z31.com | Repairs | Tuning Your 300ZX

Tuning Your 300ZX

Ignition

300ZXs are notorious for their habit of bad spark plug connections. If you have a misfire, check the plugs and wires first. They make better contact if you push the wire farther into the boot, put them on, then hold the wire and push the boot down over it. replace the cap and rotor periodically too, it can get pretty bad before you notice. When looking at the distributor from the top, turning it clockwise is advancing the timing.

Fuel

The fuel filters used on 300ZXs are standard Nissan fare and are quite good. Only in exceptionally rare cases will they be clogged enough to cause problems. They should be replaced every now and then though. The pumps are almost indestructable. That's good because they are mounted inside the tank and are very expensive. They also have no filter on the pump. The injectors and the pressure regulator are a bad problem however. Nissan is replacing all the injectors and fuel rail for free! Simply take your car to any dealer and they'll take care of it for you. It's also always a good idea to carry a fire extinguisher in any 300ZX, regardless of age. Oh, the above mentioned bad plug connections are almost always the source of ignition of the leaking fuel.

Don't use cheap gas either, stick with name brands and always try to fill up at the newest gas station you can find. This will ensure that your gas is coming from the cleanest tanks possible. And don't use gas with a higher octane than your car requires, it promotes carbon build up in the intake ports, which is a chronic problem with VG30 engines.

Electrical

Got freaky electrical problems? Check the computer for trouble codes. This is explained in detail in the any service manual. The most problematic sensor I've seen is the cyclinder head temperature sensor It can cause a wide variety of problems depending on how it goes bad. Don't trust everything the computer says either.