oldschool2

Thanks for the input! I need clarification on "bypass." What are you by-passing? The Valve Assy Fuel Check? The heat soak/vapor lock I mentioned is a separate problem. With no pressure build-up in the fuel tank due to the hole in the gas cap I still am unable to restart the engine without raising the hood (to speed-up cooling) and waiting 10 to 20 minutes. I have read numerous posts regarding this problem (cars in general, not just the Zcars). I have not heard anyone mention that when the pavement is maybe 150+ degrees pushing hot air up, and the engine and undercarriage is around 200 degrees pushing hot air up/down sandwiching hot air from two sources (payment and undercarriage) the fuel seems to vaporize in the fuel tank and fuel lines. Before I drilled a hole in my gas cap I drove about 40 miles in 110+ degree temperature. I stopped the car, shut off the engine and loosened the gas cap. There was so much pressure (not Vacuum) in the fuel tank that gas came squirting out in high volume. I was just barely able to retighten the cap. That was when I decided to drill the gas cap.

Thanks for the input. I have previously contacted and ordered the Valve Assy-Fuel Check part from the AZ company. It is due for delivery within the next two weeks. I hope it helps solve the problems I have as I paid triple the list price. As an update: I have drilled a hole in the gas cap to eliminate the excessive pressure build-up in the fuel tank. Now no more pressure (not-vacuum) problems, and the affected fuel pump is quiet now that it is not working so hard. This is in 110+ degree weather (Las Vegas). I have about concluded that the 280zx is unable to handle these extreme temps. The combination of fuel expansion in the fuel tank and heat soak/vapor lock "symptoms" makes this a car suited for below 90 degrees driving only. I have replaced almost every part in the FI system, including removing the strainer in the fuel tank (I added the fram inline before the fuel pump). Everything has helped the car run excellent except for the fuel tank pressure (now solved via the hole in gas cap). Plus the start-up problem when trying to restart after driving in 110 (in shade) temps. I have also wrapped the fuel lines with insulation. I have noted that the 300zx has a fuel temp sensor. Not sure of it's purpose. I just know that this seems to be a common problem and some desert runners say they have no such problem. These old Zcars have frequently been modified to the extent that there is no telling what is or is not under the hood. My car is not modified.

After many searches and questions I was told today by Courtesy Nissan in Texas that their data base was messed-up (this means all nissan dealers DB is wrong) for this particular part. The correct PN for the Valve Assy-Fuel Check is PN 17330-P7103 (this is for 1982 and 1983 ZXs). Bad news is that the part is no longer available. At least I (hopefully) have something solid to go on.

OK, to clarify I am looking for a source to buy the subject part. It is located "under the car" next to the fuel pump which is "under the car." This part is a part of the "Evaporative Emissions Control System." This part allows air to flow into the fuel tank and fuel vapor to travel from the fuel tank to the carbon canister. Courtesy Nissan in Texas and local United Nissan are unable to ID this part. Also, Motor Sport and Black Dragon do not carry this part. This is a major part of the Emissions System and no one can ID it. I will attempt to attach a photo of the part. If I am successful the PN noted on the pic is apparently not correct (PN 17330-P7900).

Reference Haynes manual Page 59: I am trying to locate a source for the subject part. No luck so far. Nissan Dealers have poor reference drawing for the 280zx. This part is under the car near the fuel pump and under a cover plate. The part is generally between the fuel tank and the Carbon Canister and is referred to as Fuel Check Valve. I am generally trying to eliminate excessive pressure in the fuel tank in hot weather (100+ degrees).