Strange starting issue

[Blong91]

Hi all, the last week or two my car will randomly have trouble starting. It is the 2.4 petrol.

I put the key in the car, turn the electrics on and it will start making loud and fast clicking noises (maybe 3 times in less than a second) and then everything will switch off. No electrics will work at this point and the car won't try to start.

Strangely the only thing that gets the electrics back up and running is pulling the button to pop the bonnet!

Anyone any idea what this could possibly be? I had put it down to the squeaking fan belt but I changed that at the weekend and no joy.

Thanks.

 

[freddofrog]

either one or both of the leads on the car battery are loose, or the battery is duff

 

[Blong91]

either one or both of the leads on the car battery are loose, or the battery is duff

I've noticed the ground lead is moveable by hand, but only at the part which connects to the car body itself (not the battery end). I've tried tightening this but it just seems to spin and not tighten up any more than hand-tight, could this be it?

The two connections to the battery itself are tight enough. Would the battery be okay though as the car does start every time after the bonnet has been popped?

Cheers

 

[freddofrog]

I've noticed the ground lead is moveable by hand, but only at the part which connects to the car body itself (not the battery end). I've tried tightening this but it just seems to spin and not tighten up any more than hand-tight, could this be it?

that's the cause of the problem, no end of any of lead should be movable at all

 

[Blong91]

that's the cause of the problem, no end of any of lead should be movable at all

So it's likely a case that the ground isn't strong enough?

I'll try tightening it again, but i've tried once or twice since and it just doesn't seem to want to tighten beyond handtight and will just spin.

 

[freddofrog]

So it's likely a case that the ground isn't strong enough?

I'll try tightening it again, but i've tried once or twice since and it just doesn't seem to want to tighten beyond handtight and will just spin.

it doesn't make any difference whether the +ve or the -ve is loose, it comes to the same thing.

A starter motor draws a couple of hundred amps, and any small resistance produces a voltage drop.

The amount of resistance on a loose clamp is extremely variable all the time, sometimes the resistance is bad enough for the normal electrics to just go out even when not trying to start the car.

 

[Blong91]

it doesn't make any difference whether the +ve or the -ve is loose, it comes to the same thing.

A starter motor draws a couple of hundred amps, and any small resistance produces a voltage drop.

The amount of resistance on a loose clamp is extremely variable all the time, sometimes the resistance is bad enough for the normal electrics to just go out even when not trying to start the car.

Interesting information. I'll try to tighten the other end of the ground lead later.

Thanks again