Ammeter Problems?

[Robert Hiland]

I have a 1967 Series 1.

The ammeter does not defect under running conditions but the car runs fine.

If I charge the battery with a charger and switch on the ignition, it shows a charge.

What's up?

Bob

[Gfhug]

Bob, ammeters normally show little charge when running, almost not noticeable, but a large charge shortly after engine start, does yours show this? The large deflection reflects recharging the battery after the heavy load of starting, then a trickle under normal running.
If yours shows no deflection at all after start up then is it a bad generator/alternator/regulator?

Good luck
Geoff

[malcolm]

I think that Bob's issue is that the ammeter shows a charge when the ignition is on but engine not running - if so, it sounds like a duff ammeter.
If Bob's point is that with engine running after starting, a large charge is shown even though basttery has been fully charged, then Geoff's point is spot on. Even a fully charged battery takes a big hit on starting, so you should see a large charge initially followed by a reduction to nearly nothing as geoff says

[Robert Hiland]

When the engine is running, I can turn all loads and the ammeter shows nothing. Have I got an open circuit somewhere? Yes, it could be a faulty ammeter. How does one test this without buying another one? Thanks for your input.

Bob

[Heuer]

With the engine off turn the headlamps on to full beam - the ammeter should move to the right of centre. If it does not you have a faulty ammeter. Basically all current from the car goes via the ammeter (thick brown wires) and it will deflect to the left when the battery is being charged although only if the regulator deems it requires a charge. It will deflect to the right only if the power drain exceeds the current being generated by the alternator. Current will still flow to the car electrics if the ammeter is faulty. You can get it repaired by Speedograph Richfield or Speedy Cables or fit a voltmeter in its place - a much more useful device on an alternator equipped car! Full instructions here: viewtopic.php?t=166

[Robert Hiland]

Thanks for all your help. It would appear that a replacement ammeter is the answer.

Another item on the "to do" list.

[David Oslo]

Be sure to do the checks with the engine off.

I'm used to dynamo cars and mechanical regulator units, being able to use the ammeter as a useful tool when driving. Upon purchasing the E-type (with alternator) I was immediately concerned over the lack of charge (e.g. poor display deviation) however subsequently learned that this is normal when things are fine and working as they should.

As David says a voltmeter would be a more useful gauge. So make sure to check what the issue is before buying a new ammeter. I have exactly the same car as you.