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Discussion Starter · #1 ·
I have an MSD Ready-to-run distributor with a Blaster 2 coil. Engine has been running ratty, but still runs. Just checked the coil with ign on and found 12V on both terminals. Pulled the coil off and both + and - posts show no resistance. If the coil is shot, how can the engine still fire?
I know there is an internal amplifier built into the distributor, could this be providing enough voltage to produce a spark?
It's off to the shop for a new coil in the morning....just curious if anyone can provide a better explanation.
TIA - JC
 

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A coil is just exactly that, a coil of wire. Therefore, it will have almost no resistance as measured with your ordinary volt meter. What you need to be able to do is measure inductance and know what the correct amount of inductance your coil should have. As for the 12 Volts on both sides, the way a coil works it is quite possible to have that. The only time you will see a difference is when the circuit is opened due to points being opened, or the electronic trigger opening the circuit. When the circuit is opened, the voltage drops in the coil. This drop causes the electric field to collapse, which in turn generates a high voltage charge in the secondary which is the post that feeds the distributor. As long as the circuit is closed, there is almost no voltage drop in the coil, so the + and - posts read about the same.
 

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Discussion Starter · #4 ·
Thx for the replies....I am now guessing that I have oiling issues (lifters not pumping up) or cam problems. The spark seems to be there and the engine runs better at higher rpms which makes me think the problem lies elsewhere
 
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