I have a 1990 300zx. It has no spark. I got the manual and checked everything it said to check and i find no faults. Ive tried to bypass the ign relay still no spark. I can here my fuel pump prime and smell gas after trying to start it. I have a spark tester and there is no fire. I recently replaced the cas to see if that helped and no go. I check continuity on the wires from the relay and cas to the ecu and all test fine. I did a logic probe on from the ecu from the ptu cas wires per the service manual and my logic probe only pulsates on the green led the red doesnt light...should the red and green alternate as im turning the motor over. I checked continuity on the orange wire at the ign relay and is good but the ecu doesnt ground the wire to engage the relay. Im not sure why, but jumping pin 3 and 5 on the relay plug doesnt give me fire either. I think this may have something to do with the no fire. I need some help or guidance.