moparmusclecars
Well-Known Member
Anyone? One car I have has a four prong, the other car has a two prong. Both have electronic ignition which was added at some point. Can someone please explain to me the two wire ballast vs the four wire? thanks!
What's the purpose of a four prong ballast resistor?
- Thread starter moparmusclecars
- Start date
bm02tj
Well-Known Member
ignition module makes the difference the newer ones have one less pin in connector and the older ones had a separate power source
when they had a lot of failures on the fine resistor they combined them and dropped one pin
when they had a lot of failures on the fine resistor they combined them and dropped one pin
johns
Active Member
There are basically 2 circuits with the 4 post ballast, 1 one for cranking and 1 for running.
Once the car has fired and the key has been been released the cranking circuit is shut off and the car runs on the other. Both sides have different ohm ratings but are linked together with a bracing wire connecting the 2 sides. If my memory serves me correctly the cranking side of the ballast is a lot lower ohm rating (probably around 0.4) so as to aid starting by allowing more volts to flow. The run circuit will be higher ohm so as to reduce the volts (around 9 on a standard car) through the system when running. You can buy ballast`s with varying ohm ratings which will either increase or decrease your voltage accordingly but be carefull to match your voltage to your coil as they vary too.
The difference between a 4 and 5 pin ECU :
Be careful if you run an ECU as the 4 pin ECU has a built in resistor where the 5 pin ECU does not. A 4 pin ECU can be used with both 2 and 4 pole ballasts but the 5 pin ECU should only be used with a 4 pole ballast as it does not have the built in resistor and would fry quite quickly.
Once the car has fired and the key has been been released the cranking circuit is shut off and the car runs on the other. Both sides have different ohm ratings but are linked together with a bracing wire connecting the 2 sides. If my memory serves me correctly the cranking side of the ballast is a lot lower ohm rating (probably around 0.4) so as to aid starting by allowing more volts to flow. The run circuit will be higher ohm so as to reduce the volts (around 9 on a standard car) through the system when running. You can buy ballast`s with varying ohm ratings which will either increase or decrease your voltage accordingly but be carefull to match your voltage to your coil as they vary too.
The difference between a 4 and 5 pin ECU :
Be careful if you run an ECU as the 4 pin ECU has a built in resistor where the 5 pin ECU does not. A 4 pin ECU can be used with both 2 and 4 pole ballasts but the 5 pin ECU should only be used with a 4 pole ballast as it does not have the built in resistor and would fry quite quickly.
moparmusclecars
Well-Known Member
thanks for the responses, guys! I learned a lot. I appreciate it.
Nacho-RT74
Well-Known Member
4 prongs are not related with cranking and run circuit deal... 2 prongs are exactly the same.
the 4 prongs ballast provides 2 diff resistor sources. Primary Low ohm rate for the coil just exactly 2 prongs ballast and secondary high ohm rate for the 5 pins ECU. 4 pins ECUs doesn't need anymore this secondary resisitor built in into the 4 prongs ballast, because these have the secondary resistor built into the ECU module. Thats why the pin was removed from ECU, making the existant wire on to 4 prongs ballast setup from secondary resistance gets to nowhere when replacing the stock 5 pins ECU with a 4 pins ECU
NOW, why does exist this secondary resistor on Ballast OR into Modules ? dunno really which is its function. But the truth is it exists in both setups, in one or other way
the 4 prongs ballast provides 2 diff resistor sources. Primary Low ohm rate for the coil just exactly 2 prongs ballast and secondary high ohm rate for the 5 pins ECU. 4 pins ECUs doesn't need anymore this secondary resisitor built in into the 4 prongs ballast, because these have the secondary resistor built into the ECU module. Thats why the pin was removed from ECU, making the existant wire on to 4 prongs ballast setup from secondary resistance gets to nowhere when replacing the stock 5 pins ECU with a 4 pins ECU
NOW, why does exist this secondary resistor on Ballast OR into Modules ? dunno really which is its function. But the truth is it exists in both setups, in one or other way
DART340H
Well-Known Member
Thats some good info. Thanks Guys for the post. Learned something new today.
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