Having problems with your 1990 Nissan 300ZX ?
No spark - 1990 Nissan 300ZX
I am having the same problem on my 90Z. I tested my coils and they were good so I tested my PTU and wire e2 on the 6pin connector is showing 0.24 volts. I also checked the coil plugs and found that the ground is good and the first wire has 12 volts but the second wire has 0 voltage. Does anyone know what is causing this and where to look?
Check the power transistor unit (the small black box on the front of the engine, passenger side, slightly beneath the main black intake hose coming to the intake manifold). It has six or seven wires coming in one side and out the other. That part was the one warranty recall for the Z from 90-96. I'm not sure what year yours is since the question is listed as a generic 300ZX question, but the recall affected 1990 models and a few early 91s. The PTU was redesigned with a heat sink to keep it from overheating (the main reason determined to cause the failure). This is the unit that drives the signal to the coil packs to fire the plugs. If it dies, you'll have no spark and the car won't run unless it decides to revive itself or you change it. If that doesn't fix the problem, I'd look into the CAS (metal circular sensor, front of the engine, driver's side, one harness plugged into the side) - that is the cam angle sensor and can cause you to lose ignition as well.
Repair Help & Product Troubleshooting for 1990 Nissan 300ZX
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