Earlier I was going to suggest that he could probably make the car pass just by tweaking what he has.  And he might still be able to do that,  As he figures out what he has and how it's supposed to work he'll probably also figure out how to make the oddball parts work.  Eve if he finds all of the original parts he'll still have to understand how they work.

There's really not much to the EFI systems.  Fuel pressure, air flow, and timing (cam and ignition), are the biggies.  

As mentioned prior, there's a whole lot modified on that system, and much of it done poorly.

PCV connected, but valve cover vented to atmosphere.
AFM mounted sideways.
Static fuel pressure instead of varying with manifold vacuum.

I don't think that's a stock throttle body. Looks like they threw an aftermarket one at the car because it's supposed to be "better". What's with the short stub of tubing that comes off the throttle body and goes to where the cold start valve used to be? Which side of that throttle butterfly does that tube come from??? It looks like the butterfly may be completely bypassed by that tube? Hopefully on that aftermarket TB, it comes from the high vacuum side, because if not... Sheesh!

My humble opinion?  The easiest route forward is to put most of it back to stock. Either that, or you will need an expert. Pay for one, or become one yourself. See if you can get the box of old parts the neighbor kid took off and put most of them back on. Someone threw a lot of time and effort at that engine, but I don't think they did it any good.

I am going to start all over.

get some NEW plugs, run them at idle for 10 min, pull them and get some pictures.

get some close ups of the injectors as ZH mentioned.

Lets go from there. With out a way to read the exhaust gases while tweeking its going to be up to reading the plugs for now.

the hope is you can salvage what you have without having to start all over (may need to at some point but for now lets see if you can get it going for passing emissions).

Still need pics of the ECU (assume its OE). Check what you can (temp sensor) throttle position sensor (cant recall the correct name, the black box on the side of the TB). Just to see if at least those are in spec.

First of all, I just want to say thank you to everyone. It's awesome getting all of this advice, even if it's somewhat overwhelming. So much we still have to learn.

Here are a bunch of pictures. Hope is helps with a few of the questions. Just let me know what I'm missing of where to change angle and I'll go take more.

The car is a 280z (they mistakenly put 280zx on the emissions). VIN is HLS30-432877.

Engine block is stamped L28 652773. Not sure how to look that up to know where it came from, but I was told it was purchased to put into the frame by previous owner. Don't know much more about it than that...

ECU appears to be OE (attached pic), though I didn't pull it out fully. AFM appears to be JEGS after market. I'm not sure how to check to see if cams are original, but will research.

Spark plugs were changed when we redid all of the fuel and liquids. Probably 30 miles of driving and a decent amount more idling as we worked on different parts getting it running. They're pretty dirty (see picture). I'll get new ones to use for testing.

Also getting ready to order a fuel injection test kit to use. Be here in a couple of days.

18 hours ago, thetwood said:

He was a high school kid. Why do they do anything? I know my high schooler doesn't always make the best of decisions... But wish it would have been left closer to stock.

I'm 50 and make bad decisions. It never stops.

5 minutes ago, thetwood said:

Also getting ready to order a fuel injection test kit to use. Be here in a couple of days.

Did we ever ask how the car runs now? I don't think so...

What the heck is a injector test kit? New one to me but best of luck with the results.

Looks like mostly stock parts. Those pink injectors probably started as tan. The AFM is probably sideways in order to fit that hose connecting to the throttle body, the stock one probably fell apart as they do.  So Dave's fuel pressure recommendation is back on the docket.  Why is it so low?

I wonder if the PO just used the CSV nipple to block a vacuum port.  Maybe trying to pass the visual inspection.

Overall, it seems close, although confusing.  It runs and the emissions numbers are not terrible.  The kit you're waiting for won't have much useful in it except a pressure gauge.  You could probably go to your local auto parts store and borrow a gauge.  Did any raw fuel come out of the vacuum port on the FPR when you were messing with it?  The low pressure readings are still the big oddness.

You should check your cam timing, valve lash, and ignition timing.  You can get it to pass even without the PCV system working correctly.  You might have to change the oil right before you go back.  There's no major thing you're going to find that will make dramatic changes.  Just a bunch of small things to get it right.

19 hours ago, thetwood said:

So maybe the fuel pressure gauge is bad (was in the car when we got it), but at idle it's sitting around 15 psi without the vacuum hooked up. With the vacuum hooked up, it's at 4 psi. I can look at replacing the gauge to see if that's indeed the problem...

Reading through the thread again. Everyone's covering a lot of ground in a short time.

I'm with Site and Zed on the usefullness of the fuel injection test kit. If you want spend money, subsribe to this site. Money well spent. You will help the site and the members are all willing to help with advice.

You could be right on a bad fuel pressure gauge. A new one will set you back $5 to $10. Replacing it would be a good idea.

I think I would concentrate on one thing at a time. Before buying anything, except fuel gauge, I would try to get the fuel pressure adjusted to spec. The fpr seems to react to vacuum correctly so you should be able to use it. Check the specs for the injectors are correct etc.

What concerns me is the low pressure. If it is really so low it could be to compensate big injectors. The origjnal injectors are 185cc, but you could have larger capacity injectors. Can you get a really close photo of the injector with part number?

One other thing about your fuel system. You replaced the leaking fuel cap. Maybe it was "leaking" for a reason. He removed the carbon canister and that is actually the vent for the tank. In you photo it is clear to see he blocked off the pipe with a rubber cap. You need to restore the carbon canister function.

17 minutes ago, EuroDat said:

Reading through the thread again. Everyone's covering a lot of ground in a short time.

We have bombarder this fellow. I apologize for the group. It's a game we play, who's first with the answer.

My smartphone is like the Coleco football game I played when I was a kid.

 

1 hour ago, siteunseen said:

Did we ever ask how the car runs now? I don't think so...

What the heck is a injector test kit? New one to me but best of luck with the results.

Sorry. Is a pressure kit. Just hoping to get better pressure reading than the inline gauge.

It runs okay. The exhaust on it makes it loud and it's not completely smooth, but does fine out on the road.