in a bit more current later in trying to start.
Report back when permafrost melts.

[philipkearney]

What condition is your earth strap in ? It's often overlooked. You can try it by putting a jump lead between the engine and the body and note any improvement. It's likely to be fine but often overlooked.

[mowogg]

I resolved a similar fault by changing all the HT leads and earth straps. I could not find anything wrong with the leads but they were all very old.