28-03-2019, 01:44 PM
(This post was last modified: 28-03-2019, 01:47 PM by AustinWood.)
I have been doing some testing on my 1929 fabric saloon ignition wiring. It has an Accuspark distributor.
For some time the car has been reluctant to start using the starter motor and never will if the engine is cold. The starter works well and turns the engine over at a good speed. It starts first pull using the starting handle.
My battery is fully charged and is connected to a conditioner to keep it topped up.
The battery voltage is 6.3 but when cranking this falls to less than 5V which I suspect is too low to trigger the Accuspark. I've long thought this to be the case but haven't got round to measuring it until today. The voltage at the coil is the same, so the wiring must be OK with no bad contacts. A direct connection between battery & coil makes no difference. The other clue is that sometime the engine starts just as the starter is switched off because the voltage rises at that moment. The starter also works if the engine is warm and hasn't been stopped for long.
This implies that the battery cannot supply the current required by the starter and at the same time supply the voltage required for the ignition. With a hot engine the power needed to turn the engine is less so the starter works OK.
My guess is that the battery is getting tired and maybe a new one is the solution. However as the car starts very easily on the handle I'm not that bothered.
For some time the car has been reluctant to start using the starter motor and never will if the engine is cold. The starter works well and turns the engine over at a good speed. It starts first pull using the starting handle.
My battery is fully charged and is connected to a conditioner to keep it topped up.
The battery voltage is 6.3 but when cranking this falls to less than 5V which I suspect is too low to trigger the Accuspark. I've long thought this to be the case but haven't got round to measuring it until today. The voltage at the coil is the same, so the wiring must be OK with no bad contacts. A direct connection between battery & coil makes no difference. The other clue is that sometime the engine starts just as the starter is switched off because the voltage rises at that moment. The starter also works if the engine is warm and hasn't been stopped for long.
This implies that the battery cannot supply the current required by the starter and at the same time supply the voltage required for the ignition. With a hot engine the power needed to turn the engine is less so the starter works OK.
My guess is that the battery is getting tired and maybe a new one is the solution. However as the car starts very easily on the handle I'm not that bothered.
Jim