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VR V8 Ignition Control Module frying

Discussion in 'VR - VS Holden Commodore (1993 - 1997)' started by slappa81, Jan 19, 2012.

  1. slappa81

    slappa81 New Member

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    Hey guys, this dam car has got me stumped. I have gone through 2 ignition control modules in the past month. Distributor, and coil have both been replaced also ignition control modules. Put the 2nd one in on Tuesday arvo, car started fine, charged the battery on Wed (so car didnt move all day), started again this morning and let it run for abit, car stalled, ignition module is frying hot again and now car wont start again????? Any ideas?
     
  2. BlackVXGTS

    BlackVXGTS Well-Known Member

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    The info below is from nuclearpoweredmodules who sells refurbished ignition modules on eBay. It may be relevant to your situation given you had to charge your battery:

    "In the past I have received a few modules via exchange that appear to have been damaged by voltage spikes. These can occur in the car by not having a good battery or by not having the battery terminals clean. The car battery has a second important function in the car, it is not just there to start the car. It shorts out voltage spikes from the alternator. This is why the alternator is wired direct to the car battery before the wiring goes off to the rest of the car. (Something to watch out for if you ever remove your voltage regulator - disconnect the battery first or you may get a whooping spark!)

    How does a voltage spike occur?

    When something that draws heavy current is turned on, such as your headlights, the electric field in the alternator ramps up to deliver the extra current. When the headlights are turned off again this electric field, which is sitting in an inductive system, cannot just disappear instantly, it has to decay away. That can leave two or three hundred watts of power with suddenly no where to go. Watts = Volts x Amps, so if the current suddenly decreases then the voltage will suddenly increase (due to the laws of physics) to maintain the field. It's called an Alternator Load Dump. Alternator Load Dumps get shunted into the car battery to be shorted out. Weak batteries and damaged voltage regulators can cause irregular voltages."
     
  3. Adds_05

    Adds_05 Member

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    not really helpful but ive done this in my ss, scared the absolute #### out of me, luckly i didnt wreck anything...
     

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