Hello, I have recently picked up interest in a pair of Datsun 280Zs. I was told if I could get them running that I could have them, the problem is they haven't ran in over 10 years, and might be seized. If they aren't seized what is the first thing to check before trying to start them, and if they don't start what do I check first? I know the basics are spark and fuel, but I don't know anything about the fuel injection.

 

Ok, congrats! I hope you get them running.

You're missing one thing in the basics and that's air. You need fuel, fire and air to make things go.

After sitting for 10 years, you need to flush the fuel lines cuz that old gas is likely to be varnish by now. You might want to flush the tanks as well.

Change all your fuel filters. Change the oil and that fillter too.

Air: Check your whole air flow path. Air filters might be gunged up. If they are, change them. I'm a carb guy so I can't tell you much more about things like the air flow meter (AFM) but I hope others will.

Spark: Of course battery has to be fully charged. Check your distributor cap and rotor, make sure they're clean or just replace them. Your wires may be old and cracked, replace them if they are. Just go ahead and change the plugs too.

If these cars ran when they were parked, your electronics for the fuel injector system may be ok. Again, I'm a carb guy so others will chime in on getting old injectors to work.

Motors: Pull the plugs and insert a little bit of something like Marvel Mystery Oil in the holes. Not a lot but enough to provide some lubrication to those cylinders and rings that have been sitting idle for ten years. Let that stuff sit and then put a socket (big, I think 27mm?) on the crank and see if the engine will turn by hand. If it does, AWESOME, if not, walk away. Turn it slowly for a couple of revolutions and be done. Let the oil do its thing. Put the plugs back in and be sure your wires are hooked up in the correct firing order.

Starting: You didn't say if these things were running when they were parked. I'll assume they were. That means the electronics were good then and for the most part, they still should be. Relays and other electromechanical stuff, well, we'll see. Attach the battery. You did disconnect it while you did all that other stuff, right? Watch the ammeter, is it going crazy? If so, disconnect the battery and chase down that problem first. If not, hell, I'd give it a crank and see what happens, with a fire extinguisher nearby of course. When you put the ignition to RUN, you should hear your fuel pump start up. If not, you have to chase that problem. Let the pump pressurize your system for a little bit - after all, you just flushed the system and changed the fuel filters - gas needs to get to the injectors from the tank and that will take a little time. Start it! If it doesn't turn over, there's another problem you have to chase. If it does, hopefully it will fire. If not, you can check spark using a timing light or other methods. You can check fuel pressure with a gauge, but again, I'm a carb person. Others will help you here.

Good luck and let us know how it goes.