Starter Motor - DIY, How to diagnose and repair/replace a starter motor fault. Options

[youseman]

After buying my new celica and charging the battery (hadn't been driven for months) I discovered that it wouldn't start every time. That is to say that the engine did not turn over but would start fine with a bump. There was also a clicking from the engine bay when the key was turned to start.

I had a few things in mind so went about them in the cheapest order.

(The starter motor is located on the bulkhead side of the engine block by the bell housing.

1. Checked all the fuses and relays with a multimeter and 12v powersource.
I found no problems so I left these but change these is there are any problems then try again.

2. Continuity checked the starter wires in my wiring loom from battery to ignition to starter motor.
Again, no problems.

3. I removed the starter motor for some bench testing. I connected my battery to the correct terminal, negative to the case (case is ground) and another positive wire from the positive battery terminal to the control wire input. The solenoid click but the motor would not turn. I then stripped the thing down, taking care not to loose the roller bearings inside (they will try and escape). I discovered the solenoid contacts to be coated in copper dust and very discoloured. I cleaned the solenoid with Wynn's carb cleaner and used some p800 grit sand paper to clean the contacts. I also continuity checked the rest of the starter motor including the coils.

After reassembling and reinstalling... Hey presto! It works perfectly.

If the is no continuity within the motor coils you will need to replace the whole thing unless you are experienced with motors.

I will add pictures when I next do some engine work as it is not easy to get at.