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Location:
Canberra
Registered:
February 2004
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Multimeter anybody?
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Fri, 25 June 2004 02:19
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HI, I was wondering if anybody has tested their cold start ballist resistor function recently. To the best of my knowledge, when you turn the key in an RA40, you bypass the ballist resistor and the coil gets a full 12 volt current from the starting motor. Has anybody tested their coil with a multimeter and noticed a rise in current? If so, do you know where the connection between the starter and the coil input is? I am trying to make up for the previous owners half assed improvements (We've all been there). Thanks for your help.
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Location:
Sydney, Peakhurst
Registered:
May 2004
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Re: Multimeter anybody?
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Fri, 25 June 2004 02:49
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1. there is no such thing as a 12 volt 'current'. current and voltage are different entities.
2. there is no connection between your starter motor and your coil.
3. you cannot possibly notice a rise in current with your multi meter. Think Voltage-voltage voltage!
4. yes you will get a rise in voltage, that is what a coil is designed to do, take 12-14 Volts and build it up to very high voltage (low current).
I have nerver heard of any ballast resistor in an ignition system (not to say it doesn't exist).
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Location:
Brisbane
Registered:
May 2002
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Re: Multimeter anybody?
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Fri, 25 June 2004 03:33
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Older ignition systems commonly had ballast resistors; the idea was to run the coil off ~8v most of the time, but while cranking the resistor is bypassed, thus increasing the strength of the spark as the coil is getting the full 12v (which of course is multiplied to thousands of volts). If you buy an ignition coil from Repco et al you'll notice that some are designed for use with a ballast resistor, and some without.
As for the original question, there should be two separate power feeds for the ignition coil. One circuit is live when the ignition switch is in the "on" position and this goes through the ballast resistor; the other circuit is live when the ignition switch is in the "start" position (ie when cranking) and this bypasses the ballast resistor.
If you can get your hands on a circuit diagram for your car (or pretty much any Toyota from the era) it should be pretty obvious what's going on.
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On Probation
Location:
North East NSW
Registered:
December 2002
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Re: Multimeter anybody?
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Fri, 25 June 2004 05:29
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haynes manuals sometimes have a wiring diagram, as well as a wiring map, which gives locations and connectors of some things
or you could try having a look in the factory manuals for your car at your local toyota dealer service, if you ask nicely they often let you take photocopies too
my ballast resistor sufficiently annoyed me to remove it, and fit a coil "for use without ballast resistor". to my understanding, these coils just have an internal resistance
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Location:
Canberra
Registered:
February 2004
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Re: Multimeter anybody?
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Fri, 25 June 2004 16:02
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Thanks guys,
I'll have to have a look through the circuit diagram. I'm not an automotive electrician by any twist of the imagination so I reckon that I ment voltage instead of current. Thanks for the reply though.
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Location:
Canberra
Registered:
February 2004
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Re: Multimeter anybody?
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Sat, 26 June 2004 00:06
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In answer to tripmcneily's 1-4,I have to say
I'm not a Gynecologist but i'll take a good look!
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