Hey all My issue is I have no power to one coil pack. I have checked spark plugs coil pack by changing them around and no change when pulling coil pack plug in idle. I have also replaced the ptu with no change. the strange thing is, I have no power from the negative battery terminal to the centre pin of the coil plug but I have 12v from the positive battery terminal to the centre pin of the coil plug ♂️ I also only sometimes get continuity from the plenum ground and the coil plug ground, and then both pins either side of the power pin give me ground from the coil pack plug ♂️ Any help would be really really appreciated.
Check the following 1 - All P.T.U connections for corrosion. 2 - If P.T.U wiring has been joined near plugs check wires are soldered and heat shrink properly (some people just twist and tape). 3 - Some of the ZX coils have a spring and carbon contact barrel in side the spark plug boot end make sure it is their. 4 - Are the coil plugs wired correctly ? ( compare the wiring to other coil plugs ) 5 - Check the e.c.u plug in the passenger footwell is seated correctly and mounting bolt is tight. (if it was me looking at it I would get a wiring diaphragm and do a continuity test of all the coil wiring between the coil plug and e.c.u plug for breaks) Happy Issue Solving
I am a little confused by what you wrote. There are three pins on the coil connector. 12v power is supplied to pin B (the middle one) via the ignition coil relay. The way to check this is to turn ignition to on abs put a multi meter between pin B and earth. Pulse signal is supplied to pin C (left looking into the connector; it will be the one with a coloured wire) via the PTU. Confirm you have pulse signal by using a logic probe on pin C. A multi meter will not be fast enough to register a pulse signal. The coil circuit is earthed through pin A (thin black wire) and Earth can be verified by checking for continuity between pin A and ground. See https://www.300zx-twinturbo.com/cgi-bin/manual.cgi?list=ef&slide=11 If you are missing 12v power as your title suggests check for continuity between pin B and the ignition coil relay, and the ignition coil relay and positive battery terminal.
