Sounds like a bad wire in the conversion hanress. Leave the harness connected and run a continuity test from the ecu conversion harness to the crank angle sensor wires on the distributor plug. There are two wires related to the crank angle sensor. If you don't have continuity with the harness attached try it without and use the obd2 pinouts. Sounds like a wire has a break or is crossed.
Tuner won't be able to do much if your car has a code 4. Don't worry about the 41.
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Gracie Barra Clearwater
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