Hardway

Voltage drop when connected to coil and other questions

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Good afternoon fellow Z owners!  Working through an issue on my '72 240z that seems to be somewhat common but with no common solution.  Engine does not run smooth, shakes at idle, ignition timing set to 9 degrees BTDC at 900rpm.  When accelerating under load it pops and backfires but not all the time.  Fuel system is set to 3psi and per the gauge runs this all the time.  I am running a Mallory 2363901 distributor with the UniLite electronic ignition module. Tach works in car.

Baseline: Key set to Run, Battery = 12.14V.  Using an Accel Super Stock coil 8140C. Mfg spec is 1.4 ohms Primary and 9.20K ohms secondary.  Mine reads out 1.7 Primary and 11.61K Secondary.  I was using an older MSD Blaster 2 coil but its Secondary resistance was over 2x the Mfg. spec.

Power going to ballast blk/white wire = 11.08V.  On the other side of the ballast grn/wht wire = 6.36V

The positive blk/wht wire on the coil when pulled off the coil is 11.80V but when plugged on to the coil = 5.49V  The condenser is also connected on the other side of the + side of the coil.

The solid black wire on the negative side of the coil produces a solid tone of continuity when grounded to the car and when it is connected to the coil.

1. Is the voltage drop on the + side of the coil expected with the power wire is connected to it?

2. Should I be seeing 12V on the power side of the ballast instead of 11.08V?  Is the drop of approx. 5V through the ballast expected?  Do I still need the ballast since I am running electronic ignition?

3. Do I need to have the condenser attached on the + side of the coil since I am running electronic ignition?

4. Do I need to buy a new coil at this point?

Thank you in advance!

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