Tech question: starter motor.

[j-j]

Hi amigos, I've been suffering some winter woes with the shite CX. The starter has some issues. With a fully charged battery and having the car running fine on Saturday afternoon it resolutely refuses to crank strongly in the cold of the morning. It now will not properly crank as of Sunday morning. I stopped and restarted it in Sat arvo many times to check its workings and it cranked over strongly without a hint if weakness and roughness.

 

The starter ring gear is badly worn in 2 places 180Ëš apart and about 4 years ago this was bodged shite style by removing the torque convertor drive plate bolts, rotating the TC and hence the ring gear by 90Ëš and reattaching the bolts in this new position so that the starter tended to act on the unworn bits of the gear. This worked fine for 4 years until last Thursday morning when it cranked twice weakly and then ground away at the worn bald bits of the ring gear.

 

Although the ring gear is crap, it has been working fine all this time but now suddenly doesn't.

 

The battery is good (brand new 5year warranty Bosch with 75 Ah)

Starter spins strongly but only manages 2 cranks before going "wheeee"! due to meeting a rough bald bit of the starter ring gear. Now seems to be every time tried as opposed to just meeting the bald bits 180Ëš apart.

 

When I get the oppo, I'll examine the ring gear and remove the starter for clean up and possible adjustment but until then does anyone have any ideas?

 

It's fairly clear to me that the starter pinion isn't going out enough to fully mesh into the crappy old ring gear but why would this suddenly happen? Also how would a maladjusted solenoid allow the starter to spin without the solenoid being fully engaged first?

 

Any leads greatly received!

[M'coli]

Is the starter inertia engagement? Then it'll be the cold sticking it to the shaft and not allowing it to engage properly - the solution is to take it off and clean and lube it.

[autofive]

...or the dodgy spots on the ring gear have seriously damaged the starter teeth

[j-j]

Thanks guys, I'm not certain if it's an inertia engagement. It's your bog standard solenoid with a fork that throws over the pinion and then the motor spins once the solenoid contacts are made.

 

It's coming off tomorrow evening for cleaning, lube and any adjustment to the pinion. Hopefully the pinion is not chewed to fakk.

 

Is there anything about the solenoid that can, now bear with me here, go 'half' wrong? I mean is there a 'pull in' power to it AND a 'hold in' power to the solenoid that are separate (i.e. if the latter didn't work right it would send the pinion over but soon it would run slack and less engaged) I only ask because the Haynes book talks about the 'pull in' resistance and the 'hold' resistance suggesting 2 windings to the solenoid.

 

As you can see, I'm not too clued up with starters!

[Rusty Pelican]

Solenoids normally either work or dont work , basically a sprung loaded piston inside an electromagnet , make sure piston isnt sticking in the magnet part , solenoid operates throwing the pinion forward as you say , starter then spins up , Just a note , dont operate the starter too much " off load " ie. off the car , these things are geared and often these gears are plastic , off load the starter can spin too quickly busting up the gears .

[CreepingJesus]

I've seen random problems with the solenoid end of a starter, caused by the black carbon clag from the brushes. Don't know if that helps any, but the dust will get everywhere, settle, and solidify. Like M'Coli says, a strip and clean won't go amiss.

And a new ring gear. Altho', I'd be tempted to spin the crank a few degrees, with a socket and bar to the bottom pulley, if the starter pinion's on a 'bald spot' again.

[j-j]

Thanks folks - basic overhaul needed then.

 

As for the dreaded ring gear, where the hell do you get one? And this CX being a semi automatic, has a torque convertor with the ring gear presses or heated on to the TC outer. I wonder if it might even be better to just try and source a S/H 'C-matic' box of cogs..

 

Cheers anyway guys.

[CreepingJesus]

That's presumably a bit 'specialised', then. Often as not, an auto-box flywheel's got detail differences from the manual-box one. There are specialists who can do the engineering required to remanufacture one, but maybe nosing around the owners' club to see if someone's got a good s/h one would be easier/cheaper.

[Richard]

I'm sure there must be a ring gear for another car that would do the job, somebody in the owners' club would know.

 

It could be that the bush in the end of the starter is worn, allowing the gear to lift and not engage properly.

[j-j]

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??

 

HEEEEEEEEEELP!!!!

[M'coli]

Can you bypass the solenoid? I start the Imp when working in the engine bay by bridging the contacts, usually with a screwdriver.

 

There's also the chance that having worked with things over the (relatively) warmer weekend it might be protesting again at the extreme cold of this morning.

[j-j]

M'coli, do you mean push the screw driver in the end of the solenoid and hold it fully in while it cranks over? Possibly but I think the alternator is in the way of that. If I can get something shorter to jam in there then it's a possible.

 

You can bypass the starter switch really simlpy on these because the lead for it has a bullet connector that is right next to the +ve batt terminal. Just unplug and hold the male bullet half on the batt terminal and it cranks over (normally) but it just does the same thing when trying this.

 

I just wanna understand why it is doing this!

[M'coli]

Yes I mean short the battery to the starter motor, bypassing the solenoid. It could be just because the temperature's really dropped again, too.

[j-j]

Ah gotcha, but don't you need to have the solenoid push the pinion over?

[M'coli]

Doh! I was thinking on the inertia starter that the Imp has, a pre-engaged will be different - sorry.

[j-j]

I think the one on the imp will be easier to get to anyway! on the CX it is located on front of the block but behind the exhaust manifold.. undertray needs to come off to reach (oh, that's after finding a way of jacking up the lowered hydraulic suspension! Need to borrow the work's trolley jack again!!!!

[j-j]

It is working perfectly again

 

Deffo a coldness problem to do with (likely) the solenoid's strength.

 

Will be armed with a hair dryer and an extension cord in the morning to pre heat it