300tdi Starter Motor not disengaging

[Challo]

Hi there, having an issue with my 1996 110.

Got home on Thursday evening and the "Planning Committee" asked me to move my car so she could get out the drive.

Move a foot forward or so and there was a bang.

Reversed back and there was lots of slop in the drivetrain that wasn't there before.

10 minutes later started it up and the starter motor would not disengage.

Also starter tries to spin in ignition on position.

Tried again, same.

So I'm thinking started solenoid.

Thought I would open bonnet n have a looksee.

But it's jammed shut and won't release.

It's chucking it down, been up 17 hours, done 14 hour shift day before n gotta be up in 7 n half hours so borrows Dads car.

By this time I was losing the will to live.

So this aft I change starter motor with a spare i had and an isolator switch that was badly worn.

Noticed flywheel had some burrs on edge of teeth where starter engages.

Started up and it's exactly the same.

Still tries to start in ignition on position.

The 110 has an immobiliser where in the on position you have to place a fob near the ignition for the lights to come on.

Now you put it in on position and starter cranks slowly, without any input from the fob.

So now I am thinking its the ignition switch.

Does this sound correct?

Any help greatly appreciated.

Cheers

Chris

[Challo]

Any ideas anyone?

[Challo]

Was thinking re-do earth from starter solenoid to starter mounting to block then another earth from same stud to chassis to earth.

Then if no joy wire ignition to a temporary spare switch to crank.

Then if still no luck immobiliser or starter relay?

Which is starter relay If there is one?

Thanks again

Cheers

Chris

[western]

try swapping the start relay, IIRC it's a 4 pin 30amp relay.

[Challo]

Cheers Ralph,

I'll give that a try and report back.

Thanks

[Green Bob]

If, for some reason, the ignition feeds to stop solenoid and starter relay have chafed or melted, they could be feeding each other I suppose. May be worth taking binnacle off just to have a look?

[Challo]

Thanks for ideas.

Had a tinker this aft.

The starter relay is fixed to the bottom of the fuse box above the transmission tunnel. It is yellow in colour and part number is YWB10027. It is the relay located nearest the clutch pedal.

Have removed a redundant alarm and associated wiring and re-connected immobiliser loom.

Have now found if I remove the starter relay whilst the engine is running, the starter motor disengages.

Swapped with identical relay next to it and identical results.

Ran out of time at that point.

So now I am thinking isolate each wire individually until fault ceases then trace that wire hopefully to the cause of the fault.

Cheers

Chris