My Mazda Demio had an odd starting problem this (warm) morning - on turning the key, instead of the starter turning over, instead I just get a nasty repeating 'rattling' or loud ticking sound, almost as if the solenoid is oscillating back and forth repeatedly.

But even more strangely, the dashboard went completely nuts! All the warning indicator lights flashed on and off in time with the noise, and all the needle indicators (temp, fuel, tacho, speedo) all shot over to full-scale! I've never seen the speedo needle hit the upper end-stop before! On turning off the ignition, the needles all return to zero.

Did this about four times before I decided to just leave it alone and get some assistance.

I'm really just curious as to what might cause such a problem.

2003 Demio, Japanese-import, 1.5L manual.

 

Ok, I have a theory now.

I think that one or more teeth from the ring gear are missing, and the starter pinion is hitting one of the existing adjacent teeth, but there's no mesh so there's no engine turn-over. Instead, the starter just spins but does nothing except make an awful sound. This should be pretty easy to check in the daylight, and explains why it hasn't been seen before (car has only just been purchased from an imports dealer).

I checked again and this time noticed that the dash needles going full-scale only happens just after the key is turned back from ignition to ON. When the starter is actually energised, the needles are normal. Only when switching back to ON after a failed start do the needles all swing full-scale then back again to zero. Perhaps a CPU reset condition?

 

Turned out to be a flat battery - original lasted seven years but died overnight. Noise was solenoid banging around, like a machine gun.

Apparently it's a common symptom of a flat battery, but obviously not amongst users here.