bad starter

[greystag]

has anyone had bad starting due to ignition electrics. coil has 12.4 v but when trying to start it goes down to 9 v, which i think is the problem, should i replace ignition unit and maybe wire in relay seems to me it could burn contacts.any help would be appreciated.
Regards Terry

[Guest]

Can't help you Terry, but might be useful to know a hit more detail, such as whether the ignition system has a ballast or not.

[greystag]

iv always assumed it did not have a ballast as it shows 12.4 v. but to make sure i will replace ignition and wiring to coil.
Terry

[Lingen]

Terry. Even with a ballast system it might show battery voltage if the points are "Open". The coil has to be earthed before the ballast resistor drops the voltage, so check that first before replacing anything. It usually falls to around 7.5 volts with a closed circuit. If the bypass supply to the +ve on the coil from the starter motor solenoid is in place, you should get battery voltage at the coil when the starter is operating.
Mike.

[greystag]

bad starter

Terry. Even with a ballast system it might show battery voltage if the points are "Open". The coil has to be earthed before the ballast resistor drops the voltage, so check that first before replacing anything. It usually falls to around 7.5 volts with a closed circuit. If the bypass supply to the +ve on the coil from the starter motor solenoid is in place, you should get battery voltage at the coil when the starter is operating.
Mike.

thanks for that mike,i have a dizzy with electronic ignition,does that make a difference to how to test,also i take your point about the feed from starter ,it does not have one,could that be the answer,
Regards Terry

[mjheathcote]

The whole idea with the ballast system (early cars -resistor on side of coil, rest -ballast wire in loom), is that the coil is nominally 6v when running normally (due to voltage drop because of the ballast system), but when you start the car on the starter motor only, the ballast system is by-passed so the coil gets a nominally 12v 'boost' until you release the key. Quite simple and clever really.

[Lingen]

Terry. As you have no points to close with electronic ignition, you can create the same effect by temporarily earthing out the -ve terminal on the coil to test the +ve voltage. Don't leave it on there too long.
If you find you have got a ballast voltage present, then make sure you have a ballast coil fitted, as a 12v coil will hardly work at all. If you have a ballast resistor and coil, then without that temporary 12v feed from the starter solenoid, hot starting can be almost impossible,. That is why the system is there. That, as you say, could be the answer!
Mike.

[mole42]

has anyone had bad starting due to ignition electrics. coil has 12.4 v but when trying to start it goes down to 9 v, which i think is the problem, should i replace ignition unit and maybe wire in relay seems to me it could burn contacts.any help would be appreciated.
Regards Terry

Have you changed anything before the bad staring presented itself?

[flying farmer]

About a week ago I had a ballast resistor fail on my Stag engine estate, fortunately only about a mile from home. The engine just switched itself off, but would fire while cranking and the bypass from the starter was working.
Fortunately I happened to have a reel of wire in the glove compartment, and using my teeth as wire strippers, managed to hot wire the coil straight from the battery to get me home.
On removing the ceramic ballast resistor (it is a 1971 car), where the resistor wire was riveted to the spade terminal it was corroded. Fortunately I had a spare in the garage.

A couple of years ago I had the opposite failure on the same car, the bypass wire fell off the starter and it refused to re start when I switched it off in the queue to get into Stoneleigh. I realised the nature of the problem when the car would not fire while cranking, but would fire just once each time I released the key as full voltage suddenly reached the coil.

Neil