Datsun 280zx wont start all of a sudden

[siteunseen]

A lot of people delete the CSV for the problem it caused you. One less problem it seems. I live in a warm climate so it has no bearing on my 280. If I remember right it just knocks a couple of seconds off cranking anyway. You may have to turn it over twice without it? Overkill in the early EFI systems. The newer ECUs measure the ethanol content for cold start-up.

[TerrenceW]

7 hours ago, Dave WM said:

Now you can trouble shoot that, it could also be the thermotime switch, less likely as it tends to fail off, but easy to find out. try hooking up the CSV to a 12v source, use some clip leads to it and supply a 12v (unplug the csv from the wire harness, connect the 12 directly to the csv, never the harness) it should "click". if not its prob stuck, you maybe able to get some carb cleaner into it and try cycling it a lot with the outside source.  Not a bad idea to run some good fuel injector cleaner with your next tank full of gas.

I thought about it more, the thermotime ONLY gets 12v during the crank so even if it was stuck on, the only thing that would happen is the injector would fire regardless of temp and would fire as long as you held the ign in the "start" position. I don't think that would allow enough time for the flooding you are having. So pretty much has to be the injector.

Ahh okay, well then it is weird that the engine now runs perfect without the CSV.

[Dave WM]

8 minutes ago, TerrenceW said:

Ahh okay, well then it is weird that the engine now runs perfect without the CSV.

what are your engine temps when starting? as mentioned its really only for cold climates, I presume your location is cold now. When the EFI is working right it pretty much starts in a fraction of a second. and you can drive right off. it works well when everything is perfect. I don't know if you car has an o2 sensor, if so it is a little smarter in that it can go into closed loop and try to compensate for problems with the fuel mix. the early ones (like my 75) work great as long as every sensor/injector is work properly. The is no feed back from an o2 sensor for the ECU to compensate with. Glad you got it working, if it works well without it then you have a simple fix. plug it. If it every starts being hard to start when its very cold, you can revisit this.

[TerrenceW]

4 minutes ago, Dave WM said:

what are your engine temps when starting? as mentioned its really only for cold climates, I presume your location is cold now. When the EFI is working right it pretty much starts in a fraction of a second. and you can drive right off. it works well when everything is perfect. I don't know if you car has an o2 sensor, if so it is a little smarter in that it can go into closed loop and try to compensate for problems with the fuel mix. the early ones (like my 75) work great as long as every sensor/injector is work properly. The is no feed back from an o2 sensor for the ECU to compensate with. Glad you got it working, if it works well without it then you have a simple fix. plug it. If it every starts being hard to start when its very cold, you can revisit this.

I live in holland so its only a few degrees outside right now. If the engine will start up hard i think i will get a new CSV but for now i will delete it. Also i dont have a O2 sensor. What type used the O2 sensors? I have a 1983 280zx 
also deleting stuff like this will make the engine look cleaner haha

Edited January 26, 2021 by TerrenceW

[Yarb]

The 83 280ZX o2 sensor is located at the tail end of the exhaust manifold near the exhaust pipe flange.

[Zed Head]

I think that emissions efforts were driven by the States, mostly California, the LA basin, because we have so many cars and burn so much fuel.  Choking on the smog.  A 1983 European model 280ZX might not have an O2 sensor, or a catalytic converter.

Can't find a reference source but I'm also pretty sure that many non-States 280Z's still used carbs for quite a while after EFI was introduced.  

 

[TerrenceW]

1 minute ago, Zed Head said:

I think that emissions efforts were driven by the States, mostly California, the LA basin, because we have so many cars and burn so much fuel.  Choking on the smog.  A 1983 European model 280ZX might not have an O2 sensor, or a catalytic converter.

Can't find a reference source but I'm also pretty sure that many non-States 280Z's still used carbs for quite a while after EFI was introduced.  

 

I indeed have no O2 sensor and also no kat haha, just a straightpiped 6 cillinder. best sound ever!

[dutchzcarguy]

Euro version of the 280zx never had a cat or O2 sensor..  We had only dirty cars!