I have a 71 Duster 225ci and have converted it to electronic ignition. The following diagram came with the kit. After installing it, I was told to change the ignition coil or it would not last long with the new system. I installed a MSD Blaster 2 coil, PN 8202, and the included instructions said a 0.8 ohm ballast resistor must be used. According to the ignition instructions, the included dual ballast resistor only has 0.5 ohms. Is this going to be a problem or should I ignore terminals 3 and 4 on the dual resistor and use a 0.8 ohm resistor in its place? Sorry for the dull image.
Electronic Ignition Conversion
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BillGrissom
Well-Known Member
My guess is that 0.5 ohm is close enough, what Mopar requires, and you might get another 0.3 ohm from the wiring and connectors anyway. MSD's instructions appear generic, for many engines. I would run it and see if the coil gets too hot. If so, it will start missing at high throttle, in my experience (ran without a ballast once).
The Blaster 2 is designed for later ignitions, like GM HEI, that don't require a ballast. Using it with the old Mopar electronic ignition w/ ballast is a waste. I have a coil from a ~80's Mopar (Ram Van) that says "for use with electronic ignition". I recall the same engine had the Gold box and a ballast resistor. Maybe that would be better for you.
Is this a new conversion kit? If so, why are they providing the earliest dual ballast design? Most all ignition modules you get from the store today don't even use the 5 ohm ECU resistor, even those that have 5 pins (usually a dummy). It would have been simpler, cheaper, and better performance to install an 8-pin HEI module w/ coil as I did in my slant, as have others. Then you don't have to worry about matching a ballast to the coil. If you don't want a junkyard trip, TrailBeast sells the components new for ~$100.
The Blaster 2 is designed for later ignitions, like GM HEI, that don't require a ballast. Using it with the old Mopar electronic ignition w/ ballast is a waste. I have a coil from a ~80's Mopar (Ram Van) that says "for use with electronic ignition". I recall the same engine had the Gold box and a ballast resistor. Maybe that would be better for you.
Is this a new conversion kit? If so, why are they providing the earliest dual ballast design? Most all ignition modules you get from the store today don't even use the 5 ohm ECU resistor, even those that have 5 pins (usually a dummy). It would have been simpler, cheaper, and better performance to install an 8-pin HEI module w/ coil as I did in my slant, as have others. Then you don't have to worry about matching a ballast to the coil. If you don't want a junkyard trip, TrailBeast sells the components new for ~$100.
BillGrissom
Well-Known Member
I kind of wonder the same. I think many people use the stock points coil. However, the later coil for electronic ignition has a note about that, which may be a warning of some sort. It doesn't warn not to use it with a points ignition, so my guess is it has a little more resistance than the earlier coils.
Regardless, always carry a spare Mopar module and ballast resistor, since both are known to fail regularly. The later 4-pin module will work fine with your dual ballast wiring. It just doesn't use the 5 ohm ballast. That was required for the earliest transistor designs. The only reason they put a 5th dummy pin in replacement modules today is to not alarm buyers who have a 5-pin setup (dual ballast).
Regardless, always carry a spare Mopar module and ballast resistor, since both are known to fail regularly. The later 4-pin module will work fine with your dual ballast wiring. It just doesn't use the 5 ohm ballast. That was required for the earliest transistor designs. The only reason they put a 5th dummy pin in replacement modules today is to not alarm buyers who have a 5-pin setup (dual ballast).
67Dart273
Well-Known Member
A 5 pin ECU MUST have a 4 pin resistor
A 4 pin ECU can use either a 4 or 2 poin resistor
You cannot tell a 4 or 5 pin by looking, (always) because some (aftermarket) ECU's have 5 pins, but the 5th is a dummy.
To determine, you must use an ohmeter on the odd pin to see if it's connected to anything else.
SO if you wire your car for a 4 pin resistor, you can use ANY ECU Mopar made.
A 4 pin ECU can use either a 4 or 2 poin resistor
You cannot tell a 4 or 5 pin by looking, (always) because some (aftermarket) ECU's have 5 pins, but the 5th is a dummy.
To determine, you must use an ohmeter on the odd pin to see if it's connected to anything else.
SO if you wire your car for a 4 pin resistor, you can use ANY ECU Mopar made.
BillGrissom
Well-Known Member
Sure, just search "HEI ignition". I posted photos a few weeks ago showing where the module and coil are in GM 85-95 trucks and 85-93 cars, if you like junkyard picking. Many photos of TrailBeast's kit installed and others roll-their-own setups. When I robbed some GM's, I also took the knock sensor and module (same years).
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