Scirocco Register

Car has been sat in the garage for months on an unrelated driveshaft issue. Recently put a new alternator as it was hesitating when cranking, this didn't solve the problem though.
left battery disconnected, wouldn't start first time. checked everything, changed fuel, all filters, plugs. Finally coughed into life, parked outside for a few days but wouldn't start when I tried two days later.

Checked the earths, the gearbox to chassis leg strap was melted wear it met the chassis. Put some cheapo chinese ones on, tried to start and and same one melted. Replaced coil to cam cover, box to chassis, chassis to -ve and +ve to starter with quality straps. Tried to turn it over, still hesitated then a puff of smoke from somewhere in the fusebox. Sanded all contact points to bare metal.
I'm getting so fed up and I'm broke, hoping there's an easy fix. Any ideas what could be the cause? Wiring isn't my strong point.

That strap, from the gearbox to chassis to battery, is the earth point for your starter. And the starter "should" be the only thing capable of drawing enough current to burn out an earth strap so this points me to a faulty starter motor.

Take it off and check it turns relatively freely by hand, if so power it up clamped tightly in a vice. You can hold it if you're brave but it will kick quite a bit when it gets going.
If it won't turn it will draw a massive amount of current when you try and start the car.

If the starter works fine take your plugs out and try and turn the engine over by hand (ratchet on the crank bolt). It should turn relatively freely without plugs in. If it's hard to turn by hand you NEED to find out why. This will cause the starter to draw more current than normal.

As a side note a starter under normal conditions can easily draw upwards of 100 Amps. This is enough to weld with, if it's stalled, it can and will draw much more, hence the melted earth strap.

Ben.

Thanks for the pointers mate. Starter makes sense, I assumed from the fact it was trying to start that it was working. I'll whip it off tomorrow and have a look.

New starter didn't change anything. It's getting power, just seems to be getting no signal from what I assume is the ignition wire.
I can't make much sense of the wiring diagrams in the Haynes manual, I assume the smoke from the fuse box was that wire burning out but I can't see any signs of damage at all.

Put a multimeter between the small starter wire and the battery earth and check voltage when cranking. Should be near enough battery voltage.

Ben.