Hi, this is my first post in this forum and I came because I have a weird problem with my nissan.

every day my car was working well until one day walking switches off after 20 minutes I start it, the next day will not start if there is spark at the spark plug. and all day I could not get it to start.

The next day I try to start it and it started on the first try, use it all day and it worked fine. But the next day will not start, but if I put gasoline direct the air flow starts at the time then turns off.

The relay seems to be well.

the computer has power but no pulse at the injectors, and check the electrical connections and all is well.

It is about the temperature sensor to the pulse of the injectors?

why a day starts well and the next day not start?

First: Download the Fuel Injection Bible from the Members\Downloads section of this forum.

Second: Follow the Link http://www.mediafire.com/?y2x2e66oh939z9t to download the 1978 280Z Factory Service Manual.

Study the EFI Manual and debug one part at a time. Post Questions. We will all help you.

Have you connected a fuel pressure gauge to see if the fuel pressure is consistent? Also important to check all the electrical connections for the "green" corrosion every so often.

If your ECU has power and you are certain there is no pulse at the injectors, you might have a bad connection (or disconnection) between the (-) terminal of your ignition coil and the #1 terminal of your ECU. This is the signal the ECU uses to trigger injector pulses.

It's also possible you don't have +12V to the drop resistor assembly (beneath the master cylinders), then feeding to the injectors. You can test this at the ECU connector, per the instructions in either the Factory Service Manual or the EFI Bible.