Originally Posted by
blindsquirrel
No sir, you didn't do a voltage drop test, you were just straight out measuring voltage, and a voltage test doesn't show the small numbers you need to pin down a high resistance issue, if that's what this is.
Voltage drop is measuring the difference in voltage at two points along the same wire/circuit. The meter needs to display the difference between 'ground' at the coil pack connector pins and 'ground' at the BAT negative. This will be a very very small number if the circuit is in good shape, and larger as the circuit has progressively higher resistance.
Put your meter positive probe to one of the ground wires in the coil harness, and the meter negative probe straight to BAT negative. Both leads on only the ground side of the circuit, don't connect anything at all to the positive anywhere. You're only measuring the difference between 'true' ground and the 'ground' available to the coil primary circuit(s). Going from coil negative to battery negative will be checking the entire circuit through all the wires, splices and connectors in the entire ground circuit. To pinpoint where exactly the problem is, move your meter negative probe to another spot in the circuit, see if the same excessive voltage drop is present there as well. Basically split the whole circuit into halves - still problem, or no? If no, problem is in the other half that was eliminated. Check only that second half. Problem still? It's in this half somewhere, so split it in half again. Keep doing that and it will lead you straight to the splice, or wire, or connector where the problem is.