Aaaarg: Tech question: starter motor.

[Aerodynamica]

I need to broaden my starter problem query!

Basically, a week back on Thursday it wouldn't start. It would crank over a couple of times then you'd hear the starter pinion miss the ring gear and go "wheeeeeeee" It seems to grind on the ring gear too.

No I knew there was a bad patch on the ring gear but this was bodged good by disconnection the torque convertor, rotating it and reattaching it 4 years ago and it has been perfect ever since.

Anyway (skip to the end) I spent most of the freezing weekend removing the motor, adjusting the pinion, checking the pinion teeth, cleaning up the connections and refitting. As for the ring gear: all but one 10DEG area is fine but I adjusted the pinion so that it now comes out further to mesh in the gear more fully. Initially it worked a treat! I thought I'd sorted it for Monday morning.

Here's what I wrote on Autoshite.com about today's nightmare.

[size=x-small]I just spent all of Sunday and a bit of Saturday removing and examining the starter. The ring gear though bad seems like it could be 'cleaned up' with a file to clear the burrs on every tooth. And to deal with the bald bit of the ring gear (turns out it's in ONE place not two) I adjusted the starter pinion so that it went out further than it had and further than the right setting. All cleaned up and checked on the bench with a spare battery and refitted in the car first checking that the new pinion was not gonna fowl on the ring gear and that it didn't go too far or get stuck or anything.
I spent a LONG TIME on Sunday cleaning up the starter teeth as it seems that it's been grinding on all of them at any part of the ring gear like the motor spins before it's meshed.

So after all that it was up and ready to go and it performed brilliantly, nice strong and quite quiet cranking and the thing fired up and ran after a week.
Heated it up and cleared the 6" of snow off the top and all seemed good - went for a spin, came back switched off, tried the starter again, perfect: instant start. Decided to give it a better test. Switched off the LPG and cranked over so that it would not start to give the starter a full run of the ring gear several times over - not a hint of a problem. Fuel on again and cranked over nicely and fired up.

Left it several hours and tried again and it was fine.

I'd fixed it!

Err, it seems not. This morning it was back to its old tricks although it spun strong and fast (new 75Ah batt mind) it was yet again back to the crank twice then grind feature. I just don't get it. The only thing I can think of is that the severe cold is doing something to the solenoid as it was not quite as cold yesterday afternoon when it worked a treat. I reckon the thing engages fine and meshes in the gear initially, cranks a bit but then the pinion starts to slip back. Why would that be?? [/size]

HEEEEEEEEEELP!!!!

Dire straights now guys - I need more wisdom!!!!! What's causing the solenoid to 'pull back' after only 2 cranks and how does the motor still spin with the solenoid only partly out? Thought the motor only started after the solenoid was fully out??

[Aerodynamica]

Err, sorry it's on a CX

[DavidRutherford]

There's a fairly good chance that the starter one-way clutch is failing, and what is actually happening is that the starter pinion is still fully engaged, but the clutch is slipping and grinding a bit. I've had that happen before, although it has to be said that usually when that happens the clutch fails completely, meaning the starter is spinning at maximum speed with the pinion stationary.

[DavidRutherford]

And yes, I will fix CXC as soon as I can...

[Aerodynamica]

Hi David, where is this clutch device located and what does it do? I'm imagining it as a sort of 'free wheel' thing like on a bicycle hub.

Anyway, it's definitely disengaging while the motor still spins as you can watch it do this by activating the starter via the contact at the battery. The engine churns over 2 starter revs then stops with a Wheeeee!" noise. The ring gear shows that the entire thing has been getting chewed on the whole edge of the ring gear as though the pinion was only just catching it and no more.

It does occasionally get stuck and not disengage on days where it will start but only remains caught this way for half a second once in every 5 starts.

I really feel it's the solenoid not holding it engaged long enough but what I can't understand is why does the motor still spin if the solenoid is not fully 'out'? surely the contacts in the solenoid to activate the motor would disconnect if the solenoid had jumped a bit back from fully engaged.

Maybe the contacts are spring loaded and hence engage a little before the pinion does?

[Aerodynamica]

It is working perfectly again without even lifting the snow-covered bonnet.

Coldness-related problem fo' sho' so will be armed with a hair dryer and an extension cord in the morning

Also have bar and hammer ready to give taps to the solenoid and starter body - hadn't thought of trying that until now