Flywheel teeth prevent starter disengaging?

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Dennis1984
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Flywheel teeth prevent starter disengaging?

Post by Dennis1984 »

Hi

I have been plauged by starter motor issues for some time now and am considering taking the next step to get this sorted but hoping to get some advice and support before taking the plunge.

It started by having to change a couple of starters in quick succession. I suspected poor quality reproduction/refurbished units. A garage fitted a 'hot start relay' which is still fitted. I appreciate there is divided opinion on the benefits of these but all seemed ok for a while. Another starter failed but this time I could start to hear a whirring sound on start up that preceded the starter failing. I learned this was the starter motor not disengaging. After some research on here I saw that this could be a sticky ignition switch keeping power on so I changed that. I also replaced all the main cables and the gbx/chassis earth. All was well for a while but I have to keep restarting van multiple times until i get the right sound (no whirring) and am confident the starter has disengaged. I have just exchanged another starter and the new one displays exactly the same behaviour as my spare starter......ie ok 50% and bad 50%. When it disengages it starts perfectly.....ie not sluggish or struggling etc. so I don't think it's bad earths etc? 

On the last starter exchange I took a picture of the flywheel teeth as i now suspect this could be the root cause of my issue? I don't really know what I am looking at.........can anyone advise if condition of the flywheel teeth are preventing the starters disengaging and then ultimately failing. Also sharing pics of the failed starter teeth in case this helps.

Image20210821_144320 by chris read, on Flickr

Image20210821_144339 by chris read, on Flickr

Image20210821_144220 by chris read, on Flickr

Thanks for any advice, much appreciated!

colinthefox
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Re: Flywheel teeth prevent starter disengaging?

Post by colinthefox »

Can I take it from the pictures that this is a diesel of some kind? It looks as if the starter has disengaged, then come back against the revolving flywheel, so I suspect the origin of the problem is electrical. It would help if you would add the vehicle and engine type to your signature.

You have said that you have a hot start relay fitted, and you imply that the whirring noise problem started after it was fitted.

Do you have a split charge relay fitted to charge a leisure battery? I mean an old fashioned ordinary relay, not the modern automatic electronic voltage sensing kind.

If so then this is a long shot, but worth investigating.........

The reason I ask is that some split charge relays are wired off the ignition live as a 12v feed, and the red/black starter trigger wire as an earth return (yes really, and it works well to prevent the split charge relay pulling in until the starter has finished starting). If that is the case, it may be possible for the split charge relay to end up back feeding the hot start relay when the starter finishes working. This would put about 6V on the hot start relay, maybe pulling it in sometimes, maybe not.

You could test this rather unlikely scenario by disconnecting all the wires from the split charge relay (label them first, and don't let them short out against bodywork or each other while disconnected). If it cures your problem, you've found it. If not, it was worth a try! The split charge relay may be near the leisure battery which may be under the passenger seat, for example.
1.9D (AEF) pop-top. Aaaaahhhhh........that's better.
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