Ignition left on. What's the likely damage?
Discussion
Whilst trying to crank my car for the first time in a few weeks i got detracted and taken away from the task at hand. This had unfortunately lead to me leaving the ignition on for 24 hrs. I know that prior to this the ignition was fine and sparking correctly. I have replaced the coil and still no spark. Is it likely that my ballast resistor and disi are also damaged? It is a Mallory disi with an electronic points conversion. The conversion is about £70 a pop so I'm hoping it is okay!
Thanks,
Jack
Thanks,
Jack
So i did the coil test of connecting the red multimeter lead to ignition side of coil and black lead to earth. I had a reading of 7.1v. I assume my ballast resistor is okay as if it was fried it would surely be reading 0 or 12v?
Then, i did the test demonstrated here
https://www.youtube.com/watch?v=PSiw4thM21k.
Which is:
Remove both the distributor cap and rotor, then turn the ignition ON but DO NOT START car.
Now connect your Red voltmeter wire to the NEGATIVE terminal (-) on the coil, by attaching the Red lead wire clip from voltmeter to the (-) terminal.
Next attach your Black voltmeter wire to an engine ground on a good ground source. We suggest a manifold, or header bolt. Most anywhere on the engine is good.
Now the voltage should read about 11 to 12 volts at this point. Remember to turn the key on for this reading! 12 volts must be present on your voltmeter.
Next, place a credit card down into the distributor, blocking the 2 photo optic eyes on top the module facing each other on the top. With eyes blocked, the volts should drop way down below 2 volts or less. This drop is a must! If the voltage drops down to anything under 2 volts, then the module is good and ready to use. If the voltage does NOT drop, the module will need to be replaced.
This damage could have been caused by many things, such as: power surge from an alternator, high resistance spark plugs and plug wires, improper ground wires, if someone has given you a jump, if you have given someone a jump, or battery chargers, which can also damage ignition modules. If voltage always stays below 2 volts and never increases up to 11-12 volts, then the module has been spiked by high voltage and needs to be replaced.
I had a consistent reading of 1.14 with the optic eyes clear and obscured. I did not see a 12v reading.
I conclude that the Mallory Unllite module is fudged. Is this likely to be a correct diagnosis?
Then, i did the test demonstrated here
https://www.youtube.com/watch?v=PSiw4thM21k.
Which is:
Remove both the distributor cap and rotor, then turn the ignition ON but DO NOT START car.
Now connect your Red voltmeter wire to the NEGATIVE terminal (-) on the coil, by attaching the Red lead wire clip from voltmeter to the (-) terminal.
Next attach your Black voltmeter wire to an engine ground on a good ground source. We suggest a manifold, or header bolt. Most anywhere on the engine is good.
Now the voltage should read about 11 to 12 volts at this point. Remember to turn the key on for this reading! 12 volts must be present on your voltmeter.
Next, place a credit card down into the distributor, blocking the 2 photo optic eyes on top the module facing each other on the top. With eyes blocked, the volts should drop way down below 2 volts or less. This drop is a must! If the voltage drops down to anything under 2 volts, then the module is good and ready to use. If the voltage does NOT drop, the module will need to be replaced.
This damage could have been caused by many things, such as: power surge from an alternator, high resistance spark plugs and plug wires, improper ground wires, if someone has given you a jump, if you have given someone a jump, or battery chargers, which can also damage ignition modules. If voltage always stays below 2 volts and never increases up to 11-12 volts, then the module has been spiked by high voltage and needs to be replaced.
I had a consistent reading of 1.14 with the optic eyes clear and obscured. I did not see a 12v reading.
I conclude that the Mallory Unllite module is fudged. Is this likely to be a correct diagnosis?
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